fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or...
Transcript of fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or...
![Page 1: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/1.jpg)
![Page 2: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/2.jpg)
SKELETO-DENTAL CHARACTERISTICS FEATURES
AMONG SAUDI FEMALE SCHOOL CHILDREN.
A CEPHALOMETRIC STUDY
THESIS
Submitted in partial fulfillment of the requirements for the
MASTER OF SCIENCE DEGREE IN DENTISTRY
(ORTHODONTICS)
BY
SAHAR FAISAL AL-BARAKATI, BDS
Department of Preventive Dental Sciences
King Saud University, College of Dentistry
1416H [1996]
![Page 3: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/3.jpg)
SKELETO-DENTAL CHARACTERISTICS FEATURES
AMONG SAUDI FEMALE SCHOOL CHILDREN.
A CEPHALOMETRIC STUDY
THESIS by
SAHAR AL-BARAKATI
Thesis defended on July 3, 1996 and approved.
Supervisor
DR. MOHAMED BUKHARY
Examination Committee
DR. HAYDER HASHIM DR. RABAB FETEIH
DR. ERNEST GUILE PROF. J.O. ADENUBI
![Page 4: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/4.jpg)
ABSTRACT
The skeleto-dental characteristic features of the different classes
were studied in 205 cephalometric radiographs of Saudi females school
children, representing the age range of 10 – 12 years. The sample was
selected from a pool of 5112 subjects in Jeddah City.
Two hypothesis were stated, tested and the results of the study
suggest accepting the hypothesis.
18 angular, 17 linear and 2 proportional variables were
investigated. Descriptive statistics and student t-test were used for the
data Descriptive statistics and student t-test were used for the data
analysis. The error of the method was calculated and found to be within
the acceptable range.
The distribution of the skeletal relationship revealed that 68.3%
of the sample showed class I relationship, 16.1% class II and 15.6%
class III.
The skeleto-dental characteristic features of class II and class III
were compared to class I of this Saudi sample. The result indicates
significant differences between the different classes.
Class II skeletal relationship was found to be due to maxillary
protrusion and retrusion of the mandible, whereas, class III relationship
![Page 5: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/5.jpg)
was due to retruded maxilla and relatively normal and/or protruded
mandible.
The results also revealed that the upper incisors were retroclined
and the lower incisors were procline in class II skeletal relationship.
The opposite was observed in class III.
Besides, the results obtained for class I in the Saudi sample were
compared to the established mean for the North American Caucasians
and British. The Saudi female skeleton-dental characteristic feature
was found to be neared to the British sample than the North American
Caucasians. However, the dento-alveolar relationship variables showed
more protrusion of the upper and lower incisors (Bimaxillary
protrusion).
The results obtained can be of great value not only in
distinguishing the various skeleton-dental features in the different
skeletal classes among the Saudi females but also in the clinical
diagnosis and treatment planning.
Furthermore, the results of the study can also serve as base-line
for future investigations in Saudi Arabia.
![Page 6: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/6.jpg)
6
TABLE OF CONTENTS
Abstract 4
Table of Contents 6
List of figures 11
List of tables 12
Dedication 19
Acknowledgements 20
1.0 Introduction 22
2.0 Review of Literature 25
2.1 Malocclusions and skeletal discrepancy 26
2.1.1 Normal occlusion 26
2.1.2 Malocclusion 26
2.1.3 Skeletal discrepancy 29
2.1.4 The role of genetic factors in the
production of malocclusion 32
2.1.5 The role of environment factors in
the production of malocclusion 33
2.2 The growth of the cranio-facial skeleton 36
2.2.1 Growth mechanism 36
2.2.1. a Cortical drift 36
2.2.1. b Displacement 37
2.2.1. c Remodeling 38
2.2.2 Growth of the midface 38
2.2.3 Maxillary growth 38
2.2.4 Mandibular growth 39
2.2.5 Intermaxillary relationship 41
2.2.6 Growth consideration 41
2.3 Racial variation 42
![Page 7: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/7.jpg)
7
2.4 Cephalometric radiography 44
2.4.1 Short historical background 44
2.4.2 The uses of cephalometry 47
2.4.3 Errors of cephalometry 48
2.5 Cephalometric methods of assessing skeletal
relationship 52
2.5.1 ANB angle 52
2.5.2 Wits analysis 54
2.5.3 A-B plane angle 55
2.5.4 Ballard conversion method 56
2.5.5 A-B/functional occlusal plane angle 57
2.5.6 The archival analysis 58
2.6 Cephalometric studies on the Caucasian 61
2.6.1 Cephalometric studies on normal skeletal
relationship 61
2.6.2 Cephalometric studies on Class II skeletal
relationship 65
2.6.3 Cephalometric studies on Class III skeletal
relationship 70
2.7 Cephalometric studies in Saudi Arabia 80
2.8 Incidence of skeletal discrepancy 84
3.0 Statement of the problem and purpose of the study 90
3.1 The aims of the present study 91
4.0 Material and Method 93
4.1 Material 94
4.1.1 Criteria sample selection 94
4.1.2 Tracing technique 95
4.1.2.1 Cephalometric landmarks 95
4.1.2.1.a Definition of the landmarks 95
4.1.3 Digitization 100
![Page 8: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/8.jpg)
8
4.1.3.1 Constructed landmarks 101
4.1.3.2 Cephalometric planes and lines 102
4.1.3.2.a The horizontal planes 102
4.1.3.2.b The vertical planes and lines 102
4.1.3.3 Angular measurements 104
4.1.3.4 Linear measurements 107
4.1.3.5 Proportional measurements 112
4.2 Assessment of method error 115
4.2.1 Assessment of cephalometric error 116
4.2.1.a Systematic error 116
4.2.1.b Random error 117
4.3 Assessing skeletal relationship 119
4.4 Assessing the skeleto-dental characteristic features of the
class II and class III groups 120
4.5 Comparison of Saudi skeleton-dental characteristics
to established cephalometric standards 121
4.6 Statistical analysis of the data 122
4.6.1 Descriptive analysis 122
4.6.2 Statistical assessment of method error 123
4.6.2.1 Dahlberg’s method error 123
4.6.2.2 Coefficient of reliability 123
4.6.3 Statistical comparison between the groups 124
4.6.3.1 Comparison between the Saudi control
group and the Saudi class II
and class III groups 124
4.6.3.2 Comparison of the Saudi control group
to established cephalometric
standards 125
4.6.3.3 The level of significance used
for comparing the samples 126
5.0 Results 127
5.1 The method error and reliability of
cephalometric landmarks 129
![Page 9: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/9.jpg)
9
5.2 The skeletal classification of the 205
Saudi females based on ANB angle and
their distribution 134
5.3 The skeleto-dental characteristics of the
class II and class III skeletal relationship
compared to the class I skeletal relationship of
Saudi females. 136
5.3.1 Skeletal relationship 136
5.3.2 Cranial base 136
5.3.3 Maxilla 137
5.3.4 Mandible 137
5.3.5 Dento-alveolar relationship 137
5.4 Comparison of the skeletodental
characteristics of Saudi female class
I skeletal relation (control group) to
established mean value of North
American white, Riolo, et al (1974)
and British Caucasian, Bhatia and
Leighton (1993) 160
5.4.1 Skeletal relationship 160
5.4.2 Cranial base 160
5.4.3 Maxilla 161
5.4.4 Mandible 161
5.4.5 Dento-alveolar relationship 161
6.0 Discussion 183
6.1 Material and method used 184
6.2 The method error and reliability 186
6.3 The skeletal classification of Saudi sample 188
6.4 The skeleton- dental characteristics of class II
and class III Saudi sample 189
6.4.1 Skeletal relationship 190
6.4.1.a The antero posterior skeletal
relationship 190
6.4.1.b. Vertical skeletal relationship 190
6.4.2 Cranial base 192
6.4.3 Maxilla 193
6.4.4 Mandible 194
6.4.5 Dento alveolar relation 196
![Page 10: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/10.jpg)
10
6.4.5.1 Maxillary incisor position 196
6.4.5.2 Mandibular incisor position 198
6.4.5.3 Inter incisal angle 199
6.5 Comparison of the skeleton-dental characteristics
of Saudi female to established cephalometric
standards 199
6.5.1 Skeletal relationship 200
6.5.1.a Anteroposterior skeletal relationship 200
6.5.1.b Vertical relationship 201
6.5.2 Cranial base 202
6.5.3 Maxilla 202
6.5.4 Mandible 203
6.5.5 Dento alveolar relationship 203
7.0 Conclusion 205
7.1 Some suggestion for future studies 208
8.0 References 209
![Page 11: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/11.jpg)
11
List of Figures
Figure No.
Figure 1: Illustration of angle classification 28
Figure 2: Illustration of incisor relationship classification 29
Figure 3: Illustration of class I, II, III skeletal relationship 30
Figure 4: Illustration of the angle SNA, SNB and the subtracted ANB 53
Figure 5: Illustration of Wits method 54
Figure 6: Illustration of the A-B plane angle 55
Figure 7: Illustration of Ballard’s conversion method 56
Figure 8: Illustration of the A-B/functional occlusal plane angle 57
Figure 9: Illustration of the archial analysis 59
Figure 10: Illustration of cephalometric landmarks 90
Figure 11: The computer and the digitizer used 100
Figure 12: Illustration of constructed cephalometric landmarks 101
Figure 13: Illustration of horizontal cephalometric planes 103
Figure 14: Illustration of vertical cephalometric planes 105
Figure 15: Illustration of angular measurement of anteroposterior
skeletal relationship 108
Figure 16: Illustration of angular measurements of vertical skeletal
relationship 109
Figure 17: Illustration of angular measurements of dental relationship 110
Figure 18: Illustration of linear measurements of skeletal relationship 113
Figure 19: Illustration of linear measurements of dental relationship 114
Figure 20: Pie chart of the frequency and percentage of the skeletal
discrepancy of 205 Saudi female classified by the ANB angle 135
![Page 12: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/12.jpg)
12
List of Tables
Table No.
Table 2.8.1 Surveys of the prevalence of malocclusion based on
Angle’s and incisor classification 85
Table2.8.2 Surveys of the prevalence of skeletal discrepancy
classification 87
Table 5.1.1 The method error and reliability of cephalometric
landmarks of the angular measurements. 131
Table 5.1.2 The method error and reliability of cephalometric
landmarks of the linear measurements 132
Table 5.1.3 The method error and reliability of cephalometric
landmarks of the proportional measurements 133
Table 5.2.1 The skeletal classification of the 205 Saudi females
based on ANB angle and their distribution 135
Table 5.3.1.a.1 The mean and spread of measuring the ANB angle
in degrees recorded for the class I, II and III skeletal
relationship of Saudi females 139
Table 5.3.1.a.2 The mean and spread of measuring the A-B plane
angle in degrees recorded for the class I, II and III
skeletal relationship of Saudi females 140
Table 5.3.1.a.3 The mean and spread of measuring the angle of
convexity in degrees recorded for class I, II, III
skeletal relationship of Saudi females 140
Table 5.3.1.b.1 The mean and spread of measuring the SN/MP1 angle
in degrees recorded for class I, II, III skeletal
relationship of Saudi females 141
Table 5.3.1.b.2 The mean and spread of measuring the SN/occ angle
in degrees recorded for class I, II, III skeletal
relationship of Saudi females 141
![Page 13: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/13.jpg)
13
Table 5.3.1.b.3 The mean and spread of measuring the FH/MP2
angle in degrees recorded for class I, II, III
skeletal relationship of Saudi females 142
Table 5.3.1.b.4 The mean and spread of measuring the FH/occ
angle in degrees recorded for class I, II, III
skeletal relationship of Saudi females 142
Table 5.3.1.b.5 The mean and spread of measuring Y-axis angle
in degrees recorded for class I, II, III
skeletal relationship of Saudi females 143
Table 5.3.1.b.6 The mean and spread of measuring facial axis
angle in degrees recorded for class I, II, III
skeletal relationship of Saudi females 143
Table 5.3.1.b.7 The mean and spread of measuring gonial angle
in degrees recorded for class I, II, III
skeletal relationship of Saudi females 144
Table 5.3.1.b.8 The mean and spread of measuring lower facial
height in mm recorded for class I, II, and III
skeletal relationship of Saudi females 145
Table 5.3.1.b.9 The mean and spread of measuring anterior
facial height in mm recorded for class I, II, and III
skeletal relationship of Saudi females 145
Table 5.3.1.b.10 The mean and spread of measuring posterior
facial height in mm recorded for class I, II, and III
skeletal relationship of Saudi females 146
Table 5.3.1.b.11 The mean and spread of measuring ramus
facial height in mm recorded for class I, II, and III
skeletal relationship of Saudi females 146
Table 5.3.1.b.12 The mean and spread of measuring
ANS-Me/N-Me in percentage recorded for
class I, II, and III skeletal relationship
of Saudi females 147
Table 5.3.1.b.13 The mean and spread of measuring S-Go/N-Me in
percentage recorded for class I, II, and III
skeletal relationship of Saudi females 147
![Page 14: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/14.jpg)
14
Table 5.3.2.1 The mean and spread of measuring S-N in mm
recorded for class I, II, and III skeletal
relationship of Saudi females 148
Table 5.3.2.2 The mean and spread of measuring S-ar in mm
recorded for class I, II, and III skeletal
relationship of Saudi females 148
Table 5.3.2.3 The mean and spread of measuring saddle angle
in degrees recorded for class I, II, and III
skeletal relationship of Saudi females 149
Table 5.3.3.1 The mean and spread of measuring SNA angle in
degrees recorded for class I, II, and III skeletal
relationship of Saudi females 150
Table 5.3.3.2 The mean and spread of measuring A/N ┴ angle in
FH in mm recorded for class I, II, and III skeletal
relationship of Saudi females 150
Table 5.3.4.1 The mean and spread of measuring SNB angle in
degrees recorded for class I, II, and III skeletal
relationship of Saudi females 152
Table 5.3.4.2 The mean and spread of measuring facial angle
in degrees recorded for class I, II and III skeletal
relationship of Saudi females 152
Table 5.3.4.3 The mean and spread of measuring pog/N ┴ FH
in mm recorded for class I, II and III skeletal
relationship of Saudi females 153
Table 5.3.4.4 The mean and spread of measuring pog/NB
in mm recorded for class I, II and III skeletal
relationship of Saudi females 153
Table 5.3.4.5 The mean and spread of measuring mandibular
body in mm recorded for class I, II and III
skeletal relationship of Saudi females 154
Table 5.3.4.6 The mean and spread of measuring mandibular
length in mm recorded for class I, II and III
skeletal relationship of Saudi females 154
![Page 15: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/15.jpg)
15
Table 5.3.5.a.1 The mean and spread of measuring UIE/NA
in mm recorded for class I, II and III skeletal
relationship of Saudi females 155
Table 5.3.5.a.2 The mean and spread of measuring UIE/A ┴ FH
in mm recorded for class I, II and III
skeletal relationship of Saudi females 155
Table 5.3.5.a.3 The mean and spread of measuring UIE/Apog
in mm recorded for class I, II and III skeletal
relationship of Saudi females 156
Table 5.3.5.a.4 The mean and spread of measuring UIA-UIE/NA
in degrees recorded for class I, II and III skeletal
relationship of Saudi females 156
Table 5.3.5.b.1 The mean and spread of measuring LIE/NB in
mm recorded for class I, II and III skeletal
relationship of Saudi females 157
Table 5.3.5.b.2 The mean and spread of measuring LIE/Apog in
mm recorded for class I, II and III skeletal
relationship of Saudi females 157
Table 5.3.5.b.3 The mean and spread of measuring LIE-LIA/NB
in degrees recorded for class I, II and III
skeletal relationship of Saudi females 158
Table 5.3.5.b.4 The mean and spread of measuring LIA-LIE/MP2
in degrees recorded for class I, II and III
skeletal relationship of Saudi females 158
Table 5.3.5.c.1 The mean and spread of measuring interincisal
angle in degrees recorded for class I, II and III
skeletal relationship of Saudi females 159
Table 5.4.1.a.1 The mean and spread of measuring ANB in
degrees recorded for class I of Saudi female,
North American Caucasian British Caucasian. 162
Table 5.4.1.a.2 The mean and spread of measuring AB plane
Angle in degrees revorded for Class I of Saudi female 163
Table 5.4.1.a.3 The mean and spread of measuring angle
of convexity in degrees recorded for Class I of
Saudi female 163
![Page 16: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/16.jpg)
16
Table 5.4.1.b.1 The mean and spread of measuring SN/MP in
degrees recorded for class I of Saudi female 164
Table 5.4.1.b.2 The mean and spread of measuring SN/occ in
degrees recorded for class I of Saudi female 16
Table 5.4.1.b.3 The mean and spread of measuring FH/MP2
In degrees recorded for class I of Saudi female 165
Table 5.4.1.b.4 The mean and spread of measuring FH/occ in
degrees recorded for class I of Saudi female 165
Table 5.4.1.b.5 The mean and spread of measuring Y-axis angle
in degrees recorded for class I of Saudi female 166
Table 5.4.1.b.6 The mean and spread of measuring facial axis
angle in degrees recorded for class I of Saudi
female 166
Table 5.4.1.b.7 The mean and spread of measuring gonial angle
in degrees recorded for class I of Saudi female 167
Table 5.4.1.b.8 The mean and spread of measuring ANS-Me
in mm recorded for class I of Saudi female 168
Table 5.4.1.b.9 The mean and spread of measuring N-Me
in mm recorded for class I of Saudi female 168
Table 5.4.1.b.10 The mean and spread of measuring S-Go
in mm recorded for class I of Saudi female 169
Table 5.4.1.b.11 The mean and spread of measuring ramus height
in mm recorded for class I of Saudi female 169
Table 5.4.1.b.12 The mean and spread of measuring ANS-Me/N-Me
in percentage recorded for class I of Saudi female 170
Table 5.4.1.b.13 The mean and spread of measuring S-G0/N-Me
in percentage recorded for class I of Saudi female 170
Table 5.4.2.1 The mean and spread of measuring S-N in mm angle
recorded for class I of Saudi female 171
Table 5.4.2.2 The mean and spread of measuring S-Ar in mm
recorded for class I of Saudi female 171
![Page 17: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/17.jpg)
17
Table 5.4.2.3 The mean and spread of measuring saddle angle
in degrees recorded for class I of Saudi female 172
Table 5.4.3.1 The mean and spread of measuring SNA in
degrees recorded for class I of Saudi female 173
Table 5.4.3.2 The mean and spread of measuring A/N ┴ FH
mm recorded for class I of Saudi female 173
Table 5.4.3.3 The mean and spread of measuring maxillary
length in mm recorded for class I of Saudi
female 174
Table 5.4.4.1 The mean and spread of measuring SNB in
degrees recorded for class I of Saudi female 175
Table 5.4.4.2 The mean and spread of measuring facial angle
in degrees recorded for class I of Saudi female 175
Table 5.4.4.3 The mean and spread of measuring mandibular
body length in mm recorded for class I
of Saudi female 176
Table 5.4.4.4 The mean and spread of measuring mandibular
length in mm recorded for class I of Saudi female 176
Table 5.4.4.5 The mean and spread of measuring Pog/N ┴
in mm recorded for class I of Saudi female 177
Table 5.4.4.6 The mean and spread of measuring Pog/NB
in mm recorded for class I of Saudi female 177
Table 5.4.5.a.1 The mean and spread of measuring UIE/NA
in mm recorded for class I of Saudi female 178
Table 5.4.5.a.2 The mean and spread of measuring UIE/A ┴ FH
in mm recorded for class I of Saudi female 178
Table 5.4.5.a.3 The mean and spread of measuring UIE/A Pog
in mm recorded for class I of Saudi female 179
Table 5.4.5.a.4 The mean and spread of measuring UIA-UIE/NA
in mm recorded for class I of Saudi female 179
Table 5.4.5.b.1 The mean and spread of measuring LIE/NB
in mm recorded for class I of Saudi female 180
![Page 18: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/18.jpg)
18
Table 5.4.5.b.2 The mean and spread of measuring LIE/A pog
in mm recorded for class I of Saudi female 180
Table 5.4.5.b.3 The mean and spread of measuring LIE-LIA/NB
in degrees recorded for class I of Saudi female 181
Table 5.4.5.b.4 The mean and spread of measuring LIA-LIE/MP2
in degrees recorded for class I of Saudi female 181
Table 5.4.5.c.1 The mean and spread of measuring interincisal
angle in degrees recorded for class I of Saudi female 182
![Page 19: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/19.jpg)
19
DEDICATION
I am indebted with gratitude to my husband SALEH, and my
sweet kids Hashim, Talal and …… for giving me understanding, active
encouragement, fullest patience and unfailing support during the period
of the study. May Allah bless you all for everything you did for me.
I must also extend a note of gratitude to my mother, who had
encouraged me to pursue my studies and gave me her full support,
never expecting anything in return. I would like also to thank my father
and brothers especially my brother Mohammed, for their fullest
support.
Thank you very much!
![Page 20: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/20.jpg)
20
ACKNOWLEDGEMENTS
As a Saudi Arabian citizen and a female who got the
opportunity to proceed in education to postgraduate level, there is
inevitably a number of people to acknowledge both their time and
assistance.
Firstly, I am grateful to the Kingdom of Saudi Arabia, the
Ministry of Higher Education, and King Saud University in Riyadh for
making postgraduate studies available in specialized fields. I am also
grateful to the administration at the College of Dentistry, Preventive
Dental Science Department.
Secondly, I would like to express my sincere thanks to my
supervisor, the late Professor Hafizuddin Shaikh, who did not live long
enough to witness the completion of this study. He has been an
excellent teacher and sincere guide during the early process of this
work. May Allah bless him in the hereafter.
I wish to express my sincere thanks and gratitude to Dr.
Mohammed Bukhary, Head of the Orthodontics Division, for his
immerse help, invaluable advice, and guidance in the supervision of
this thesis. I am most grateful for everything.
I would like to thank sincerely Dr. Ibrahim Masoud, for his
generosity in providing me with such valuable cephalograms of the
Saudis sample which are used in this study. I really appreciate his
kindness.
![Page 21: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/21.jpg)
21
I would also like to thank Mrs. Vilma S. Dizon, Malou Eleazar,
Babes Lima and Cirila Libutaque for their patience in typing the
manuscript as well as Mrs. Susan Wong for producing the slides.
![Page 22: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/22.jpg)
22
1.0 INTRODUCTION
![Page 23: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/23.jpg)
23
1.0 INTRODUCTION
Skeletal Discrepancy has a major role in producing
malocclusion. Antero-posterior skeletal discrepancy is associated with
class II and class III malocclusion, vertical discrepancy is associated
with anterior open bite or deep bite, and transverse discrepancy with
cross bite, scissors bite and center line shifting. Its assessment is,
therefore, essential for proper diagnosis, and for planning orthodontic,
dentofacial orthopedic or orthognathic surgical treatment.
The Skeletal relationship is the underlying skeleton of the jaw,
excluding the dentoalveolar process. It may also be referred to as the
skeletal pattern or dental base relationship. It includes the jaw size, the
relationship of the jaws to each other and their relation to the cranial
base.
The skeletal relationship has been the subject of interest and
concern to many investigators (Bjork, 1947; Sassouni, 1955; Pascoe et
al., 1960; Mills, 1966; Jacobson et al., 1980; Stoelinga and leenen,
1981; Ellis and McNamara, 1984; Rosenblum, 1995).
However, most of the previous studies of the skeletal
relationship have focused on the Caucasian, and have been carried out
in Western Sociaties. In Saudi Arabia, though a number of studies had
been carried out to determine the extent of malocclusion (Nashashibi),
et al. , 1983; Al-Shammery and Guile, 1986; and Al-Emran, 1988).
The underlying skeletal morphology of Saudi population has so far, not
been well investigated (Jones, 1987 and Toms, 1989).
![Page 24: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/24.jpg)
24
Furthermore, since one of the main aims of orthodontic
treatment is to improve the facial esthetics, a patient having skeletal
discrepancy may demand to correct the skeletal relationships as well as
the dental occlusion. Thus, in addition to the established information
regarding dental malocclusion, an accurate knowledge about the
skeletal disharmony is important for the planning and understanding of
orthodontic treatment and management.
![Page 25: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/25.jpg)
25
2.0 REVIEW OF LITERATURE
![Page 26: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/26.jpg)
26
2.1 Malocclusion and skeletal discrepancy
Assessment of malocclusion is an important aspect in
orthodontics, as understanding the nature of the deformity provides
keys to the planning of treatment.
2.1.1 Normal malocclusion
Normal occlusion was defined by Houston and Tulley (1986) as
the term encompassing minor deviations from the ideal that do not
continue aesthetic or functional problems. The limits of normal
occlusion cannot be specified precisely, and so there can be
disagreement between experienced clinicians about categorization of
borderline cases (for example, a minor irregularity).
2.1.2 Malocclusion
Malocclusion was defined by Houston (1983) as the term
encompassing all deviations of the teeth from the normal relation,
including a number of distinct conditions which may or may not be
independent. Such deviations involve the mal-position of the individual
teeth (rotation, tipping, over or under eruption), discrepancies between
teeth size and jaw size (crowding and spacing).
![Page 27: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/27.jpg)
27
Several methods of classifying malocclusion have been described,
but the one which has gained most widespread use is that of Angle
(1898). Angle defined three classes of malocclusion based on the
antero-posterior relationship of the upper and lower buccal segments
(Fig. 1).
Class I: in which there was a normal antero-posterior
relationship (the anterobuccal cusp of the upper first
permanent molar occludes in the mesial buccal groove
of the lower first permanent molar).
Class II: in which the mandibular buccal segments were distal
to those of the maxilla.
This malocclusion was further divided into two
categories: class II, division I in which there was an
excessive overjet; and class II, division 2 in which the
upper central incisors were retroclined, the overbite is
greater than normal and the overjet was normal.
Class III: in which the mandibular buccal segments were mesial
to those of the maxilla..
![Page 28: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/28.jpg)
28
Figure 1: Illustration of Angle classification
The second classification which was widely adopted was the
incisor classification (Houston, 1983) since the patients were generally
more concerned with anterior teeth correction rather than with the
buccal segments. The incisor classification was based upon the
relationship between the lower incisor edges and the cingulum plateau
of the upper central incisor (Fig. 2).
Class I: The lower incisor edges occlude with or lie
immediately below the cingulum plateau (middle part
of the palatal surface) of the upper central incisors.
![Page 29: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/29.jpg)
29
Class II: The lower incisor edges lie posterior to the cingulum
plateau of the upper central incisors. There were two
divisions of class II:
Division 1: The upper central incisors were of
average inclination or were proclined. The overjet
was thus, increased.
Division 2: The upper central incisors were
retroclined.
Class Ill: The lower incisor edges lie anterior to the cingulum
plateau of the upper central incisors.
Class I Class II Division 1 Class II Division 2 Class III Figure 2: Illustration of incisor relationship classification
2.1.3 Skeletal discrepancy
In identifying malocclusion, it is important to look at the skeletal
relation, since it was accepted that skeletal variation was the
primary
![Page 30: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/30.jpg)
30
cause of malocclusion. Foster (1990) defined the skeletal relationship
as the antero-posterior positional relationship of the basal parts of the
upper and lower jaws to each other, with the teeth in occlusion. When
the jaws were in their normal antero-posterior relationship in occlusion
there was a class I skeletal relationship. Any deviation from this
situation will lead to class II and class III skeletal relationships (Fig. 3).
Figure 3: Illustration of class I, II, III skeletal relationships
Foster (1990) defined skeletal class II as occuring when the lower
jaw in occlusion was positioned further backward than in skeletal class
I. It was characterized by the lower jaw in a distal or posterior relation
to the upper jaw. This was reflected by the class II first permanent
molar relationship. It has a retrognathic profile, and as a result, the
mandible was placed posteriorly relative to the maxilla with either a
small
![Page 31: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/31.jpg)
31
mandible, a large maxilla, or a combination of both. It has increased
overjet in class II, division 1, and deep overbite in addition to a labio-
version of the maxillary lateral incisors in class II division 2. Sassouni
(1969) described this skeletal relationship by means of 2 types, the
skeletal openbite and skeletal deepbite.
Joffe (1965) defined the class III skeletal relationship as a disorder
of craniofacial growth in which the facial profile was marred by an
undue prominence of the mandible. Houston and Tulley (1986) defined
it as protrusion of the lower dental base relative to the upper. It was
typified by a concave profile with an appearance of mandibular
prognathism, a reduced or negative incisor overjet, and class III mal
occlusion. There were two basic morphologic types: the divergent and
the convergent. The characteristic features of the divergent type
include palatal, occlusal and mandibular planes which diverge, an
obtuse gonial angle, and an anterior open bite in extreme cases. The
convergent class III had palatal, occlusal and mandibular planes that
tended toward parallelism, an acute gonial angle and a deep anterior
overbite (Jacobson et al., 1974).
McCallin (1955) described class III skeletal relationship by means
of two extremes, one in which the gonia I angle was very high and the
other in which it was very low.
![Page 32: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/32.jpg)
32
2.1.4 The role of genetic factors in the production of mal-occlusion.
A strong influence of inheritance on facial features was obvious at
a glance. It was easy to recognize familial tendencies in the tilt of the
nose, the shape of the jaw and the look of the smile. It was apparent
that certain types of malocclusion run in families (Tanner, 1989).
Malocclusion could be most probably produced by inherited
characteristics in two ways. The first would be an inherited
disproportion between the size of the teeth and the size of the jaws,
which would produce crowding or spacing. The second possibility
would be an inherited disproportion between size or position of the
upper and lower jaws, which would cause improper occlusal
relationships and the development of inter-arch variations in antero-
posterior, vertical and transverse dimensions which would produce
class 11 and/or class III skeletal discrepancy (Proffit, 1992).
Mills (1982) stated that "it is in fact generally accepted that the
genes play a large part in producing the face and the dentition of the
individuals”. Among the most famous examples of inheritance was the
Habsburg jaw of the German Royal family (Bertram, 1959), the
prognathic mandible, the protruding lower lip, and the well-known
Habsburg nose, with its prominent dorsal hump. Bertram (1959) has
illustrated the role of heredity by tracing the course of class III skeletal
![Page 33: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/33.jpg)
33
relationship over several centuries in the Habsburgs. Of forty members
of the family for whom sufficient records remain thirty three showed
prognathism. Other authorities (Stiles and Luke, 1953; Litton et al.,
1970; Rakosi and SchiIIi, 1981) also agreed that there appears to be a
strong genetic influence in determining the occurrence of skeletal
discrepancy. Stiles and Luke (1953) pointed out that skeletal
discrepancy was inherited via a dominant gene with an unknown
degree of reduced penetrance. Litton et al. (1970) found in studying the
influence of inherited tendencies that, one third of a group of children
who presented with severe class III malocclusion had a parent with the
same problem, and one sixth had an affected sibling. Rakosi and
SchiIIi (1981) mentioned that the growth and size of the mandibular
base was predetermined by heredity. Harris and Johnson (1991)
examined longitudinal cephalometric radiographs and dental casts of
siblings who participated in the Bolton-Brush growth study. They
concluded that the heritability of craniofacial (skeletal) characteristics
was high, but that of dental characteristics was low.
2.1.5 The role of environmental factors in the production
of malocclusion.
There is no doubt, however, that environmental factors play a role
in the establishment of facial proportions and dental relationships.
![Page 34: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/34.jpg)
34
Environmental influences during the growth and development of the
face, jaws, and teeth consist largely of pressures and forces of
physiologic activity (Watson et al., 1968; Warren, 1984; Turvey et al.,
1984; Proffit, 1992). Function must adapt to the environment, as when,
chew and swallow were determined by diet because pressure against
the jaws and teeth affect jaw growth and tooth eruption. When function
could affect the growth of the jaws, altered function could be a major
cause of malocclusion (Proffit, 1972; Steedle and Proffit, 1985). But
when the function makes little or no difference to the individual's
pattern of development, altering the jaw function would have little if
any impact etiologically or therapeutically (Proffit, 1992).
References have also been made to environmental disturbances
such as trauma, sucking habits, and childhood illness as contributing to
the wide dento-facial variations that arise, even within families (Shaw,
1992).
Thompson and Jurgens (1956) described several acquired factors
which may produce the class III skeletal relationship. Included in their
list was trauma (such as fractures of the mandible) and even certain
infections such as osteomyelitis of the mandible which on occasion
may produce a hyperplastic reaction resulting in class III skeletal
relationship. Rakosi and Schil I (1981) pointed out that a flat anteriorly
located tongue was also responsible for the anterior position of the
mandible, and that the children with skeletal discrepancy can have
contributing habits; there was
![Page 35: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/35.jpg)
35
a positive habit history in 64% of cases (in children without
malocclusion, it was 54%).
Mouth breathing, especially in patients with enlarged tonsils, can
likewise promote the development of skeletal discrepancy (Niinimaa,
1981; Harvold, 1981). The tongue of mouth breathers was always fiat,
which causes a wide mandibular dental arch and narrow maxillary arch
with a high palate.
Occlusal force with unfavorable incisal guidance can also
promote the skeletal discrepancy (Rakosi and Schilli, 1981).
![Page 36: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/36.jpg)
36
2.2 Growth of the cranio-facial skeleton.
Enlow (1990) defined the facial growth and development as a
morphogenic process working toward a composite state of structural
and functional balance among all of the hard and soft tissue parts.
Facial growth was a complex phenomenon and its understanding
requires the study in depth of the changes that occur from infancy to
adulthood. However, the clinician should be aware of the basic
principles underlying the growth mechanisms, for they are significant
when assessing the etiology of malocclusion and the possible method
of treatment (Nielsen, 1991).
2.2.1 Growth mechanisms
The theory that bones grow by simple symmetrical enlargement
was wrong (Enlow, 1975). Such a simple growth mechanism could not
possibly create such a complex and differentiated morphology as that
of the mandible or maxilla. Such morphology demands differential
growth mechanisms, and different types of development for the
individual bones.
The following three mechanisms are important for the growth:
2.2.1.a Cortical drift (increase in size).
Direct bone growth by means of deposition and resorption
processes on the bone surfaces, cause the cortical plate to drift (Enlow,
![Page 37: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/37.jpg)
37
1975). The bony cortical plate drifts by depositing and resorbing bone
substance on the outer and inner surfaces, respectively, in the direction
of growth. When, due to cortical drift, all other parts of structure
undergo shifts in relative position, this movement was termed
relocation. During the developmental period, deposition takes place at
a slightly faster rate than resorption, so that the individual bones slowly
enlarge.
2.2.1.b Displacement.
Apart from direct bone growth due to deposition and resorption, the
second process of growth mechanism which takes place was termed
displacement, i.e. the translatory movement of the whole bone caused
by the surrounding physical forces of adjacent structures. The entire
bone was carried away from its articular interfaces (sutures, condyles)
with adjacent bones. Displacement in conjunction with bone's own
growth was termed "primary displacement" (Enlow, 1990). But
displacement due to the enlargement of bones and soft tissue which
were not immediately adjacent was termed "secondary displacement"
(Enlow, 1990). Displacement was initiated by the sum of the expansive
forces of the soft tissues in the growing face creating a space around
the contact surfaces into which the bone can enlarge. The degree of
displacement equals the amount of new bone deposition, although the
direction of displacement was always opposite to that of the bone
deposition.
![Page 38: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/38.jpg)
38
2.1.c Remodeling (change in shape).
As a result of relocation and displacement, further adaptive bone
remodeling was necessary in order to adjust the shape and size of the
area to the new relationship. Selective resorption and apposition
processes functionally remodel the area to conform to the new
physiological loading. The information which initiates the remodeling
process was contained within the various soft tissues surrounding the
bone.
2.2.2 Growth of the midface.
The horizontal growth of the mid face was determined by the
expansion of the anterior cranial fossa, which enlarges anteriorly to an
extent that matches the sagittal development of the maxilla. The
resorption and deposition processes on the endocranial and ectocranial
. surfaces lead to displacement and remodeling of the underlying
structures (nasal bone, ethmoid bone). Thus, the horizontal
development of the midface was balanced inferiorly with the antero-
posterior elongation of the maxilla and superiorly with the horizontal
extension of the anterior cranial fossa.
2.2.3 Maxillary growth.
Maxillary remodeling involves bone deposition on the posterior wall
of the maxillary tuberosity, resulting in a posterior lengthening of the
![Page 39: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/39.jpg)
39
bony maxillary arch (Bjork and Skieller, 1974). Deposition on the
outer surfaces of the tuberosities and resorption on the inner surfaces
causes the cortical plate to drift in a backward direction. This posterior
elongation of the upper jaw was coupled with primary displacement of
the maxilla which was directed anteriorly and exactly equals the
amount of posterior lengthening.
Due to growth of the middle cranial fossa, the maxilla, the
anterior cranial base, the forehead, and the zygoma were shifted in a
forward direction. This process leads to secondary displacement of the
maxilla, i.e. it was displaced passively due to expansion of the middle
cranial fossa without the growth processes of the maxilla itself being
directly involved.
During vertical displacement of the midface, the maxillary arch
was displaced in a downward direction due to resorption on its nasal
surface and simultaneous deposition on its palatal surface. The
downward movement of the maxilla was usually not parallel, but
differs anteroposteriorly. The result was a rotational movement of the
maxilla.
2.3.4 Mandibular growth.
Contrary to previous theories, the condyles do not govern the
growth of the entire mandible, but act locally. Some theorists such as
![Page 40: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/40.jpg)
40
Bjork (1968) and Petrovic (1974) claimed that the pressure exerted on
the
glenoid cavity by the growing condyle caused displacement of the
mandible out of articular contact. However, experiments have shown
that, even after condyles have been removed, the mandible can assume
a normal position which indicate that the condyle was irrelevant to the
growth of other mandibular structures.
When assessing mandibular growth, it should be remembered that
the mandibular corpus during its remodeling was elongated posteriorly
by the same amount as the maxilla (Enlow, 1990). Elongation of the
mandible toward the ramus was possible because the anterior surface
of the ramus was remodeled by resorption into the elongated
mandibular corpus. Simultaneously, the entire mandible was displaced
anteriorly by an amount that equals the maxillary displacement
(primary displacement). The posterior sections of the ramus and
condyles grow diagonally upward and backward, and increase in height
by the same amount of the naso- maxillary complex and middle cranial
base. Growth of the middle cranial base also leads to secondary
mandibular displacement. As the expansion of the middle cranial fossa
is directed forward, a horizontal growth of the ramus will take place.
Simultaneous to the drift of the lower teeth, remodeling takes
place around the chin. Resorption on the outer edge of the anterior
alveolar region and bone deposition on the anterior and inferior
external contours of the symphysis caused the chin to become more
prominent.
![Page 41: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/41.jpg)
41
2.2.5 Intermaxillary relationship.
Simultaneous to maxillary remodeling, active apposition and
resorption processes in the bony alveolar sockets, leads to vertical drift
of the upper teeth. Further, lowering of the upper dentition results from
displacement of the maxilla. Once the upper teeth have moved into
place, an upward drift of the lower teeth and their alveolar processes
commences, thus establishing the final occlusion (Houston and Tulley,
1986).
2.2.6 Growth considerations.
A few basic principles of maxillary and mandibular growth should
be stated here. On average, the peak of the growth spurt occurs at 12
years in girls and at 14 years in boys (Burstone, 1958; Graber, 1972).
The maxilla and the mandible grow in both a downward and forward
direction relative to the cranial base. At the peak of the juvenile growth
spurt (7 to 9 years of age), the maxilla grows 1mm/yr and the mandible
3mm/yr, whereas during the prepubertal period (10 to 12 years of age)
there would be a reduced rate of growth (maxilla 0.25 mm/yr,
mandible, 1.5 mm/yr), only to reach maximum growth levels during
puberty (12 to 14 years of age, maxilla, 1.5mm/yr; mandible,
4.5mm/yr), (Bjork & Skieller, 1972; Behrents, 1986). Overall
mandibular growth was approximately twice that of overall maxillary
growth (Love et al., 1990).
![Page 42: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/42.jpg)
42
2.3 Racial variation.
Population differ in their character, size, growth and shape. These
differences are due to a complicated interaction of genetic and
environmental factors (Tanner, 1989). Distinctions between races by
geographical location, historical origins, culture or language
(Montague, 1942) were usually subsumed into three major racial
groups: Asiatic (or Mongoloid), Black (or Negroid), and White (or
Caucasian) (Montague, 1942; Coon et al., 1950). The classification of
three groups gave each group its own characteristics, which in general
serve to distinguish them from each other.
However, research studies and anthropological findings indicate
that not only did each racial group had its own standards (Miura, 1968;
Drummond, 1968; Guo, 1971; and Baccon et al., 1983), but within the
same race, each subgroup had its own standards, (Burstone, 1958;
Holdaway, 1983; and Nashashibi et al., 1990).
From the above it will be seen that it is illogical to apply the
standards of one racial group to another, or, within the same race, to
apply the standards of one subgroup to another (Cotton et al., 1951;
Kowaliski et al., 1974; Richardson, 1980; Houston and Tulley, 19860).
The literature showed that a lot of studies had been done to
determine the mean values or norms of different subgroups (Bjork,
1947; Steiner, 1953; Hajighadimi et al., 1981; and Haralabakis et al.,
1983).
![Page 43: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/43.jpg)
43
Nevertheless, very little scientific information was available on the
physical characteristics of Arabs. Although Arabs are Caucasian
(Coon, et al., 1950), there is hardly any published scientific research
related to the population of Arabian Peninsula (the Saudi Arabians)
Masoud (1981). However, since they are Caucasians, we can use
established data of Caucasians as a reference for comparison with the
expected variations within the subgroups.
![Page 44: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/44.jpg)
44
2.4 Cephalometric radiography.
Moyers (1988) defined cephalometric radiography or
cephalometrics as a standardized technique employing oriented
radiographs, for the purpose of making head measurements.
2.4.1 Short Historical Background
The principles of cephalometries are patterned closely after the
science of craniometry, which has long been used in anthropology in
the quantitative study of dry skulls, since the head was a fertile area
for researchers in the fields of art, anatomy, and anthropology.
Camper (1722-1792) was one of the first workers to measure the
relationship of the face to the head. He was probably the first to
employ facial angle in measuring the face and its relation to the head
for anthropological studies. The facial angle was formed by the
intersection of the facial line and the horizontal plane. The first line
passes from the most prominent point on the forehead to the point of
contact of the lips, the second line from lower part of the nasal
aperture backward through the center of external auditory meatus. By
using this index, Camper was able to categorize the form of the
crania.
In the nineteenth century, craniologists started to develop
craniostat for orienting dried skulls in order to compare crania, and
began to introduce new baselines. Broca (1873), the inventor of
cephalic index, introduced a new baseline called "plan alveolo
![Page 45: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/45.jpg)
45
condylion" which passes through the alveolar point and tangent to the
inferior surfaces of the two occipital condyles. Von lhering (1872)
introduced a plane which was considered the most important to
evaluate the facial profile and it was accepted by the Anthropological
Congress in Frankfort in 1882 and named the "Frankfort plane". This
line was drawn from the center of each auditory meatus to the lowest
point on the inferior margin of each orbit and which was modified
later on, so that the plane passed through the upper borders of the
bony meati above their centers. With the advent of cephalometric
technique the Frankfort plane remains one of the most important
orientation landmarks.
The discovery of x-rays by Roentgen (1895) allowed
anthropometric examination to utilize profile radiographs of the skull
to obtain a better understanding of the orientation of bones and soft
tissues, thus expanding the horizon of craniometry and cephalometry.
Pacini and Roentgen (1922) won a research award offered by the
American Roentgen Ray Society for his thesis entitled "Roentgen Ray
Anthropometry of the skull". Pacini believed that his procedure would
be useful in the study of human development, classification and
deviations. He recorded a technique for producing and measuring the
anatomical structures of both dried skull and living human head by
roentgenographic projection on lateral head plates. He also identified
certain anthropologic landmarks on the roentgenograms e.g. gonion,
pogonion, nasion, anterior nasal spine.
The simultaneous introduction of the cephalostat in 1931 by
![Page 46: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/46.jpg)
46
Broadbent in USA and by Hofrath in Germany, allowed the head to be
held in a fixed position relative to the x-ray source and to the film. This
proved to be a most important contribution to radiographic assessment
of the facial and skeletal form. The Broadbent cephalostat consisted of
a head positioning device in which the head was secured by ear posts
inserted into the ear canals. A calibrated scale enables the head to be
centered in the machine, and orientation of the head in the Frankfort
horizontal plane was accompanied by means of a pointer to the left
orbital. This pointer lies at the same horizontal level as the top of the
ear posts. The head was locked in this position by means of a rest
which engages the bridge of the nose. Two x-ray tubes were used, one
for lateral and the other for frontal head plates. In the case of the lateral
exposure, the central ray passed along a line joining the ear posts, at
right angles to mid sagittal plane and the film. The exposures are made
at a target distance of five feet, thus ensuring that the enlargement of
the image was slight.
2.4.2 The uses of cephalometry
The cephalostat provides a means of taking standardized lateral
skull radiographs, thereby, facilitating the measurement of living
subjects. This led to the wide spread employment of cephalometrics as
an analytical tool to estimate craniofacial morphology, measure growth
changes, and predict future relationships. As diagnostic aid to evaluate
dento-facial anomalies, it clarifies the anatomic basis for malocclusion
and the changes brought about by orthodontic treatment (Moyers,
![Page 47: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/47.jpg)
47
1988).
Down (1952) stated "cephalometrics is to the orthodontist what
the dissection room is to the anthropologist and anatomist". Indeed,
cephalometrics had progressed to the point where it was no longer the
tool of research workers only, but was a necessary adjunct to a
complete and well planned case analysis from which a diagnosis may
be derived. It was not a panacea that will supplant all other methods of
analysis and answer all the orthodontists diagnostic problems, and it
can never take the place of clinical observation. But as long as the
science of orthodontics is the study of relations within the dento-facial
complex in which "all we ever find are variations, endless
variations"(Simon, 1926), then cephalometrics will be an invaluable
tool supplementing all other procedures of analysis.
2.4.3 Errors of cephalometry.
The development of cephalometries has created a need for
exactly locating an increased number of landmarks on head film. These
landmarks can be used as registration marks for measurements, or for
the superimposition of films in a series of examinations.
It is known that differences can occur when locating
cephalometric landmarks. By comparing the variation in a number of
measurements of different landmarks it was possible to conclude
which landmarks were most reproducible (Midtgard et al., 1974).
Some of the landmarks, used clinically, were located on the
![Page 48: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/48.jpg)
48
outlines of the cranium and were comparatively easy to identify due to
the sharpness in contrast of the head film. The structures of the inner
cranium were, on the other hand, often indistinct because of
summations of superimposed anatomical details (Hixon, 1956).
Bjork (1947) has mentioned three reasons for errors of method in
cephalometric measurement studies:
1. Differences between two films of the same individual.
2. Differences caused by variation of the positioning of the
landmarks.
3. Errors in the reading process.
His analysis of errors of method reveals large differences in
precision when locating different cranial landmarks. Only minor errors
in measurement have, however, been established with landmarks
which are easily identifiable. Linear errors of measurement in these
cases vary between 0.3 mm and 1.4 mm and angular errors of
measurement between 0.3 degrees and 1.6 degrees.
Richardson (1966) had two judges register cephalometric
landmarks, lines, and angles on ten cephalograms with an interval of
one week. He found that ordinary cranial landmarks have a margin of
error of less than +1 mm. Vertical deviations rise towards higher
counts when anatomical curves in the profile are involved. Horizontal
deviations have also been observed and all angular measurements have
followed the tendency to variation of the landmarks.
Double registrations of size and direction of facial growth have
shown minor deviations in a study carried out by Lundstrom (1968) in
![Page 49: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/49.jpg)
49
which forty-one pairs of twins were registered both initially and after
thirteen years. A noticeable difference in the pattern of growth has,
however, arisen depending on whether the head film has been
orientated from the anterior or posterior skull base. The conclusion has
been drawn that growth analyses based on lateral cephalometric head
film do not give a sufficiently objective picture of the character of the
growth changes.
Linder-Aronson (1970) has estimated the degree of error in
cranial distance measurements by calculating the variance of error for
the differences in distance in relation to the variance of the distance in
the material as a whole. The variety of error has, with few exceptions,
amounted to less than three per cent of the total variation.
Baumrind and Frantz (1971) have found that landmarks nasion
and menton which are placed anatomically on the bony edges are easy
to identify, whereas landmarks which are placed on curves with wide
radii show proportionally greater errors of measurement. They have
statistically concluded that the probability of placing sixteen landmarks
correctly is forty-four per cent.
Houston et al. (1986) mentioned in assessment of reproducibility
of the measurements that two types of errors should be estimated, the
systematic and random errors.
The systematic error is not easy to detect and it is associated with
the particular instruments or technique of measurement being used. It
can originate from the faulty calibration of equipment, or from bias on
the part of the observer. For example, if measurement from two
![Page 50: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/50.jpg)
50
different studies are compared and it is assumed incorrectly that the
magnification are the same, the comparison is biased. These errors
must be estimated from an analysis of the experimental conditions and
techniques. On the other hand the random error is produced by a large
number of unpredictable and unknown variations in the experimental
situation. The precision of an experiment is dependent on how well we
can overcome or analyze random errors. Example of this error is
tracing error which may be caused by the lack of clarity of
cephalometric landmarks due to superimposition of structures, or the
blurring of the image brought about by movement during exposure.
These errors can be neutralized in studies by studying a sample of
adequate size and by tracing each film more than once (Gravely and
Benzies, 1974).
2.5 Cephalometric methods of assessing skeletal
relationship.
There are different methods of assessing the degree of skeletal
discrepancy. It would be very difficult to include them all, and only the
most commonly and widely used methods will be reviewed. These
methods are:
2.5.1 ANB angle.
ANB is the most widely used method to assess skeletal
relationship. It is the result of subtracting SNA from SNB. Although it
is known as Down method, Riedel (1950) was actually the first to
![Page 51: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/51.jpg)
51
suggest using the angle ANB to measure the anteroposterior apical
base relationship. Riedel (1950) found the angle to have a mean value
of 3.4° based on a small sample of cases with good profiles (beauty
queens) rather than good occlusion. On the other hand, Steiner (1953)
found the mean value for ANB to be 2° in his analysis based on normal
occlusion
Figure 4: Illustration of the angle SNA, SNB and the subtracted ANB
angle
Although the ANB angle is used extensively in everyday clinical
practice, under the name of Down's analysis, for the assessment of the
skeletal relationship, there are some shortcomings in the method. The
ANB angle is known to be affected by the absolute value of angle
SNA, which in turn, is influenced by variations in the horizontal or
vertical position of nasion or the slope of SN plane. Rotation of the
jaws relative to the anterior cranial base also alters the position of A
and B points, and hence, the value of ANB (Richardson, 1982).
![Page 52: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/52.jpg)
52
2.5.2 Wits analysis.
The second most commonly used method is Wits analysis
(described by Jacobson in 1975). Wits is an abbreviation for the name
of Wits Watersrand University in South Africa. The method relies on
the projections of perpendiculars from points A and B onto the
functional occlusal plane at AO and BO. The horizontal distance
between the points AO and BO is found on average to have a value of
zero in females. In males AO is 1 mm behind BO.
Figure 5: Illustration of Wits Method
The main disadvantage of this method is that it lies in the
difficulty of accurately drawing the functional occlusal plane. This
has a direct effect on the reading (Brown, 1981) especially in
growing children, where the premolars are partially erupted. In
addition, to the need for magnification as a linear measurement, there
is besides the difficulty in identifying point A.
![Page 53: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/53.jpg)
53
2.5.3 A-B plane angle
The third method is described by Down (1948) as the angle
formed between the A and B planes and the facial plane (N-Pog).
Positive and negative signs were used to .denote the relative protrusion
of the mandible. The mean value of this angle was found to be minus
4.6 in a study of twenty cases with excellent occlusions.
Figure 6: Illustration of A-B plane angle
The shortcoming of this method is the influence of the horizontal or
vertical position of point nasion, and the difficulty in identifying point
A.
![Page 54: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/54.jpg)
54
2.5.4 Ballard Conversion Method
Ballard (1948) devised a method based on the incisor tooth
position for assessing skeletal pattern. This method assumes that if the
upper incisors are within the average variation of angulation to the
maxillary plane and lower incisors within the average variation of
angulation to the mandibular plane, then, the residual overjet will
approximately reflect the anteroposterior dental base relationship.
Figure 7: Illustration of Ballards Conversion Method
In the above concept, there is the basic assumption that the ideal
tooth position in relation to dental base will indicate the skeletal
relationship. Houston (1975) examined Ballard's method and criticized
it on the grounds that :
i] The relationship between the base and the developmental position
of the incisors was not invariant.
ii] There was no justification for using the mean values for the
![Page 55: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/55.jpg)
55
correction of the incisor angulation, because at best they were
only arbitrary.
iii] The classification depended upon whether the incisors were
rotated at the apex or the apical third of the root.
2.5.5 A-B/functional occlusal plane angle
Houston and Tulley (1986) described a method to assess the
anteroposterior skeletal relationship. The method uses the AB planeand
the functional occlusal plane and measure the angle formed between
the two planes.
Figure 8: Illustration of A-B/Functional occlusal plane angle.
In a class I skeletal pattern, the range was found to be 85° - 95°.
More than this value will indicate class II skeletal relationship and less
than this value will indicate class III skeletal relationship. Similar to
Wits analysis, this method is affected by any variation in the
orientation of the occlusal plane.
![Page 56: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/56.jpg)
56
2.5.6 The Archial Analysis.
The least used method is the archial analysis of Sassouni (1955).
His analysis is unique in that it does not employ a set of established
norms, but rather defines the relationships within the individual pattern
as normal or abnormal in anteroposterior and vertical directions. It is
constructed from five horizontal planes and tend to intersect a central
area "0". From this area "0" five arcs were drawn, the first one called
the anterior arc. In a class I skeletal relationship, ANS and Pog should
be located on an anterior arc. In a class II skeletal relationship, Pog is
posterior to the anterior arc, or ANS is anterior to this arc. In a class III
skeletal relationship Pog is anterior to the anterior arc, or ANS is
posterior.
Figure 9: Illustration of the archial analysis
![Page 57: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/57.jpg)
57
The shortcomings of this analysis are that:
i) the landmarks used were not easy to locate,
ii] not easily understood by everyone.
From the above, it will be seen that each method used to measure
the anteroposterior relation of the maxillary and mandibular dental
bases has its own merits and demerits. However, the first method of
analyzing skeletal discrepancy i.e. ANB angle is the one which is most
widely
adopted, and accepted by the clinician and researchers as the most
reliable method to achieve their purpose (Freeman, 1981). It has
became part of everyday clinical practice and is considered as a must
for each cephalometric analysis (Enlow, 1990).
2.6 Cephalometric Studies on Caucasian Population.
2.6.1 Cephalometric studies on normal skeletal relationship.
Baum (1951) carried out a study on 62 children. The subjects were
equally divided by sex and all had clinically excellent occlusions,
considering tooth relationships only. The mean age for the males was
12 years 8 months +1.29 months and for females 12 years 7.5 months +
1.56 months. The landmarks and planes used were those employed by
the ANB angle. He found that though the angle of convexity of the
male was higher than that of females, no other significant differences
in the skeletal or dental patterns of the sexes were to be observed.
However, when compared to Down's group, this younger group was
![Page 58: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/58.jpg)
58
shown to have more convex faces, less upright incisors in relation to
either the occlusal plane or mandibular plane and a more protrusive
denture. The author, therefore, came to the conclusion that it was
important to appreciate the differences in the skeletal and denture
patterns of adults and children.
Goldsman (1959) used 50 individuals selected by a panel for
"harmony of facial balance and proportions", which he called the
Indiana sample. This sample was found to include some convex and
some concave facial types. Every individual displayed a class I molar
relationship. When compared with Downs analysis, the measurement
of the Indiana sample were similar to those of Downs with the
exception of the facial angle and the Y-axis angle, where significant
differences existed. The range of extremes of all measurements of the
Indiana sample was wider than that of Down's sample; all of Down's
denture measurements, as well as the Frankfort mandibular planes
angle and angle of convexity had smaller standard deviations than
those of the Indiana sample who were disposed towards the
retrognathic or class 11 side of Down's findings.
An investigation involving a comparison of facial and dental
parts of children of similar ethnic origin but living in different
countries was carried out by Gresham (1963). It involved 23 males
and 21 females (Whites) living in North America and a similar group
of New Zealand children. The individuals in each group were of
similar age, sex, occlusion and ethnic origin. Quite a marked overall
similarity was found in the basic skeletal pattern. The New Zealand
![Page 59: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/59.jpg)
59
child tended to have a more obtuse saddle angle, but the effect of this
upon the facial pattern as a whole was cancelled out by the relatively
longer mandibular body in the New Zealand child. The general
relationship to the cranial base of the chin and the facial plane was,
thus, practically identical in the two groups. However, differences
were noted in facial height and the overall protrusion of the incisor
teeth which tended to be greater in the New Zealand child.
Taylor and Hitchcock (1966) introduced the 'Alabama analysis'
based on a study of 17 boys and 23 girls from the ages of 8-15 years.
A total of 32 measurements were made from the tracings of each
of the 40 subjects, out of which the authors selected 16 which formed
the Alabama analysis. Only one measurement, upper incisor to SN
plane, showed a value large enough to indicate a questionable
difference between boys and girls might have been revealed if the
sample had been larger. However, when comparing their
measurements with available data from other similar studies carried
out on American white children, 6 measurements were found to be
significantly different, which led the authors to the conclusion that they
were dealing with a different population and that the ethnic
background of Southern white children is different enough from that of
children in other sections of the country to warrant a separate
cephalometric standard. In the course of their study, Taylor and
Hitchcock also related certain cephalometric points to the Frankfort
plane and to other reference planes. In every instance, they found that
each measurement relative to the Frankfort plane showed a larger
![Page 60: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/60.jpg)
60
standard deviation or spread than the corresponding measurement to a
plane other than the Frankfort plane. Thus, they concluded that the
Frankfort plane was not reliable enough and based their analysis on the
SN line as a reference.
Cephalometric measurements on 50 English and 50 Indian adults,
equally divided as regards sex, were compared for sex and group
differences by Iyer and Lutz (1966). Evaluation of their average
measurements indicated that the female facial size was generally
smaller than the male's. The Indian face was not prognathic but was
smaller with smaller facial and gonial angles, and more proclined
lower incisors, when compared with the English. The authors also
claimed that it was possible to classify the individuals by sex, and
assign them to the Indian or English group with an 80% accuracy,
using 14 measurements. They also arrived at the conclusion that the
SN line, maxillary plane and Frankfort plane were all equally suitable
for assessing upper incisor inclination.
Christie (1977) looked at the dentofacial cephalometric patterns
of adults possessing near ideal occlusions. His sample consisted of 82
caucasian adults (43 females and 39 males), and was divided into
individuals with a vertical (dolichofacial) pattern or a horizontal
(brachyfacial) pattern. His major finding was that normal occlusion
occurs more commonly in individuals who tend to have brachyfacial
skeletal pattern. A clear trend showed that the more brachyfacial a
person, the greater the likelihood there was of their having a normal
occlusion. These individuals were shown to have a greater distance
![Page 61: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/61.jpg)
61
from the maxillary first permanent molar to the upper central incisor,
and also a greater distance from pterygoid vertical to the maxillary first
permanent molar. Because they experience more horizontal growth in
the jaws, they have larger arches and therefore less crowding,
supported by an increase in intercanine and intermolar widths. The
author felt that this may have profound implications for treatment
planning in that there may be less need for extractions in order to
achieve good occlusions.
Scheideman et al. (1980) carried out a comprehensive
cephalometric analysis of "normal" adults. Fifty six adult caucasians
with class I skeletal and dental relationships and good vertical facial
proportions were analyzed morphologically with a computerized
craniofacial model. The study was designed to establish cephalometric
norms for soft tissue, skeletal and dental relationships of a "normal"
adult population. With few exceptions, the skeletal and dental
relationships were found to be in close agreement with previous
studies.
Schmuth et at. (1988) based their study on 393 cephalograms
taken at the beginning of orthodontic treatment. The mean values of
some commonly used cephalometric angles were calculated and
compared with the corresponding values given in the literature. The
result of this comparison was that there were surprisingly small
differences between these values based on an unselected mal occlusion
group and those in the literature which were mostly based on "normal"
occlusion patients. All the parameters measured showed a high degree
![Page 62: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/62.jpg)
62
of variability.
2.6.2 Cephalometric studies of the class 11 skeletal relationship
Blair (1954) studied 40 class I subjects; 40 class 11, division I
subjects; and 20 class II, division 2, subjects. They had an age range of
10 to 14 years. The only mandibular difference was a greater gonial
angle in the class I males. There were no differences in the females.
There were no differences in mandibular position between class I and
class H. Blair noted great variation in the subjects and the possibility
of a forward position of the maxilla in class H.
Altemus (1955) based his study on 40 girls (20 class H, division
1, and 20 controls) and found that the class H maxillae were more
protrusive and that the mandibles were normal in size.
Sassouni (1969) reported the skeletal class H type could be due to
positional deviation, dimensional deviation or both of them.
Positional deviation can be viewed as a mismatching of
characteristics of the open bite and deep bite types. The skeletal class
H borrows the long anterior cranial base from the open bite, as well as
the short ramus, but the small gonial angle was from the deep bite. The
palate is tipped downward and backward as in the open bite. The result
of these combinations was a protrusive maxilla, a retrusive mandible,
or both and angle class H mal occlusion.
Dimensional deviations were due to two major disproportions,
the large maxilla and the small mandible. The large maxilla was
characterized by a palate in which the posterior nasal spine was
normal.in position but too long for the rest of the face, but the
![Page 63: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/63.jpg)
63
mandible was normal in size and position. The small mandible was the
most frequent cause of dimensional class 11 skeletal type. The corpus
was short and the gonion was in the normal position which leads a
retrusive chin. Dental crowding, ectopic eruption and impaction were
seen in these cases. The discrepancy between the maxilla and the
mandible kept the lips apart.
Hitchcock (1973) studied one hundred and nine (fifty seven
female and fifty two male) class 11, Division 1 malocclusions
documented from cephalometric head films, and compared them with
forty normal occlusion cases. The classification was made from models
and photographs according to Strang’s first six steps (1958). The age
range was from 7 years to 28 years. He found that the position of
maxilla was not significantly different from that of normal occlusion
sample (SNA), but SNB measurement was smaller in class 11 division
1 malocclusion. The ANB was greater which led to a retruded position
of the mandible. The angle of occlusal plane to SN plane in class 11
cases showed no significant difference from that measurement in the
normal occlusion sample. However, the angle of the mandibular plane
to sella nasion, and the Y- axis angle were greater in class 11, division
1, than in normal occlusion. The lower incisors showed no highly
significant difference between class 11 subjects and the normal
controls but the upper incisor to N A measurement and the overjet were
protruded in class 11, division 1 subjects, while thy lower incisors had
a normal position when compared to normal occlusion.
McNamara (1981) analyzed lateral cephalometric radiographs of
![Page 64: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/64.jpg)
64
227 children (153 males and 124 females) between the ages of 8 and 10
years, with class 11 molar and cuspid relationship. The results were
compared to norms available in the literature. He concluded that only a
small percentage of his subjects showed maxillary skeletal protrusion
while the highest percentage showed maxillary retrusion. Mandibular
skeletal retrusion was the most common feature. He also found the
degree of maxillary dental protrusion was less than that reported by
most previous investigators and the lower incisors were usually well
positioned. However, there was some dental protrusion and retrusion.
Almost half of the sample exhibited excessive vertical development.
Giorgio and Lucchese, (1982) evaluated the shape, size and
position of the mandible in class II, division 2 malocclusion based on a
sample of 60 subjects (38 male and 22 female) with class II, division 2
malocclusion, and a control sample of 28 subjects (13 male and 15
female) with normal occlusion. The age range in each sample was 9 to
14 years. By analyzing the cephalometric radiographs they found the
mandible of subjects with class II, division 2 mal occlusion tend to
have a unique skeletal pattern of the face, characterized by a hyper
development of the component parts of the mandible (ramus height and
the body) and a small gonial angle.
Amoric (1985) conducted a study of 100 French subjects and
analyzed McNamara's linear measurement for the maxilla and
mandible. He found statistically significant differences in the means
and distribution of his results. Amoric's mean was more protrusive for
point A and less retrusive for pogonion. No indication were given on
![Page 65: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/65.jpg)
65
the age of the subjects or the degree of skeletal dysplasia in the
sample. As noted by Amoric, McNamara's sample had excessive
anterior vertical dimension. Amoric's sample consisted of more
horizontal growers than McNamara's, thus leading to less mandibular
retrusion.
Sarhan and Hashim (1994) studied a random sample of 150
British school children aged 9 to 12 years. Lateral skull radiographs
were taken and traced. Out of the sample, 41 children (18 boys and 23
girls) were selected on the basis of an ANB angle> 4.5 degrees, as
having a class 11 skeletal relation. The 41 class 11 skeletal sample was
divided according to the value of SNB angle into subjects with normal
anteroposterior positioned mandible (SNB >76°, 19 children) and
retruded mandibles (SNB <75.5°, 22 children). 16 angular and 8 linear,
skeletal and dental parameters were used. They found the retruded
mandibles had retruded maxillas with retruded chins, increased vertical
development and facial height, normal proclination of lower incisors.
The normal mandibles were characterized by protruded maxillas with
protruded chins, decreased vertical relationship and normal facial
height, and the anterior proclination of lower incisors.
Rosenblum (1995) studied 103 (36 male and 67 female) subjects
with class 11 skeletal pattern which was assessed by Down (1948)
angle of convexity and the Kim (1978) anteroposterior dysplasia
indicator (APDI). Age selection was based on skeletal maturity
assessment method used by Fishman (1979). The skeletal age was
divided at three levels of skeletal maturation (SMI 1-3, SMI 4-7, SMI
![Page 66: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/66.jpg)
66
8-11). Chronological age ranged from 12 - 16 years. He found that the
dominant pattern was maxillary protrusion with normal mandible. The
angle NA-FH (Lande 1952) indicated the incidence of maxillary
protrusion in the three groups was 56.3%. Using N-A to FH as
reference showed that SNA (Steiner, 1953) under - reported maxillary
protrusion 39 % of the time, but the reporting of A to nasion
perpendicular (McNamara, 1984) was close at 53.5%. The facial angle
(Down, 1948) indicated that only 26.7% had mandibular retrusion.
Using the facial angle for mandible as reference showed that SNB over
- reported mandibular retrusion 46 % of the time and Pog to nasion
perpendicular (McNamara, 1984) over reported this 40% of the time.
2.6.3 Cephalometric studies of the class III skeletal relationship.
Bjork (1947) conducted a study on 281 Swedish conscripts
between the ages of 21 and 23 years. Twenty six cases presented class
III skeletal relationship. These were compared to the whole sample on
the basis of mean values. He found that the maxillary base was slightly
more
retrognathic than the mean value for the whole material. The
mandibular base was slightly more prognathic. The maxillary incisors
showed an average forward inclination and the mandibular incisors a
backward inclination. There was a reduction in the saddle and joint
angles and a shortening of the vertical part of the cranial base (sella-
articulate). These were accompanied by a shortening of the cranial
base from nasion to articulare. He found also that in the class Ill, the
![Page 67: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/67.jpg)
67
mandible had a greater gonial angle, a more acute angle was formed
by the occlusal plane with the lower border of the mandible, and there
was a narrower antero- posterior width of the ramus.
Stapf (1948) studied 37 class III facial patterns without regard to
age, sex, or severity of deformity. The mean pattern was compared to
that of 21 individuals, eight years of age, with normal occlusion. In the
class III pattern, the posterior end of the occlusal plane was lower and
the anterior end higher than in the normal. The angle formed by
symphysis and lower border of the mandible was more acute.
Sanborn (1955) made an excellent cephalometric study of 42 (26
males and 16 females) class III skeletal relationship adult patients
compared to 35 (26 males and 9 females) adult controls, age ranging
from 16 to 38 years. He found that for the angular measurements, the
class III facial pattern showed a middle face deficiency and more
prognathic mandible than the normal, resulting in a concave profile
which was a most striking feature of the class In deformity. The ramus
of the mandible in the class III group formed a more acute angle with
anterior cranial base and upper face than is normal, which had the
effect of positioning the gonion further forward. The gonial angle was
more
obtuse and the lower border of the mandible more steeply inclined. He
further found no significant difference between the two samples in the
mean length of the ramus from articulare to gonion, nor the mean
length of the body of mandible from gonion to gnathion and also no
significant difference in the angular relationship between the horizontal
![Page 68: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/68.jpg)
68
planes, anterior cranial base, Frankfort, palatal and occlusal planes.
Horowitz et al. (1969) undertook a study of lateral cephalograms
of 52 subjects (30 males and 32 females), 17 years of age or older, who
satisfied these criteria:
a) Lower portion of the face was prominent.
b) The presence of class III angle malocclusion, 36 individuals
showing deep bite and the rest anterior open bite.
The sample was compared with 30 untreated class I (angle)
occlusion subjects. He concluded that a high negative difference was
observed between the mandibular and maxillary apical bases (ANB).
The relationship of the mandibular apical base and mandibular body to
the cranium was greater m the prognathism subjects, indicating a more
forward positioning of the entire mandible (SNB). The mandibular
ramus position relative to the cranial base was smaller in the class III
group, reflecting forward positioning of the mandible relative to the
cranium (saddle angle). The relation of the ramus and body of the
mandible (the gonial angle) was largest in the open bite group and
intermediate in the deep bite group. The anterior portion of the
mandible was larger in prognathism groups. The position of maxilla
showed no difference (SNA). Maxillary length was smaller in
prognathism groups. Both anterior cranial base and the posterior
cranial base were shorter. The posterior face height was shorter in
prognathism groups, but there was no difference in anterior face height
in the deep bite and control groups, while it was significantly longer in
the open bite group.
![Page 69: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/69.jpg)
69
Sassouni (1969) found that the class III skeletal relationship
could be associated with the characteristics of two types of vertical
disproportions (the skeletal deep bite and open bite). The constitution
of this skeletal type may be due to a dimensional or a positional
imbalance or both, and each type has its own characteristic features.
Class III skeletal type due to position deviation had the
characteristics of open bite and deep bite types. In common with deep
bite, it had small cranial base angle which brings the glenoid fossa and
therefore the condyles anteriorly relative to sella turcica. The mandible
was typical of the open bite of large gonial angle. The palate was
tipped upwards at PNS and downward at ANS which brings the
maxillary molar to the higher level. The end result of this set was
maxillary retrusion, mandibular protrusion, or both.
Class III skeletal type due to dimensional deviation which could
be either micromaxilla or macromandible. Micromaxilla had a short
constricted palate transversally, with crowding of the maxillary dental
arch. It showed impaction, the congenital absence of some teeth or
ectopic eruption of molars and a narrow nasal aperture.
Macromandible was due to the excessive length of mandible that might
be located at the condyles, the ramus, or the corpus. Seldom was the
mandible excessive in anteroposterior length without the breadth being
large. The chin was pointed and there was a long styloid process.
Dietrich (1970) studied a sample of 172 untreated skeletal class
III cases who had negative ANB angle, compared to 111 untreated
skeletal class I cases and divided it into three groups: deciduous, mixed
![Page 70: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/70.jpg)
70
and permanent dentition. The age ranged from 3 to 17 years. The
results showed that the class III skeletal relation can be presented as
follows: mandibular prognathism cases which are characterized by an
SN A angle within the average normal range and an SNB angle greater
than the mean value. The saddle angle was significantly smaller in all
age groups with mandibular prognathism. The Y-axis angle was
significantly smaller in all age groups with mandibular prognathism.
The angle formed by the maxillary and mandibular planes was
significantly smaller only in the deciduous dentition group of
mandibular prognathism. The gonial angle was enlarged to a
significant degree only in the permanent dentition group of mandibular
prognathism. The lower incisors were significantly retruded in the
mixed and permanent dentition groups of mandibular prognathism
while the upper incisors were protruded. The length of the body of the
mandible, expressed by the linear measurement Gn-Go, was slightly
greater in the mandibular prognathism groups, without exhibiting a
statistically significant difference.
Maxillary retrognathism cases were characterized by an SN A
angle smaller than the mean value of the corresponding control group
and an SNB angle within the average normal range. The angle formed
by the maxillary and mandibular planes was significantly enlarged
only in the permanent dentition group. The gonial angle was
significantly enlarged in the mixed and in the permanent dentition
group. The lower incisors were significantly retruded in all groups of
maxillary retrognathism. The length of the maxilla, expressed by linear
![Page 71: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/71.jpg)
71
measurement A-PNS was significantly reduced in all age groups of
maxillary retrognathism.
Ahlgren (1970) carried out study on a sample of 12 male and
female patients having angle class III malocclusion. The mean age was
17.8 (14-22 years old). All had full records including casts, lateral
cephalograms and electromyograms.
The cephalometric measurements showed distinct skeletal class III
relationship features, indicated by a negative ANB angle. The
explanation of the skeletal class III pattern lay both a protruded
mandible, indicated by an abnormal high value of the SNB, and a
retruded maxilla, indicated by a small SNA. Another significantly
different value was the gonion angle. The dental values indicated that
the lower incisors were retruded while the upper incisors tended to be
protruded.
Jacobson et al. (1974) carried out a study on pre-treatment lateral
cephalometric radiographs of 149 patients with class III malocclusion,
the sample comprised of sixty six adults, and eighty three children,
males and females (age range 6 to 16 years) and those films were
compared to 112 males and females with a normal occlusion (age
range 6 to 16 years). They found that the most significant difference
between adult sample of class III and normal occlusion was the ANB
angle, which may be attributed principally to the class III mandible
being more prognathic. Also contributing to this difference was the
shorter anterior cranial base in class III mal occlusion which in turn
tends to effect a relative maxillary deficiency. A further contributory
![Page 72: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/72.jpg)
72
factor toward the class III skeletal relationship was a more obtuse
gonial angle, associated with a straight line morphology while the
glenoid fossa was located forward. They also found the differences in
the dental parameters appeared to have a compensatory response. They
concluded the differences comparing craniofacial and dental patterns
between child and adult class III skeletal relationship as follows: As
growth in class III malocclusion carried point B forward, the ANB
angle was increased, the lower incisors became upright, and the upper
incisors procline. Little effective growth rotation appeared to take
place, since the mandibular plane did not change significantly. Sexual
dimorphism was mainly reflected in the larger male class III mandible.
Although the craniofacial proportions of male and female class III
cases were similar, females tended to have a slightly more divergent
type of pattern.
Williams and Andreson (1986) did a cephalometric study on a
group of 24 (13 girls, 11 boys) class III skeletal relationship children
with an average age of 11 years (ranging 9 years to 12 years) who at
the cessation of growth (confirmed on hand/wrist films), exhibited a
sagittal jaw relationship judged by Wits analysis to be less than 4.mm.
The control group consisted of 33 children (16 boys, 17 girls) with
average age of 11 years (range 10 years to 11 years). They identified
the following characteristics in the growing child that could indicate
development of class III skeletal relationship: a reduction in maxillary
length and anteroposterior position relative to point sella were observed
in class III material whereas vertical dimension showed no significant
![Page 73: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/73.jpg)
73
difference in class I material, neither anteriorly nor posteriorly.
The length of the mandible revealed that on average no difference
existed between the two groups. The sagittal position of the points
pogonion and B were placed more anteriorly and the distance
indicating sagittal position of the glenoid fossa relative to sella was
reduced in class III group. There was no significant difference in ramus
height between Group I and III. The ratio between maxillary and
mandibular lengths was reduced in class III material. On average the
Wits analysis for class III group was greatly reduced.
Guyer et al. (1986) conducted a cephalometric study of 143 (72
males, 71 females) class III malocclusion compared to 128 class I
controls (64 males, 64 females). The age range from 5-15 years. They
found that class III can be identified by various combination of skeletal
and dental components. Simple maxillary retrusion was found in 25 %
of the total sample, while mandibular protrusion, which was cited as
the major skeletal aberration in individuals with class III malocclusion,
was found in only 18.7% of the total sample. A combination of
maxillary retrusion and mandibular protrusion was found in 22.2 % of
this sample. 41 % of this entire sample had long lower face height.
They also found that the average characteristics of class III subjects
were as follows: the posterior cranial base length, was longer. The
effective length of class III maxilla was short while the position was
generally retrusive. The sagittal mandibular skeletal position was
prognathic, while the length was long.
The gonial angle was more obtuse. The mandibular plane angle
![Page 74: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/74.jpg)
74
tended to be greater. There was greater vertical lower face height in
class Ill. Maxillary incisors were significantly protrusive and
mandibular incisors were retroclined.
Hashim and Sarhan (1993) conducted a study on a random
sample of 150 British school children age 9-12 years. Out of the 150
children, 27 lateral radiographs, 12 girls and 15 boys average age 10.5
years were selected on basis of an angle ANB < 10 indicating class III
skeletal relationship. The 27 subjects were further divided on the basis
of the angle SNB as having either a normal or protruded mandible.
They found that for the antero posterior position of the maxilla, the
value of SN A was less than the mean for normal mandible, while for
protruded mandible it was more than the mean. The cranial base angle
NSA for normal mandible approached the mean value but for
protruded mandible it decreased. The gonial angle had no difference
between the two groups. The Y-axis angle was decreased in patients
with protruded mandibles than normal. SN-mandibular plane angle was
increased for subjects with normal mandibles and decreased for
subjects with protruded mandibles. SN occlusal plane angle was within
normal range for normal mandible while it was decreased for protruded
mandible. Subjects with normal, mandible had a shorter distance for
Ar-S than those with protruded mandible. The position of upper
incisors to A-pog line was protruded for normal mandible, while those
with a protruded mandible had normally positioned upper incisors.
![Page 75: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/75.jpg)
75
2.7 Cephalometric studies in Saudi Arabia.
The Saudi Arabian population living in the Arabian Peninsula
had not been previously exposed to any extensive cephalometric
research to determine the degree of skeletal discrepancy. However, the
literature revealed that a few studies were conducted to assess facial
types and malocclusion.
Jones (1987) conducted a study on 132 subjects of consecutive
patients attending to orthodontic clinic in Riyadh. The age ranges
between 5 and 32 years for the females, and between 6 and 29 years of
age for males. They were examined for occlusal relationship and
crowding. The dental malocclusion were found to be class I, 53.8 %;
class Il division 1, 28.8%; class Il division 2, 4.5%; and class Ill,
12.9%. The survey of crowding was 67.4 %. In the same paper another
study was reported on a subgroup of 69 patients from the above 132
subjects who underwent orthodontic treatment. This was undertaken to
assess the skeletal discrepancy by analyzing their cephalometric
radiographs. He found the skeletal pattern as follows: class I skeletal
relationship was 46.6%, class II skeletal 27.5 % and class III skeletal
26.1 %. In addition to these interesting findings, he also found that in
comparison with other populations there was a tendency for
bimaxillary proclination, dento alveolar compensation and greater
proportion of class III than in Western communities.
Shalhoub et al. (1987) carried out a study for adult Saudi
Arabians to derive cephalometric norms for orthognathic surgery.
Lateral cephalometric radiographs were taken for 48 Saudi adult
![Page 76: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/76.jpg)
76
patients (24 males, 24 females) with an age range from 20 to 46 years.
All showed normal dental relationship, with no severe antero posterior,
vertical, or transverse skeletal discrepancies. Angular and linear
measurements were recorded and compared to a similar sample of
North American caucasians. They established cephalometric values for
male and female Saudi and the differences between them and North
American sample. The differences indicated that the Saudi female
demonstrates a protrusive maxilla, midfacial prominence, and a short
mandibular length and greater forward rotation of the mandible and
lesser amount of overbite while the Saudi male had a more protrusive
midface and lesser amount of overbite.
Sarhan and Nashashibi (1988) carried out a study on a randomly
selected sample of 50 Saudi boys aged from 9 to 12 years with no
orthodontic treatment to derive cephalometric .standards for Saudi
boys. Lateral skull radiographs had been taken with teeth in occlusion.
The Saudi sample was compared with a British sample aged 9-12
years. They found that there was a difference between the two samples.
Generally, the Saudi sample demonstrated a slightly prognathic face,
more protrusive upper and lower incisors, and low gonia I and saddle
angles.
Toms (1989) studied records of 500 consecutive Saudi Arabian
patients with an age range from 10-21 years (mean age 13.7 years)
referred for orthodontic treatment. The subjects were examined
clinically and radiographically for skeletal discrepancy to determine
the percentage of class III malocclusion. He found that class III
![Page 77: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/77.jpg)
77
malocclusion represented 9.4 % of the whole sample. Mandibular
prognathism was a commoner feature of class III skeletal discrepancy
than maxillary retrognathism. When investigating the characteristic
features of class III malocclusion compared to those of the control
groups, the saddle angle was reduced, maxillary length was small and
the maxillary and mandibular plane angles also reduced. On the other
hand, the gonial angle, anterior and posterior facial heights and
mandibular length were significantly large. He also found that the
upper and lower incisors exhibited a marked degree of dento alveolar
compensation for the underlying skeletal relation.
Nashashibi et al. (1990) investigated the cephalometric standards
of Saudi boys based on Steiner's analysis. The sample consisted of 55
healthy Saudi boys who were selected from different schools in
Riyadh, with a mean age of 12 years. The criteria for sample selection
was made as the basis of normal occlusion, balanced and pleasing
profiles with facial symmetry. Lateral skull radiographs were taken and
measured. The results were compared to similar studies conducted on
other ethnic groups. They found that the Saudi boys differed from
other racial and ethnic groups in some skeletal and dental
measurements. Generally, the Saudi boys revealed a more protrusive
maxilla and double dental protrusion.
It is clear that the few studies conducted in Saudi Arabia (lones,
1987; Shalhoub et al., 1987; Toms, 1989) generally showed that there
was a tendency for Saudis to have a degree of bimaxillary protrusion,
increased lower facial height with more incidence of class III
![Page 78: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/78.jpg)
78
malocclusion .
2.8 Incidence of skeletal discrepancy.
Searching the literature shows very few studies reported the
incidence of skeletal discrepancy in a population. On the other hand
numerous studies have been carried out to show the incidence of
malocclusion (Gardiner, 1982; Farawana, 1987). Generally, an
approximation of the incidence of skeletal discrepancy may be
obtained from the incidence of dental malocclusion, which is the
occlusion roughly associated with skeletal relationship, even though
the figures obtained have shown little agreement with each other. This
may be due to various factors including differences in the criteria of
selection, methods of assessment, ages and size of sample (most
methods of assessment were based upon Angle's classification normal
and malocclusion). Some of the surveys that have been carried out are
listed in Table 2.8.1. These surveys showed the incidence of dental mal
occlusion in various Caucasian samples.
When comparing the studies with each other, a wide variation was
noted in the various types of malocclusion. For class I mal occlusion
the variation ranged from 93.5 % (Gardiner, 1956) to 25.1 %, (Goose
et al., 1957), whereas, for class II malocclusion from 8.0% (Gardiner,
1956) to 35.0% (Luffingham and Campbell, 1974), and for class III
malocclusion from 0.5% (Brehm and Jackson, 1961) to 12.9% (Jones,
1987).
![Page 79: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/79.jpg)
79
Table 2.8.1: Survey of the incidence of malocclusion based on angle’s and incisor classification
Investigators Date Country Sample Age Normal Class Class Class
Number Group I II III (Yrs)
Sclare 1945 England 334 12 40.5% 30.0% 27.0% 1.0%
Bjork 1947 Sweden 322 12 26.4% 51.8% 18.9% 2.8%
Massler and Frankel 1951 USA 2,758 14-18 21.1% 50.0% 20.0% 9.0%
Gardiner 1956 England 1,000 6-15 25.0% 66.0% 8.0% 1.0%
Goose, Thompson and Winter 1957 England 935 11-12 55.3% 25.1 % 15.7% 3.7%
Haralabakis 1957 Greece 592 19-30 37.9% 36.3% 23.1% 2.5%
Hill, Blayney and Wolf 1959 USA 1,888 12-14 52.6% 33.5% 12.75% 1.1%
Brehrn and Jackson 1961 USA 6,328 6-17 16.6% 60.1 % 22.8% 0.5%
Ernrich, Brodie and Blayney 1965 USA 13,475 12-14 54.0% 30.0% 15.0% 1.0%
Haynes 1970 England 1,185 11-12 26.85% 50.3% 19.5% 2.5%
Luffingham and Campbell 1974 Scotland 269 14 - 57.0% 35.0% 8.0%
Gardiner 1982 Libya 479 10-12 - 77.0% 18.0% 5.0%
Farawana 1987 Iraq 200 6-24 - 59.6% 29.6% 10.8%
Jones 1987 Riyadh,
KSA 132 5-32 - 53.8% 33.3% 12.9%
![Page 80: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/80.jpg)
80
It can be observed from the previous table (Table 2.8.1). Saudi
Arabian sample had the highest reported incidence of class III
malocclusion among all the samples. The highest reported value was 10.8
% and the lowest was 0.5 %, whereas, for the Saudi sample, it was 12.9%.
In case of class II malocclusion, the Saudi samples had 33.3 % (J ones,
1987) whereas, for Scots had 35.0 %. In case of class I malocclusion, the
Saudi sample had 53.8% and the English had 66.0% (Gardiner, 1956)
Another search through the literature was done to identify the
incidence of the skeletal discrepancy and its distribution among
Caucasians. It showed unfortunately that very few studies were conducted
to report the incidence of skeletal discrepancy. The findings of the
available literature were summarized in Table 2.8.2.
Walther (1960) carried out a research project which consisted of
random sample of 1000 children selected according to the following
criteria.
1. The age ranged between 11 and 13 years
2. They all came from secondary schools in East Anglia, UK.
3. One third of the children were taken from each school.
![Page 81: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/81.jpg)
81
Table 2.8.1: Survey of the incidence of skeletal discrepancy classification
Investigators Date Country Sample
Number
Age
Group
(Yrs)
Skeletal
I
Skeletal
II
Skeletal
III
Walther 1960 England 1,000 11-13 35.6% 53.3% 11.1%
Foster and Day 1974 England 1,000 11-12 40.8% 53.8% 5.4%
Luffingham and Campbell 1974 Scotland 269 14 55.0% 29.0% 16.0%
Salvicek, Schadldauer and Schrangl 1983 Austria 2,275 Adult 37.2% 51.8% 11.1%
Farawana 1987 Iraq 200 6-24 74.5% 13.0% 10.0%
Jones 1987
Riyadh
Saudi
Arabia
69 5-32 46.4% 27.5% 26.1%
![Page 82: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/82.jpg)
82
The study was conducted to find out the causes and effects of
malocclusion. By the clinical assessment of skeletal relation and by using
Ballard's method, he found that out of the 1000 cases: 35.6% had class I
skeletal relationship; 53.2 % skeletal Il relationship; whereas, skeletal III
was 11.1 %.
Foster and Day (1974) did a study on 1000 Shropshire children,
aged 11 to 12 years of age, with the objective of assessing some occlusal
features and the need for orthodontic treatment. The children examined
were first year pupils in secondary school, with equal number of girls and
boys. They found that the skeletal relationship as an etiological factor
which was assessed clinically by Ballard method to be: 40.8% having class
I; 53.8 % class II: and only 5.4 % class III.
Luffingham and Campbell (1974) examined 269 children of whom
127 were male and 142 female. The sample involved were all secondary
school students with a mean age of 14 years. The antero-posterior jaw
relationship was assessed clinically. The patients were viewed in profile
with the Frankfort plane horizontal and points A and B were palpated.
They found that skeletal class I comprised 55 %, skeletal class II, 29% and
skeletal class III, 16%.
Farawana (1987) studied 200 persons attending the Orthodontic
Department at the College of Dentistry (Baghdad), to determine the
features of mal occlusion among the Iraqi population. The skeletal relation
was assessed clinically, based on Broadbent's classification and
radiographically according to the ANB angle (a larger angle than normal
would indicate a class II skeletal relation, while a negative ANB would
![Page 83: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/83.jpg)
83
indicate a class III skeletal relationship). She found that the predominant
skeletal relationship in the Iraqi patients was class I. It formed 74.5 %,
while class II formed only 13 % and class III only 10% of the sample.
Jones (1987) conducted a study on two separate samples of patients
attending orthodontic clinic in Riyadh. The age ranged from 5-32 years for
females and between 6 and 29 years for males. They were examined for
occlusal relation, and crowding. In the same paper another study was
reported on a subgroup of 69 patients offered treatment from the above 132
subjects to assess skeletal discrepancy using cephalometric radiographs. He
found that the skeletal pattern were as follows: class I skeletal was 46.4 %,
class II skeletal 27.5 % and class III skeletal 26.1 %.
However, this study was based on patients selected for orthodontic
treatment so it would be unwise to extrapolate this figure to the whole of
the Saudi population in view of the biased nature of the sample and its
small number (J ones, 1987).
![Page 84: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/84.jpg)
84
3.0 STATEMENT OF THE PROBLEM AND PURPOSE OF THE STUDY
![Page 85: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/85.jpg)
85
3.0 Statement of the problem and purpose of the study.
Skeletal discrepancies can lead to limitation for orthodontic
treatment. For proper diagnosis and treatment planning, such
discrepancies need to be known for each racial group of the human
population. The skeletal characteristics and classification in some ethnic
groups were documented, such as Chinese by Chan (1972), North
American Whites by Riolo et al. (1974), Negro by Fonseca and Klein
(1978) and British Caucasians by Bhatia and Leighton (1993).
In Saudi Arabia, the classification and characterization of skeletal
discrepancies are still not well covered. Although there have been few
studies (Jones, 1987; Toms, 1989) but these studies lacked randomness
and an adequate sample.
It was clear that there was a great need to conduct a study to
investigate in more detail the characteristic features of the various skeletal
classes in Saudi Arabia.
3.1 The Aims of the Present Study.
1. To investigate the various types of skeletal classes in a group of
female school children in Saudi Arabia.
![Page 86: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/86.jpg)
86
2. To investigate the cephalometric skeleto-dental characteristic
features of class II and class III skeletal relationship compared to
class I.
3. To compare the cephalometric skeleto-dental results of class I of
the Saudi sample to the established Caucasian cephalometric
standards.
In achieving the aims, the following hypotheses will be
subjected for testing.
A. As Saudi Arabian population belongs to Caucasian, then they
should have similar skeleto-dental characteristics.
B. The skeletal discrepancies of class II and class III skeletal
relationship were attributed mainly to a positional and/or
dimensional cause.
![Page 87: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/87.jpg)
87
4.0 Materials and Methods
![Page 88: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/88.jpg)
88
4.0 Materials and Methods.
4.1 Materials.
The sample used in the present study consisted of 205 lateral skull
radiographs of Saudi female school children which were derived from a
large sample (5112 subjects) conducted in Jeddah, Saudi Arabia (Masoud
et al., 1994). The age range of the subjects were between 10-12 years with
a mean age of 11 years and a standard deviation of 1 year. Lateral skull
radiographs were taken with the head in natural head position.
4.1.1 Criteria for Sample Selection were as follows:
The following criteria were applied to select 205 cephalometric
readiograph from the large sample of 850 subjects.
1. The radiographs should be of high quality.
2. The first permanent molars should be in occlusion.
3. There should have been no previous orthodontic treatment.
4. There should be no cleft or craniofacial deformities.
5. The age of the individuals should be between 10 and 12 years old.
![Page 89: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/89.jpg)
89
4.1.2 Tracing Technique.
The radiographs were traced under standardized procedure using sharp 3H
lead pencil on fine acetate tracing papers. This was performed in a
darkened room to obtain maximum contrast and to facilitate landmark
identification. Bilateral structures giving double images e.g. gonion and
articulare, the mid-point was chosen.
4.1.2.1 Cephalometric Landmarks.
The following landmarks were identified and recorded in sequence.
Planes and lines were drawn, then angular, linear, and proportional
measurements were obtained.
4.1.2.1A Definition of the Landmarks
Landmarks Abbreviations Description
1) Sella S The mid-point of the sella turcica
2) Porion Po The upper most outermost point on
the bony external auditory meatus
3) Basion Ba The most posterior inferior point on
the Clivus. It lies on the anterior
margin of foramen magnum
![Page 90: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/90.jpg)
90
Landmarks Abbreviation Description
4) Hinge Axis HA The center of the condyle
5)
Pterygoid
point
Pt
A point is located on the
posterior-superior border of
the pterygo-maxillary fissure.
It identifies the place of
emergence (foramen
rotundum) of the maxillary
nerve from the cranial base.
6) Nasion N The most anterior point on the
fronto-nasal suture
7)
Orbitale
Or
The most inferior anterior
point on the margin of the orbit
8) Anterior nasal
spine ANS
The tip of the anterior nasal
spine
9) Posterior nasal PNS The tip of the posterior nasal
spine spine
10)
Point-A
A
The most posterior point on
the profile of the maxilla
between the anterior nasal
spine and alveolar crest
11)
Point-B
B
The most posterior point on
the profile of the mandible
between the chin point and
alveolar crest
12) Reversal Zone RZ It is the reversal zone
between two growth fields
where the concave surface
contour becomes convex
(Enlow 1990)
![Page 91: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/91.jpg)
91
Landmarks Abbreviations Description
13) Pogonion Pog The most anterior point on the
bony chin
14) Menton Me
The lowest point on the lower
border of the mandibular
symphysis
15) Posterior
ramus PRM2 The most prominent posterior
Point-2 superior point at the angle
of the mandible on the ramus
16) Mandibular base MBI The most inferior point on the
Point-l lower border of the mandible
behind the antigonial notch
17)
Articulare
Ar
The point of intersection
between the posterior border of the mandibular condyle and
lower border of the cranial
base
18) Upper Incisor UIE The tip of the most prominent
edge upper incisor crown
19) Upper Incisor UIA The root apex of the most
Apex prominent upper incisor
20) Lower Incisor LIE The tip of the most prominent
Edge
Lower Incisor
lower incisor crown
21)
LIA
The root apex of the most
prominent lower incisor
22) Occlusal Point Oc The mid-point in the occlusal
space between: the upper and
lower first premolars
![Page 92: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/92.jpg)
92
These points are illustrated in Figure 10.
Landmarks Abbreviations Description
23) Upper Molar UDC The posterior contact (height
Distal Contact of contour) of the maxillary
Point. first
molar
24) Lower Molar LDC The posterior contact point of
Distal Contact the mandibular first molar
Point
25) Upper Molar UDR Distal buccal root of the
Distal Root maxillary first molar
26) Lower Molar
Distal Root LDR
Distal root of the mandibular
first molar
![Page 93: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/93.jpg)
93
Figure 10: Illustration of Cephalometric landmarks
![Page 94: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/94.jpg)
94
4.1.3 Digitization
The identified landmarks were digitized in a predetermined sequence
using digitizer linked to Mackintosh SE computer.
Figure 11. Illustration of the computer and the digitizer used.
Each radiograph was digitized by the investigator. The digitized
points were stored as X and Y coordinates in the computer memory. From
these coordinated new landmarks, planes and lines were derived
automatically and plotted on the monitor. From these, angular and linear
measurements can be calculated and presented for analysis. In addition to
the previous landmarks, new constructed landmarks planes and lines were
used in the present study.
![Page 95: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/95.jpg)
95
4.1.3.1 Constructed landmarks
Gnathion Gn The most anterior inferior point on the
mandibular symphysis
Gonion Go The most posterior inferior point on
the angle of the mandible
Condylion Co The most superior posterior point of
the mandibular condyle
The above constructed landmarks are illustrated in Figure 12.
Figure 12: Illustration of constructed cephalometric landmarks
![Page 96: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/96.jpg)
96
4.1.3.2 Cephalometric Planes and Lines.
From the coordinates, horizontal and vertical planes and lines were
constructed.
4.1.3.2.A The Horizontal Planes.
1) Sella-Nasion Plane SN A plane joining sella to nasion
and represented by the anterior
cranial base
2) Frankfort Horizontal FH This plane passes through points
porion and orbitale
3) Occlusal Plane Occ A plane passes through the
occlusion of the premolars or
deciduous molars and first and
permanent molars
4) Mandibular Plane MP It is defined by two ways: A
plane joining gonion to menton
and a plane joining gonion to
gnathion.
MP1 = Go - Gn
MP2 = Go - Me
The above horizontal planes are illustrated in Figure 13.
4.1.3.2.B The Vertical Planes and Lines
1) The Facial Plane Fp A plane joining the nasion pogonion
and used to assess the
facial profile
2) Y-Axis Plane Y-axis plane joining sella to gnathion
![Page 97: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/97.jpg)
97
Figure 13: Illustration of horizontal cephalometric planes
![Page 98: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/98.jpg)
98
3) Facial Axis plane F-axis A plane joining pterygoid gnathion
4) Ramal Plane Rm A plane joining A point to B point
5) A-B Plane A-B A plane joining A point to B point
The above vertical planes and lines are illustrated in Figure 14.
4.1.3.3 Angular Measurements
From the digitized points, 18 angular measurements were obtained.
These were:
1) SNA angle
SNA = the angle subtended by the SN plane and point
A.
2) SNB angle
SNB = the angle subtended by SN plane and point B.
3) ANB angle
ANB = the difference between angles SNA and SNB.
4) Angle of convexity
A-N- Pog = the angle subtended between facial plane and
the line joining points A and N.
5) Facial angle
FH/Fp = the inferior inside angle subtended by the
Facial plane and Frankfort plane.
6) AB plane angle
Fp/AB = the angle subtended by the line joining
points A and B and the facial plane.
![Page 99: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/99.jpg)
99
Figure 14: Illustration of vertical cephalometric planes
![Page 100: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/100.jpg)
100
7) Saddle angle
N-S-Ar = The angle subtended by the SN plane and
the line joining sella to articulare.
8) Gonial angle
Ar-Go-Me = The angle subtended by the Ramal plane
and mandibular plane.
9) SN/Occ = The angle subtended by the SN plane and
occlusal plane.
10) SN/MP1 = The angle subtended by the SN plane and
mandibular plane (Go-Gn).
11) FH/Occ = The angle subtended by the Frankfort
plane and occlusal plane.
12) FH/MP2 = The angle subtended by the Frankfort
plane and mandibular plane (Go-Me)
13) Y-Axis angle
FH/Y-Axis = The angle subtended by the Frankfort
plane and Y-axis plane.
14) Facial-Axis angle
F-Axis/NBa The angle subtended by the F- Axis plane
and the line joining points N and Ba.
15) Lower incisor to MP2 angle
LIA-LIE/MP2 = The angle between the long axis of the
lower incisor and the mandibular plane
(Go-Me).
16) Upper incisor to NA angle
UIA-UIE/NA = The acute angle formed by the long axis
of the upper incisor and the line N A.
17) Lower incisor to NB angle
LIE- LIA/NB = The acute angle formed by the long axis
of the upper and lower incisors.
![Page 101: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/101.jpg)
101
18) Interincisal angle
LIE-LIA/UIE-UIA = The angle formed by the long axes of the
upper and lower incisors.
The above angular measurement is illustrated in Figures 15, 16, 17.
4.1.3.4 Linear Measurements
Also from the digitized points 17 linear measurements were
obtained:
1) Point A to Nasion Perpendicular
A/N ┴ FH = The horizontal distance in mm from point
A to the vertical line extended inferiorly
from Nasion perpendicular to the
Frankfort plane.
2) Pogonion to Nasion Perpendicular
Pog/N ┴ FH = The horizontal distance in mm from
Pogonion to the vertical line extended
inferiorly from nasion perpendicular to
the Frankfort plane.
3) Mid-facial length
Co - A = The horizontal distance in mm from
condylion to point A.
4) Mandibular length
Co - Gn = The distance in mm from condylion to
Gnathion.
5) Mandibular body length
Go - Me = A horizontal distance in mm from Gonion
to Menton.
![Page 102: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/102.jpg)
102
Figure 15: Illustration of angular measurements of anteroposterior skeletal
relationship
![Page 103: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/103.jpg)
103
Figure 16: Illustration of angular measurements of vertical skeletal
relationships
![Page 104: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/104.jpg)
104
Figure 17: Illustration of angular measurements of dental relationships
![Page 105: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/105.jpg)
105
6) Pog/NB = The horizontal distance in mm from
Pog to line joining N, B points.
7) Anterior cranial base
N - S =
The horizontal distance in mm from
Nasion to Sella.
8) Posterior cranial base
S - Ar =
The distance in mm from Sella to
Articulare.
9) Ramus height
Ar - Go =
The distance in mm from
Articulare to Gonion.
10) Posterior facial height
S - Go =
The distance in mm from Sella to
Gonion.
11) Total anterior facial height
N - Me=
The distance in mm from Nasion to
Menton.
12) Lower anterior facial height
ANS - Me =
The distance in mm from Anterior
nasal spine to Menton.
13) Upper incisor to NA
UIE/NA =
The horizontal distance in mm from
the tip of the upper to the NA line.
14) Lower incisor to NB
LIE/NB =
The horizontal distance in mm from
the tip of the lower incisor to the
line NB.
15) Upper incisor A-Pog line
UIE/A Pog =
The horizontal distance in mm
from the tip of the upper incisor
to theline A-pog.
![Page 106: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/106.jpg)
106
16) Upper incisor to A ┴ FH
UIE/A ┴ FH = The horizontal distance in mm
from facial surface of the upper
incisor to the vertical line passed
through point A parallel to Nasion
perpendicular to the Frankfort
plane.
17) Lower incisor to A-Pog
LIE/A Pog = The horizontal distance in mm from
facial surface of the lower incisor to
the line A-Pog.
The above linear measurements are illustrated in Figures 18 and 19
4.1.3.5 Proportional measurements
Only two proportional measurements were obtained from the digitized
points:
1) S - Go/IN - Me = The posterior facial height as
a percentage of total anterior
facial height.
2) ANS - Me/N -Me = The lower anterior facial height
as a percentage of total anterior
facial height.
![Page 107: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/107.jpg)
107
Figure 18: Illustration of linear measurements of skeletal relationship
![Page 108: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/108.jpg)
108
Figure 19: Illustration of linear measurements of dental relationship
![Page 109: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/109.jpg)
109
4.2 Assessment of Method Error
For any set of experiments, performing measurement is not enough. It
is essential to know if the measurement taken is good enough for achieving
the required aims (Barford, 1990).
Measurement errors may be systematic (errors associated with the
particular instrument or technique of measurement being used) or random
(errors produced by a large number of unpredictable and unknown
variations in the experimental situation).
There are different sources of the systematic error which may arise in
obtaining lateral skull radiographs if the geometry of the system varies and
no compensation is made. If measurements from two different studies are
compared; then it is assumed incorrectly that the magnifications are the
same, when two series of radiographs are measured by different persons
who have different concepts of a particular landmark (Houston, 1983).
Even when all systematic errors have either been eliminated or
corrected for, identical measurements were not obtained for repeated sets
of readings, the errors that remain were called random error (Young, 1962)
or experimental error.
![Page 110: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/110.jpg)
110
The random error arise as a result of variations in positioning of the
patient in the cephalostat. Variations in film density and sharpness also lead
to random error. The greatest source of the random errors is difficulty in
identifying a particular landmark or imprecision in its definition (Houston,
1983).
4.2.1 Assessment of cephalometric error.
For the accuracy of cephalometric measurements, the two main
sources of error; the systematic or bias, and random errors should be
controlled and/or assessed .
. 4.2.1.A Systematic error.
A radiograph, being a two dimensional representation of a three
dimensional object, is subject to distortion. And because the rays are not
parallel diverging from a small source onto the film is subjected to
enlargement.
The magnitude of enlargement depends on the relative distance
between the film, target and object. The closer the object to the x-ray
source and/or the further the film is from the object the greater the
enlargement (Bergersen, 1980).
![Page 111: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/111.jpg)
111
All radiographs utilized in this study were derived from a single
source with a fixed distance between the subject and the source of the x-
ray of 6 feet, and the same exposure being made by one machine.
The magnification factor was found to be 10.6% and calculated as
follows:
Actual measurement of ear rods = 8 mm
Radiographic measurements of the ear rods
a. If 9 mm closer to the film:
Measurement = 8.4 mm
Magnification - 0.4 x 100 - 5%
8
b. If 33.5 cm further away from the film:
Measurement = 9.3 mm
Magnification - 1.3 x 100 -16.2%
8
c. The midline magnification is
5 + 16.2 - 10.6%
2
The magnification factor 10.6% was entered into the computer to
compensate for enlargement of the linear measurements.
![Page 112: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/112.jpg)
112
4.2.1.B Random error.
This error was evaluated as follows:
1. Intra-examiner: A total of 30 radiographs were randomly selected,
retraced and redigitized after a period of 6 weeks.
2. Inter-examiner: The same 30 radiographs retraced and redigitized by
the supervisor as a reference examiner within the same week. The
error was assessed by the double determination method of (Dahlberg,
1940) and coefficient of reliability (Guilford and Fruchter, 1984).
![Page 113: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/113.jpg)
113
4.3 Assessing Skeletal Relationships
To differentiate between the different skeletal classes, I, II, and III, the
angle ANB (2.9° + 2.4°) of 11 years female as reported by Bhatia and
Leighton (1993) was utilized.
- Class I skeletal relationship = ANB > 0.5° < 5.3°
- Class II skeletal relationship = ANB > 5.3°
- Class III skeletal relationship = ANB < 0.5°
In this study, the class I skeletal relationship will be considered as
the control group.
![Page 114: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/114.jpg)
114
4.4 Assessing the skeleto-dental characteristic features of
Class II and III groups.
The characteristic features of class II and class III skeletal
relationships were assessed by comparing them to class I group which was
considered as a control group.
The above mentioned 18 angular, 17 linear and 2 proportion
measurements (see section 4.1.3.3 - 4.1.3.5) were used for comparison.
![Page 115: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/115.jpg)
115
4.5 Comparison of Saudi skeleto-dental characteristics to
established Cephalometric Standards
The values of skeleto-dental measurements obtained for class
I skeletal relationship (Control group) were compared to the
established cephalometric standards reported by Riolo et al. (1974)
for North Americans Caucasians, and Bhatia and Leighton (1993)
for British Caucasians. The previously mentioned 18 angular, 17
linear and 2 proportional parameters (see section 4.1.3.3 - 4.1.3.5)
were used for assessment and comparison between the different
skeletal classes.
![Page 116: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/116.jpg)
116
4.6 Statistical Analysis of the Data.
The following descriptive and inferential statistical procedure were
used for data analysis.
4.6.1 Descriptive Analysis.
The following statistics were calculated for each measurement.
1. Mean
Mean - ∑ X
N
where ∑ X = the summation of the measurement
N = The number of subjects in the sample
2. Standard Deviation of the measurement
S.D. - √
N-1
3. Standard error of the mean
S.E.- √
![Page 117: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/117.jpg)
117
4. Minimum
5. Maximum
4.6.2 Statistical Assessment of Method Error.
The method error was evaluated from the replicated
measurements (see section 4.2.1B).
4.6.2.1 Dalhberg's Method Error.
The most commonly used statistics in orthodontics to establish
random error of the method, strictly speaking reflect the errors of a
single measurement.
Dahlberg’s Formula - √
where d = difference between two readings
N = number of duplicants
This calculation was applied for both intra-examiner and inter-
examiner errors.
4.6.2.2 Coefficient of Reliability.
This statistic was computed to lend support to the various
description of the method error. A high correlation between the two
![Page 118: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/118.jpg)
118
readings would be an indication of the sensitiveness of the method, and
correspond to a low error.
Coeficient of Reliability - 1 -
Se2 = Variance due to Random Error
St2 = Total Variance of the Measurement
This calculation was done for both intra-examiner and inter-
examiner sets.
4.6.3 Statistical comparison between the groups.
The student t-test was used to evaluate the significant difference
between the mean values of the two samples used in this study as
follows:
4.6.3.1 Comparison between Saudi control group and Saudi class
II and class III groups.
The student t-test was applied for comparison between the
control group (class I) and class II and class III skeletal relationship
in the following way:
t-value - x1 – x2 (Guilford, Fruchter,1984)
S.E. of Difference
![Page 119: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/119.jpg)
119
S.E. of difference - S.D. of difference
√
S.E. of difference - √
N-1
Where X1 = mean of control group of Saudi sample
Where X2 = mean of class 11 or class III skeletal
relationship of Saudi sample
S.E. difference = the standard error of the difference between the
two means
d = difference between the two means
4.6.3.2 Comparison of control group of Saudi sample to
established cephalometric standards.
The t-test is applied to compare the control Saudi group with
Caucasian norms, Riolo et al. (1974) and Bhatia and Leighton (1993) in the
following way:
t-value -
√ (Swinscow. 1983, pp, 35)
S.D. - √
N – 1
![Page 120: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/120.jpg)
120
Degree of freedom N-l
Where M = mean of established standards of Caucasian
population
X = mean of the Saudi sample
SD = standard deviation of the Saudi sample
N = number of the Saudi sample
4.6.3.3 The level of significance used for comparing the samples.
To identify the real difference between the means of the two
samples, the different levels of significance as described by Rowntree
(1991), were used.
1. P 0.05 (*). The significant level at 5 % i.e. five chances in l00,
and it is often called "significant".
2. P 0.01 (**). The significant level at 1 % i.e. one chance in
100, and it is often called "highly significant".
3. P 0.001 (***). The significant level at 0.1 % l.e. one
chance in 1000 and it is often called "very highly significant".
4. P = is accepted as being statistically significant at these three
levels.
![Page 121: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/121.jpg)
121
5.0 RESULTS
![Page 122: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/122.jpg)
122
5.0 Results
The results of this study will be presented in the following way.
5.1 The method error and reliability were covered in Tables from 5.1.1 to
5.1.3.
5.2 The classification of skeletal relation of the Saudi sample into
various classes and their distribution were presented in Table 5.2.1 and
Figure (19). From the above class I was considered as control group.
5.3 The results of comparing the skeleton-dental characteristics of class II
and class III skeletal relationships to class I group were presented in Tables
from 5.3.1.a.1 to 5.3.5.c.1.
5.4 The results of comparing skeleto-dental characteristics of Saudi
female class I skeletal relationship (control group) to established
cephalometric mean value of North American whites, (Riolo et al., 1974)
and British caucasian, (Bhatia and Leighton, 1993) were presented in
Tables from 5.4.l.a.1 to 5.4.5.c.l.
![Page 123: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/123.jpg)
123
5.1 The method error and reliability of cephalometric
landmarks.
The method error was expressed by Dahlberg’s double determination
value and coefficient of reliability for 37 variables observed in repeated
recording of 30 radiographs. The results were presented in Table 5.1.1 for
angular measurements, Table 5.1.2 for the linear measurements and Table
5.1.3 for the proportional measurements.
It can be seen from the tables that the range of intra-examiner error
was from 0.4170 to 1.468
0 for angular measurements, from 0.404 mm to
0.711mm for linear measurements and from 0.447% to 0.531 % for
proportional measurements. The range of inter-examiner error was from
0.6980 to 2.912
0 for angular measurements, from 0.662 mm to 1.144 mm,
for linear measurements and from 0.768% to 0.877% as proportional
measurements.
The largest error was 1.468° and 1.432° for the variables FH/occ
and SN/occ respectively which could be due to the landmark identification.
Difficulty was encountered in the accurate location of the landmarks
involved in oc point, since the radiographs were of growing children and
the premolar had not fully erupted. As a result, a slight shift in the position
of this point will magnify the error involved. This is supported by the large
error of the inter-examiner 2.912° and 2.869°
![Page 124: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/124.jpg)
124
respectively. It can also be seen that the intra-examiner error was high
for (inter incisal angle) 1.009°. And for (LIA-LIE/MP2) 0.989° and this
was supported by the large error of the inter-examiner 1.469° and 1.432°
respectively.
The coefficient of reliability for the measurement of SN/occ and
PH/occ was less than 0.9. This may indicate that this measurement
should be treated with suspicion (Houston, 1983).
![Page 125: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/125.jpg)
125
5.1 The method error and reliability of cephalometric landmarks.
Table 5.1.1 The method error and coefficient of reliability of the intra examiner and
inter examiner for angular measurements of 18 variables in the skeleto dental
relationship of 30 repeated recordings. All readings in degrees.
Variables Intra Examiner Inter Examiner
Angular
Measurements
Dahlberg's
Method
Error
Coefficient
of
Reliability
Dahlberg's
Method
Error
Coefficient
of
Reliability
1. SNA 0.513 0.963 1.122 0.899
2. SNB 0.465 0.966 0.978 0.912
3. ANB 0.417 0.965 0.724 0.932
4. Angle of convexity 0.549 0.966 1.005 0.905
5. Facial angle 0.481 0.961 0.727 0.936
6. A-B plane angle 0.523 0.959 0.826 0.926
7. Saddle angle 0.554 0.965 1.136 0.902
8. Gonial angle 0.726 0.932 1.232 0.901
9. SN/Occ 1.432 0.895 2.869 0.546
10. SN/MP1 0.522 0.965 0.967 0.930
11. FH/Occ 1.468 0.894 2.912 0.513
12. FH/MP2 0.557 0.961 0.808 0.936
13. V-axis angle 0.476 0.962 0.698 0.939
14. Facial axia angle 0.443 0.967 0.752 0.940
15. LlA-LlE/MP2 0.989 0.922 1.432 0.896
16. UIA-UIE/NA 0.846 0.914 1.157 0.893
17. LlE-LlA/NB 0.795 0.937 1.472 0.885
18. Interincisal angle 1.009 0.909 1.469 0.896
![Page 126: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/126.jpg)
126
5.1 The method error ••• (continued)
Table 5.1.2 The method error and coefficient of reliability of the intra examiner and
inter examiner for the linear measurements of 17 variables in the skeleto dental
relationship of 30
Variables Intra Examiner Inter Examiner
Linear
Measurements
Dahlberg's
Method
Error
Coefficient
of
Reliability
Dahlberg's
Method
Error
Coefficient
of
Reliability
1. A / N ┴ FH 0.519 0.963 1.144 0.892
2. Pog / N ┴ FH 0.588 0.966 1.484 0.885
3. Co - A 0.435 0.966 0.688 0.943
4. Co - Gn 0.451 0.967 0.945 0.917
5. Go - Me 0.662 0.953 1.121 0.892
6. N-S 0.476 0.965 0.830 0.929
7. S - Ar 0.494 0.965 0.878 0.932
8. Ar - Go 0.711 0.959 0.844 0.936
9. S - Go 0.562 0.964 0.816 0.941
10. N - Me 0.478 0.967 0.899 0.936
11. ANS - Me 0.454 0.966 0.856 0.931
12. UIE / NA 0.471 0.959 0.771 0.928
13. LIE / NB 0.404 0.966 0.669 0.939
14. UIE / A Pog 0.449 0.961 0.729 0.931
15. UIE / A ┴ FH 0.501 0.959 0.771 0.928
16. LIE/A Pog 0.422 0.963 0.662 0.938
17. Pog / NB 0.458 0.952 0.775 0.931
![Page 127: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/127.jpg)
127
5.1 The method error… (continued)
Table 5.1.3 The method error and coefficient of reliability of the intra examiner and
inter examiner for proportional measurements of 2 variables in the skeleto dental
relationship of 30 repeated recordings. All readings in %.
Variables Intra Examiner Inter Examiner
Proportions
Dahlberg's
Method
Error
Coefficient
of
Reliability
Dahlberg's
Method
Error
Coefficient
of
Reliability
1. ANS – Me / N - Me 0.447 0.956 0.768 0.910
2. S – Go / N – Me 0.531 0.963 0.877 0.931
![Page 128: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/128.jpg)
128
5.2 The skeletal classification of the 205 Saudi females based on
ANB angle, and their distribution
The frequency and percentage of skeletal classification of the saudi
females were presented in tabular form in Table 5.2.1, and graphically as
pie chart in Fig. 20. It is clear from the results that skeletal class I
constitutes the highest percentage (68.3 %), whereas, class II and class III
exhibited relatively similar percentage of 16.1 % and 15.6%, respectively.
Angle ANB of values 2.90+2.4
0 as reported by Bhatia and Leighton
(1993) was used to represent class I, any reading above that was considered
class II skeletal relationship and any reading below that was considered
class III skeletal relationship.
![Page 129: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/129.jpg)
129
5.2 The skeletal classification of the 205 Saudi females based on ANB
angle and their distribution
Table 5.2.1 The frequency and percentage of the skeletal discrepancy of
205 Saudi females classified by the ANB angle based on the comparison to
ANB value of British white caucasian.
Figure 20 Pie chart of the frequency and percentage of the skeletal
discrepancy of 205 Saudi female classified by the ANB angle based on the
comparison to ANB value of British white caucasian.
Skeletal relationship
Frequency
Percent
Class I 140 68.3%
Class II 33 16.1%
Class III 32 15.6%
![Page 130: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/130.jpg)
130
5.3 The skeleto dental characteristics of skeletal class II and class III
compared to class I skeletal relationship of Saudi females.
This part was divided into five sections:
5.3.1 Skeletal relationship
The results of the analysis of skeletal relationship were presented in
Tables from 5.3.1.a.l to 5.3.1.a.3 (antero-posterior dimension), and Tables
5.3.1.b.l to 5.3.1.b.13 (vertical relationship). It is clear from the tables that
there were significant differences between class II and class I skeletal
relationship, and also between class III and class I skeletal relationship in
anteroposterior dimension. For vertical relationship, there were no
significant difference for most of the comparison except for SN/MP1
SN/occ (class III), Y-axis angle and facial axis angle for both class II and
class III and ramus height in class II only.
5.3.2 Cranial base.
The results of the cranial base measurements were covered in Tables
5.3.2.1 to 5.3.2.3. It is clear that there were no significant differences
between all classes in both angular and linear measurements of the cranial
base.
![Page 131: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/131.jpg)
131
5.3.3 Maxilla
The results of maxillary measurements were presented in Tables
5.3.3.1 to 5.3.3.3. These results showed that there were significant
differences between the skeletal class I, class II, and class III in both
angular and linear measurements. The level of significance in class II
compared to class I skeletal relationship was very high.
5.3.4 Mandible
The results of the mandibular measurements were presented in
Tables 5.3.4.1 to 5.3.4.6. It is obvious from the tables that there was
significant differences between skeletal class I and class II skeletal
relationship. Skeletal class III was compared to skeletal class I showed
no significant differences. Except one measurement (pog/N ┴ FH in
mm) showed a significant difference.
5.3.5 Dento alveolar relationship
The results of dento-alveolar relationship measurements were
presented in Tables 5.3.5.a.l to 5.3.5.a.4 (maxillary incisor position),
5.3.5.b.l to 5.3.5.b.4 (mandibular incisor position), and Tables 5.3.5.c.1
(maxillary mandibular inter-incisal angle). The maxillary incisor position,
![Page 132: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/132.jpg)
132
or skeletal class II angulation were statistically significant when compared
to skeletal class I and class III. Mandibular incisor position and angulation
also showed significant differences between the three skeletal classes
except for LIE/A Pog (mm) when skeletal class II was compared to skeletal
class I. Inter-incisal angle, (Table 5.3.5.c.l) showed a statistical significant
difference when skeletal class II was compared to skeletal class I.
However, no statistical significant difference was observed between
skeletal class III and skeletal class I.
![Page 133: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/133.jpg)
133
5.3 The skeleto dental characteristics of class II and class III
skeletal compared to class I skeletal relationship of Saudi
females.
5.3.1 The skeletal relationship
5.3.1.a Anteroposterior relationship
Table 5.3.1.a.l The mean and spread of measuring the ANB angle in
degrees recorded for class I, class II, class III skeletal relationship of
Saudi females. The t-value of the mean difference of (class I-class II) and
(class I-class III) is shown with its level of significance.
ANB dg Mean S.D. Min. Max. S.E.
Class I Group
(N = 140) 3.1 1.1 0.8 5.3 0.09
Class II Group
(N = 33) 7.0 1.5 5.5 11.1 0.27
Class III
Group
(N = 32)
-0.5 0.9 -2.9 0.4 0.16
t-value (Class I - Class II) = 13.2
Level of significance - ***
t-value (Class I - Class II =16.8
Level of significance - ***
P ≤ 0.05 (*) significant
P ≤ 0.01 (**) highly significant
P ≤ 0.01 (***) very highly significant
N
S
= not significant
![Page 134: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/134.jpg)
134
5.3 The skeleto dental characteristics… (continued)
5.3.1 The skeletal relationship… (continued)
5.3.1.a Anteroposterior relationship…(continued)
Table 5.3.1.a.2 The mean and spread of measuring A-B plane angle in
degrees recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance.
A - B Plane
Angle dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) -4.8 1.8 -0.5 -10.0 0.15
Class II Group
(N = 33) -9.8 2.5 -5.5 -7.5 0.45
Class III Group
(N = 23) 0.05 1.3 -3.9 2.7 0.2
t-value (Class I - Class II) = 10.3
Level of significance - ***
t-value (Class I - Class III =13.9
Level of significance - ***
Table 5.3.1.a.3 The mean and spread of measuring the angle of convexity
in degrees recorded for class I, class II, class III skeletal relationship of
Saudi females. The t- value of the mean difference of (class I - class II) and
(class I - class Ill) is shown with its level of significance.
Angle of
Convexity dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 5.4 3.1 0.1 13.9 0.27
Class II Group
(N = 33) 14.5 3.6 8.6 24.5 0.62
Class III Group
(N = 32) -2.8 2.6 -8.5 3.20 0.39
t-value (Class I - Class II) = 14.2
Level of significance - ***
t-value (Class I - Class III = 17.2
Level of significance - ***
![Page 135: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/135.jpg)
135
5.3 The skeleto dental characteristics… (continued)
5.3.1 The skeletal relationship… (continued)
5.3.1.b Vertical relationship
Table 5.3.1.b.l The mean and spread of measuring the SN/MP1 angle in
degrees recorded for class I, class II, class III skeletal relationship of
Saudi females. The t- value of the mean difference of (class I -class II)
and (class I - class Ill) is shown with its level of significance.
Table 5.3.1.b.2 The mean and spread of measuring the SN/occ angle in
degrees recorded for class I, class II, class III skeletal relationship of
Saudi females. The t- value of the mean difference of (class I - class II)
and (class I - class III) is shown with its level of significance.
SN/MP1 dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 35.8 5.1 23.7 51.4 0.43
Class II Group
(N = 33) 37.5 5.8 26.8 51.2 1.02
Class III Group
(N = 32) 33.6 5.1 18.3 42.7 0.91
t-value (Class I - Class II) = 1.6
Level of significance - NS
t-value (Class I - Class III = 2.2
Level of significance - *
SN/Occ dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 21.7 5.4 8.0 42.0 0.45
Class II Group
(N = 33) 21.7 5.4 8.0 42.0 0.45
Class III Group
(N = 32) 19.2 6.2 5.9 35.2 1.1
t-value (Class I - Class II) = 0.8
Level of significance - NS
t-value (Class I - Class III = 2.3
Level of significance - *
![Page 136: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/136.jpg)
136
5.3 The skeleto dental characteristics… (continued)
5.3.1 The skeletal relationship … (continued)
5.3.1.b Vertical relationship… (continued)
Table 5.3.1.b.3 The mean and spread of measuring Y-axis angle in degrees
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t-value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance.
Table 5.3.1.b.4 The mean and spread of measuring the FH/occ angle in
degrees recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance.
FH/MP2 dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 27.7 4.8 15.1 39.5 0.41
Class II Group
(N = 33) 29.5 5.9 20.3 40.6 1.02
Class III Group
(N = 32) 26.3 4.8 15.8 35.2 0.86
t-value (Class I - Class II) = 1.7
Level of significance - NS
t-value (Class I - Class III = 1.5
Level of significance - NS
FH/Occ dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 13.5 4.9 4.1 29.9 0.41
Class II Group
(N = 33) 13.6 5.4 3.7 23.2 0.94
Class III Group
(N = 32) 11.9 6.3 1.7 26.8 1.1
t-value (Class I - Class II) = 0.10
Level of significance - NS
t-value (Class I - Class III = 1.3
Level of significance - NS
![Page 137: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/137.jpg)
137
5.3 The skeleto dental characteristics… (continued)
5.3.1 The skeletal relationship… (continued)
5.3.1.b Vertical relationship… (continued)
Table 5.3.1.b.5 The mean and spread of measuring Y-axis angle in degrees
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t-value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance.
Table 5.3.1.b.6 The mean and spread of measuring facial axis angle in
degrees recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance.
Y Axis Angle
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 60.0 3.1 50.2 66.6 0.26
Class II Group
(N = 33) 61.4 3.8 54.1 69.8 0.67
Class III Group
(N = 32) 58.5 3.6 51.6 66.0 0.63
t-value (Class I - Class II) = 2.3
Level of significance - *
t-value (Class I - Class III = 2.2
Level of significance - *
Facial axis
angle dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 92.4 4.0 73 100.5 0.3
Class II Group
(N = 33) 94.5 2.4 88.3 100 0.4
Class III Group
(N = 32) 89.5 3.3 83.1 96.2 0.5
t-value (Class I - Class II) = 3.5
Level of significance - ***
t-value (Class I - Class III = 3.8
Level of significance - ***
![Page 138: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/138.jpg)
138
5.3 The skeleton dental characteristics… (continued)
5.3.1 The skeletal relationship ... (continued)
5.3.1.b Vertical relationship ... (continued)
Table 5.3.1.b.7 The mean and spread of measuring gonial angle in degrees
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t-value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance.
Gonial Angle
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 126.8 6.4 110.9 143.2 0.54
Class II Group
(N = 33) 127.5 8.3 109.1 142.2 1.4
Class III Group
(N = 32) 127.9 6.7 113.4 142.9 1.2
t-value (Class I - Class II) = 0.45
Level of significance - NS
t-value (Class I - Class III = 0.81
Level of significance - NS
![Page 139: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/139.jpg)
139
5.3 The skeleto dental characteristics… (continued)
5.3.1 The skeletal relationship… (continued)
5.3.1.b Vertical relationship… (continued)
Table 5.3.1.b.8 The mean and spread of measuring lower facial height in
mm recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I – class II) and (class
I - class III) is shown with its level of significance.
Table 5.3.1.b.9 The mean and spread of measuring anterior facial height in
mm recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance.
ANS - Me mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 57.2 4.3 47.2 66.9 0.36
Class II Group
(N = 33) 57.6 4.2 48.9 66.7 0.74
Class III Group
(N = 32) 56.4 4.4 49.1 68.5 0.78
t-value (Class I - Class II) = 0.5
Level of significance - NS
t-value (Class I - Class III = 0.08
Level of significance - NS
N - Me mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 103.7 5.6 88.0 115.2 0.47
Class II Group
(N = 33) 103.5 6.4 92.3 117.5 1.1
Class III Group
(N = 32) lO1.8 5.5 93.8 119.4 0.98
t-value (Class I - Class II) = 0.14
Level of significance - NS
t-value (Class I - Class III = 1.7
Level of significance - NS
![Page 140: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/140.jpg)
140
5.3 The skeleto dental characteristics … (continued)
5.3.1 The skeletal relationship… (continued)
5.3.1.b Vertical relationship.. (Continued)
Table 5.3.1.b.10 The mean and spread of measuring posterior facial height
in mm recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance.
Table 5.3.1.b.11 The mean and spread of measuring ramus height in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t-value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance.
S- Go mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 65.6 5.0 49.6 79.6 0.42
Class II Group
(N = 33) 64.1 4.7 54.8 76.5 0.83
Class III Group
(N = 32) 65.6 5.1 57.0 82.6 0.91
t-value (Class I - Class II) = 1.5
Level of significance - NS
t-value (Class I - Class III = 0.4
Level of significance - NS
Ramus Height
mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 38.9 3.6 29.4 49.0 0.30
Class II Group
(N = 33) 37.4 4.0 30.0 49.08 0.70
Class III Group
(N = 32) 39.7 4.3 31.3 49.8 0.76
t-value (Class I - Class II) = 2.0
Level of significance - *
t-value (Class I - Class III = 1.1
Level of significance - NS
![Page 141: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/141.jpg)
141
5.3 The skeleto dental characteristics … (continued)
5.3.1 The skeletal relationship… (continued)
5.3.1.b Vertical relationship.. (Continued)
Table 5.3.1.b.12 The mean and spread of measuring ANS-Me/N-ME in
percentage recorded for class I, class II, class III skeletal relationship of
Saudi females. The t- value of the mean difference of (class I - class II) and
(class I - class III) is shown with its level of significance
Table 5.3.1.b.13 The mean and spread of measuring S-Go/N-Me in
percentage recorded for class I, class II, class III skeletal relationship of
Saudi females. The t- value of the mean difference of (class I - class II) and
(class I - class III) is shown with its level of significance
ANS-Me/N-
ME
%
Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 55.1 2.3 49.6 63.1 0.19
Class II Group
(N = 33) 55.6 2.1 51.6 60.6 0.37
Class III Group
(N = 32) 55.4 2.2 50.8 61.1 0.45
t-value (Class I - Class II) = 1.1
Level of significance – NS
t-value (Class I - Class III = 0.6
Level of significance - NS
S-Go/N-Me % Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 63.3 4.2 53.5 73.9 0.35
Class II Group
(N = 33) 62.0 4.7 51.9 71.4 0.83
Class III Group
(N = 32) 64.5 4.5 57.5 77.4 0.8
t-value (Class I - Class II) = 1.5
Level of significance – NS
t-value (Class I - Class III = 1.4
Level of significance - NS
![Page 142: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/142.jpg)
142
5.3 The skeleto dental characteristics … (continued)
5.3.2 The cranial base
Table 5.3.2.1 The mean and spread of measuring S-N in mm recorded for
class I, class II, class III skeletal relationship of Saudi females. The t- value
of the mean difference of (class I - class II) and (class I - class III) is shown
with its level of significance
Table 5.3.2.2 The mean and spread of measuring S-Ar in mm recorded for
class I, class II, class III skeletal relationship of Saudi females. The t- value
of the mean difference of (class I - class II) and (class I - class III) is shown
with its level of significance
SS-N mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 64.3 2.7 57.5 72.8 0.23
Class II Group
(N = 33) 64.2 2.4 55.6 69.7 0.47
Class III Group
(N = 32) 64.9 3.3 59.2 73.3 0.59
t-value (Class I - Class II) = 0.2
Level of significance – NS
t-value (Class I - Class III = 1.0
Level of significance - NS
S-Ar mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 29.8 2.9 23.3 39.4 0.24
Class II Group
(N = 33) 29.5 1.8 24.1 34.6 0.32
Class III Group
(N = 32) 29.8 2.6 25.4 36.5 0.50
t-value (Class I - Class II) = 0.8
Level of significance – NS
t-value (Class I - Class III = 0.06
Level of significance - NS
![Page 143: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/143.jpg)
143
5.3 The skeleto dental characteristics … (continued)
5.3.2 The cranial base … (continued)
Table 5.3.2.3 The mean and spread of saddle angle in degrees recorded for
class I, class II, class III skeletal relationship of Saudi females. The t- value
of the mean difference of (class I - class II) and (class I - class III) is shown
with its level of significance
Saddle Angle
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 123.5 5.3 105.2 139.1 0.45
Class II Group
(N = 33) 123.9 3.6 114.7 131.2 0.63
Class III Group
(N = 32) 123.3 3.3 113.2 132.4 0.58
t-value (Class I - Class II) = 0.38
Level of significance – NS
t-value (Class I - Class III = 0.198
Level of significance - NS
![Page 144: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/144.jpg)
144
5.3 The skeleto dental characteristics … (continued)
5.3.3 The Maxilla
Table 5.3.3.1 The mean and spread of measuring SNA angle in degrees
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Table 5.3.3.2 The mean and spread of measuring A/N ┴ FH in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
SNA dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 80.8 3.7 71.3 92.3 0.31
Class II Group
(N = 33) 83.3 2.5 78.2 87.0 0.43
Class III Group
(N = 32) 78.6 4.2 70.1 91.8 0.75
t-value (Class I - Class II) = 3.6
Level of significance – ***
t-value (Class I - Class III = 2.9
Level of significance - **
A/N ┴ FH mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) -1.9 3.2 -10.9 7.5 0.27
Class II Group
(N = 33) 0.3 2.4 4.7 3.8 0.41
Class III Group
(N = 32) -3.9 3.6 -11.8 6.4 0.64
t-value (Class I - Class II) = 4.5
Level of significance – ***
t-value (Class I - Class III = 3.0
Level of significance - **
![Page 145: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/145.jpg)
145
5.3 The skeleto dental characteristics … (continued)
5.3.3 The Maxilla … (continued)
Table 5.3.3.3 The mean and spread of measuring maxillary length in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Maxillary
Length mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 74.9 4.4 50.4 85.5 0.38
Class II Group
(N = 33) 76.6 2.9 70.8 83.9 0.51
Class III Group
(N = 32) 72.4 5.4 50.0 81.6 0.97
t-value (Class I - Class II) = 2.6
Level of significance – **
t-value (Class I - Class III = 2.7
Level of significance - **
![Page 146: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/146.jpg)
146
5.3 The skeleto dental characteristics … (continued)
5.3.4 The Mandible
Table 5.3.4.1 The mean and spread of measuring SNB angle recorded for
class I, class II, class III skeletal relationship of Saudi females. The t- value
of the mean difference of (class I - class II) and (class I - class III) is shown
with its level of significance
Table 5.3.4.2 The mean and spread of measuring facial angle in degrees
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
SNB dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 77.7 3.5 70.2 89.3 0.30
Class II Group
(N = 33) 76.3 2.4 72.0 80.5 0.42
Class III Group
(N = 32) 79.2 4.2 70.3 92.7 0.75
t-value (Class I - Class II) = 2.6
Level of significance – **
t-value (Class I - Class III = 2.0
Level of significance - *
Facial Angle
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 86.4 3.2 79.4 95.6 0.27
Class II Group
(N = 33) 84.5 3.2 77.9 93.0 0.56
Class III Group
(N = 32) 87.4 3.9 77.9 95.5 0.69
t-value (Class I - Class II) = 3.0
Level of significance – **
t-value (Class I - Class III = 0.6
Level of significance - NS
![Page 147: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/147.jpg)
147
5.3 The skeleto dental characteristics … (continued)
5.3.4 The Mandible … (continued)
Table 5.3.4.3 The mean and spread of measuring pog ┴ FH in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Table 5.3.4.4 The mean and spread of measuring pog/NB in mm recorded
for class I, class II, class III skeletal relationship of Saudi females. The t-
value of the mean difference of (class I - class II) and (class I - class III) is
shown with its level of significance
pog ┴ FH mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) -8.1 6.1 -22.9 12.5 0.51
Class II Group
(N = 33) -11.2 4.7 -18.8 -3.3 0.82
Class III Group
(N = 32) -5.2 6.9 -19.3 15.4 1.20
t-value (Class I - Class II) = 2.7
Level of significance – **
t-value (Class I - Class III = 2.3
Level of significance - **
Pog/NB Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 0.8 1.2 -2.3 4.8 0.10
Class II Group
(N = 33) 0.1 1.0 -2.1 2.8 0.17
Class III Group
(N = 32) 1.3 1.1 0.7 4.1 0.20
t-value (Class I - Class II) = 2.8
Level of significance – **
t-value (Class I - Class III = 1.8
Level of significance - NS
![Page 148: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/148.jpg)
148
5.3 The skeleto dental characteristics … (continued)
5.3.4 The Mandible … (continued)
Table 5.3.4.5 The mean and spread of measuring mandibular body length
in mm recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance
Table 5.3.4.6 The mean and spread of measuring mandibular length in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
mandibular
body length
mm
Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 60.3 4.1 47.6 70.6 0.35
Class II Group
(N = 33) 59.2 3.2 54.1 65.3 0.56
Class III Group
(N = 32) 61.5 3.6 53.7 68.0 0.63
t-value (Class I - Class II) = 1.4
Level of significance – NS
t-value (Class I - Class III = 0.3
Level of significance - NS
mandibular
length mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 94.4 5.1 80.8 109.6 0.43
Class II Group
(N = 33) 91.9 4.9 83.6 102.8 0.86
Class III Group
(N = 32) 95.1 5.1 83.0 106.2 0.91
t-value (Class I - Class II) = 2.4
Level of significance – **
t-value (Class I - Class III = 0.6
Level of significance - NS
![Page 149: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/149.jpg)
149
5.3 The skeleto dental characteristics … (continued)
5.3.4 The dento alveolar relationship
5.3.5.a Maxillary incisor position
Table 5.3.5.a.1 The mean and spread of measuring UIE/NA in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Table 5.3.5.a.2 The mean and spread of measuring UIE/A ┴ FH in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
UIE/NA
mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 5.9 2.2 -3.0 11.9 0.1
Class II Group
(N = 33) 4.0 2.6 -1.8 10.2 0.4
Class III Group
(N = 32) 8.5 2.2 3.6 12.4 0.3
t-value (Class I - Class II) = 4.2
Level of significance – **
t-value (Class I - Class III = 4.8
Level of significance - ***
UIE/A ┴ FH
mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 4.3 2.3 -5.5 12.0 0.19
Class II Group
(N = 33) 3.2 2.4 -2.0 9.2 0.41
Class III Group
(N = 32) 5.6 2.4 0.08 11.3 0.43
t-value (Class I - Class II) = 2.2
Level of significance – *
t-value (Class I - Class III = 2.9
Level of significance - **
![Page 150: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/150.jpg)
150
5.3 The skeleto dental characteristics … (continued)
5.3.4 The dento alveolar relationship … (continued)
5.3.5.a Maxillary incisor position … (continued)
Table 5.3.5.a.3 The mean and spread of measuring UIE/A pog in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Table 5.3.5.a.4 The mean and spread of measuring UIA-UIE/NA in
degrees recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance
UIE/A Pog
mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 6.9 2.3 -3.2 13.1 0.19
Class II Group
(N = 33) 8.1 2.5 3.5 13.8 0.44
Class III Group
(N = 32) 6.2 2.2 0.9 10.4 0.4
t-value (Class I - Class II) = 2.4
Level of significance – **
t-value (Class I - Class III = 1.6
Level of significance - NS
UIA-UIE/NA
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 25.6 5.8 2.6 40.6 0.49
Class II Group
(N = 33) 22.3 6.8 9.2 36.8 1.1
Class III Group
(N = 32) 32.0 5.0 20.6 43.6 0.89
t-value (Class I - Class II) = 2.8
Level of significance – **
t-value (Class I - Class III = 5.6
Level of significance - ***
![Page 151: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/151.jpg)
151
5.3 The skeleto dental characteristics … (continued)
5.3.4 The dento alveolar relationship … (continued)
5.3.5.a Mandibular incisor position
Table 5.3.5.b.1 The mean and spread of measuring LIE/NB in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Table 5.3.5.b.2 The mean and spread of measuring LIE/Apog in mm
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
LIE/NB
mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 6.6 2.0 -0.8 12.0 0.17
Class II Group
(N = 33) 8.4 2.2 4.2 14.3 0.38
Class III Group
(N = 32) 5.1 2.1 1.6 9.1 0.37
t-value (Class I - Class II) = 4.3
Level of significance – ***
t-value (Class I - Class III = 3.5
Level of significance - ***
LIE/Apog mm Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 3.6 2.2 - 5.8 10.5 0.19
Class II Group
(N = 33) 3.4 2.4 -0.6 9.2 0.42
Class III Group
(N = 32) 4.0 2.4 0.08 9.2 0.43
t-value (Class I - Class II) = 0.3
Level of significance – NS
t-value (Class I - Class III = 0.9
Level of significance - NS
![Page 152: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/152.jpg)
152
5.3 The skeleto dental characteristics … (continued)
5.3.4 The dento alveolar relationship … (continued)
5.3.5.a Mandibular incisor position … (continued)
Table 5.3.5.b.3 The mean and spread of measuring LIE-LIA/NB in degrees
recorded for class I, class II, class III skeletal relationship of Saudi females.
The t- value of the mean difference of (class I - class II) and (class I - class
III) is shown with its level of significance
Table 5.3.5.b.4 The mean and spread of measuring LIA-LIE/MP2 in
degrees recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance
LIE-LIA/NB
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 30.4 5.5 10.0 43.5 0.47
Class II Group
(N = 33) 33.4 5.0 25.9 43.4 0.87
Class III Group
(N = 32) 26.0 5.2 17.4 39.1 0.93
t-value (Class I - Class II) = 2.7
Level of significance – **
t-value (Class I - Class III = 3.6
Level of significance - ***
LIA-LIE/MP2
dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 97.0 5.9 -10.1 20.5 0.5
Class II Group
(N = 33) 99.5 5.8 -0.4 21.2 1.0
Class III Group
(N = 32) 93.8 6.2 -9.0 18.2 1.1
t-value (Class I - Class II) = 2.20
Level of significance – *
t-value (Class I - Class III = 2.7
Level of significance - **
![Page 153: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/153.jpg)
153
5.3 The skeleto dental characteristics … (continued)
5.3.5 The dento alveolar relationship … (continued)
5.3.5.c The maxillary-mandibular incisor relation … (continued)
Table 5.3.5.c.1 The mean and spread of measuring interincisal angle in
degrees recorded for class I, class II, class III skeletal relationship of Saudi
females. The t- value of the mean difference of (class I - class II) and (class
I - class III) is shown with its level of significance
Interincisal
Angle dg Mean S.D Min. Max. S.E.
Class I Group
(N = 140) 120.6 9.1 97.7 163.5 0.77
Class II Group
(N = 33) 117.2 9.6 96.6 137.2 1.6
Class III Group
(N = 32) 121.9 7.8 102.7 135.0 1.3
t-value (Class I - Class II) = 1.9
Level of significance – *
t-value (Class I - Class III = 0.7
Level of significance - NS
![Page 154: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/154.jpg)
154
5.4 Comparison of the skeleto-dental characteristics of Saudi females
class I skeletal relationship (control group) to established mean
value of North American whites, (Riolo et al., 1974) and British
caucasian, (Bhatia and Leighton, 1993). The results of the comparison was also divided into 5 sections:
5.4.1 Skeletal relationship.
The results of skeletal relationship were presented for the antero
posterior dimension in Tables 5.4.l.a.1 to 5.4.l.a.3 and for the vertical
relationship in Tables 5.4.l.b.1 to 5.4.l.b.12.
It can be seen that the differences between the mean value of Saudi
control group compared to the established caucasian values showed
different level of significance in the anteroposterior dimension. When the
vertical dimensions of the Saudi and the British samples were compared,
the level of significance was found to be less.
5.4.2 Cranial base. The results of cranial base were presented in Tables 5.4.2.1 to
5.4.2.3. The results obtained showed no significant difference between the
Saudi and the British samples, on the other hand, all other comparisons
were significant.
![Page 155: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/155.jpg)
155
5.4.3 Maxilla
The results of the maxillary measurements were presented in Tables
5.4.3.1 to 5.4.3.3. These results showed that the only insignificant
difference found between the Saudi and North American sample was in
SNA angle. The other values were significant.
5.4.4. Mandible.
The results of the mandibular measurements were presented in
Tables 5.4.4.1. to 5.4.4.6. The results revealed that the only insignificant
difference observed between the Saudi and North American sample was
in SNB angle. The other values showed differences.
5.4.5 Dento-alveolar relationship.
The results of measurements of the dento-alveolar relationship were
presented in Tables 5.4.5.a.1 to 5.4.5.a.4 (maxillary incisor position),
Tables 5.4.5.b.1 to 5.4.5.b.4 (mandibular incisor position), and Table
5.4.5.c.1 (maxillary-mandibular incisor position). It was noticed that, both
maxillary and mandibular incisor position (angular and linear
measurements) showed some degree of bimaxillary proclination when the
Saudi sample was compared to the British and the North American
samples.
![Page 156: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/156.jpg)
156
5.4 Comparison of skeleto dental characteristics of Saudi females class
I skeletal; relationship (control group) to established mean value of
North American Caucasian and British Caucasian.
5.4.1 The skeletal relationship
5.4.1.a. The antero posterior skeletal relationship
Table 5.4.1.a.1 The mean and spread of measuring ANB in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
NAC = North Americans Caucasians Norms
BC = British Caucasian Norms
NR = Not recorded
P 0.05 (
*) significant
P P 0.001 (***) very highly significant
NS = not significant
ANB dg Mean S.D
Saudi Class 3.1 1.1
N.A.C 3.8 2.2
B.C 2.9 2.4
t-value1 (Saudi-NAC) = 7.7
Level of significance – ***
t-value2 (Saudi-BC) = 2.2
Level of significance – *
![Page 157: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/157.jpg)
157
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.a. The antero posterior skeletal relationship … (continued)
Table 5.4.1.a.2 The mean and spread of measuring AB plane angle in
degrees recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
Table 5.4.1.a.3 The mean and spread of measuring angle of convexity in
degrees recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
AB Plane Angle
dg Mean S.D
Saudi Class - 4.8 1.8
N.A.C -5.9 3.2
B.C -5.4 3.4
t-value1 (Saudi-NAC) = 7.33
Level of significance – ***
t-value2 (Saudi-BC) = 4.0
Level of significance – ***
Angle of Convexity
dg Mean S.D
Saudi Class 5.4 3.2
N.A.C 6.6 4.5
B.C 5.4 6.1
t-value1 (Saudi-NAC) = 4.44
Level of significance – ***
t-value2 (Saudi-BC) = 0
Level of significance – NS
![Page 158: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/158.jpg)
158
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b The vertical relationship
Table 5.4.1.b.1 The mean and spread of measuring SN/MP in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.1.b.2 The mean and spread of measuring SN/occ in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
SN/MP1 dg Mean S.D
Saudi Class 35.8 5.1
N.A.C 34.6 5.3
B.C NR NR
t-value1 (Saudi-NAC) = 2.79
Level of significance – **
SN/Occ
dg Mean S.D
Saudi Class 21.7 5.4
N.A.C 17.9 4.5
B.C 20.5 4.4
t-value1 (Saudi-NAC) = 8.44
Level of significance – ***
t-value2 (Saudi-BC) = 2.66
Level of significance – **
![Page 159: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/159.jpg)
159
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b The vertical relationship … (continued)
Table 5.4.1.b.3 The mean and spread of measuring FH/MP2 in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.1.b.4 The mean and spread of measuring FH/occ in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
FH/MP2
dg Mean S.D
Saudi Class 27.7 4.8
N.A.C 28.8 4.4
B.C 25.1 4.8
t-value1 (Saudi-NAC) = 2.75
Level of significance – **
t-value2 (Saudi-BC) = 6.5
Level of significance – ***
FH/occ
dg Mean S.D
Saudi Class 13.5 4.9
N.A.C 10.8 3.7
B.C 9.8 4.0
t-value1 (Saudi-NAC) = 6.5
Level of significance – ***
t-value2 (Saudi-BC) = 9.0
Level of significance –***
![Page 160: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/160.jpg)
160
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b. The vertical relationship … (continued)
Table 5.4.1.b.5 The mean and spread of measuring Y-axis angle in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.1.b.6 The mean and spread of measuring the facial axis angle in
degrees recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
Y Axis Angle
dg Mean S.D
Saudi Class 60.0 3.1
N.A.C 60.6 3.7
B.C 56.9 3.5
t-value1 (Saudi-NAC) = 2.30
Level of significance – *
t-value2 (Saudi-BC) = 11.92
Level of significance – ***
Facial axis angle
dg Mean S.D
Saudi Class 92.4 4.0
N.A.C NR NR
B.C 89.3 4.4
t-value2 (Saudi-BC) = 9.3
Level of significance – ***
![Page 161: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/161.jpg)
161
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b. The vertical relationship … (continued)
Table 5.4.1.b.7 The mean and spread of measuring gonial angle in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Gonial Angle
dg Mean S.D
Saudi Class 126.8 6.4
N.A.C 126.9 4.6
B.C 131.1 4.2
t-value1 (Saudi-NAC) = 0.18
Level of significance – NS
t-value2 (Saudi-BC) = 7.9
Level of significance – ***
![Page 162: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/162.jpg)
162
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b. The vertical relationship … (continued)
Table 5.4.1.b.8 The mean and spread of measuring ANS-Me in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.1.b.9 The mean and spread of measuring N-Me in mm recorded
for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
ANS-Me
mm Mean S.D
Saudi Class 57.2 4.3
N.A.C 65.8 4.6
B.C 58.1 4.5
t-value1 (Saudi-NAC) = 23.8
Level of significance – ***
t-value2 (Saudi-BC) = 2.5
Level of significance – *
N-Me mm Mean S.D
Saudi Class 103.7 5.6
N.A.C 116.2 6.4
B.C 104.1 5.0
t-value1 (Saudi-NAC) = 26.80
Level of significance – ***
t-value2 (Saudi-BC) = 0.85
Level of significance – NS
![Page 163: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/163.jpg)
163
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b. The vertical relationship … (continued)
Table 5.4.1.b.10 The mean and spread of measuring S-Go in mm recorded
for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.1.b.11 The mean and spread of measuring ramus height in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
S-Go
mm Mean S.D
Saudi Class 65.6 5.0
N.A.C 71.1 4.4
B.C 65.2 4.1
t-value1 (Saudi-NAC) = 13.0
Level of significance – ***
t-value2 (Saudi-BC) = 0.9
Level of significance – NS
Ramus Height
mm Mean S.D
Saudi Class 38.9 3.6
N.A.C 42.3 3.1
B.C 38.9 3.1
t-value1 (Saudi-NAC) = 11.33
Level of significance – ***
t-value2 (Saudi-BC) = 0
Level of significance – NS
![Page 164: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/164.jpg)
164
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.1 The skeletal relationship … (continued)
5.4.1.b. The vertical relationship … (continued)
Table 5.4.1.b.12 The mean and spread of measuring ANS-Me/N-Me
percentage recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
Table 5.4.1.b.13 The mean and spread of measuring S-Go/N-Me in
percentage recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
ANS-Me/N-Me % Mean S.D
Saudi Class 55.1 2.3
N.A.C NR NR
B.C 52.7 1.1
t-value2 (Saudi-BC) = 12.6
Level of significance – ***
S-go/N-Me % Mean S.D
Saudi Class 63.3 4.2
N.A.C NR NR
B.C 64.8 4.0
t-value2 (Saudi-BC) = 4.28
Level of significance – ***
![Page 165: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/165.jpg)
165
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.2 The cranial base
Table 5.4.2.1 The mean and spread of measuring S-N in mm recorded for
class I of Saudi female, North American Caucasian and British caucaisian.
The t- value of the mean difference of (Saudi-NAC) and (Saudi-BC) is
shown with its level of significance
Table 5.4.2.2 The mean and spread of measuring S-Ar in mm recorded for
class I of Saudi female, North American Caucasian and British caucaisian.
The t- value of the mean difference of (Saudi-NAC) and (Saudi-BC) is
shown with its level of significance
S – N mm Mean S.D
Saudi Class 64.3 2.7
N.A.C 74.3 3.0
B.C 64.2 1.9
t-value1 (Saudi-NAC) = 43.4
Level of significance – ***
t-value2 (Saudi-BC) = 0.43
Level of significance – NS
S-Ar mm Mean S.D
Saudi Class 29.8 2.9
N.A.C 33.0 3.7
B.C 30.5 3.0
t-value1 (Saudi-NAC) = 13.06
Level of significance – ***
t-value2 (Saudi-BC) = 2.91
Level of significance – **
![Page 166: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/166.jpg)
166
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.2 The cranial base … (continued)
Table 5.4.2.3 The mean and spread of measuring saddle angle in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
5.4.2 The Maxilla
Table 5.4.3.1 The mean and spread of measuring SNA in degrees recorded
for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Saddle Angle dg Mean S.D
Saudi Class 123.5 5.3
N.A.C NR NR
B.C 124.7 4.4
t-value2 (Saudi-BC) = 2.72
Level of significance – **
SNA dg Mean S.D
Saudi Class 80.8 3.7
N.A.C 81.1 3.8
B.C 79.9 3.4
t-value1 (Saudi-NAC) = 0.95
Level of significance – NS
t-value2 (Saudi-BC) = 2.87
Level of significance – **
![Page 167: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/167.jpg)
167
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.2 The Maxilla … (continued)
Table 5.4.3.2 The mean and spread of measuring A/N ┴ FH in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.3.3 The mean and spread of measuring maxillary length in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
A/N ┴ FH mm Mean S.D
Saudi Class -1.9 3.2
N.A.C NR NR
B.C 0.9 3.0
t-value2 (Saudi-BC) = 10.3
Level of significance – ***
Maxillary length mm Mean S.D
Saudi Class 74.9 4.4
N.A.C NR NR
B.C 78.2 3.0
t-value2 (Saudi-BC) = 8.91
Level of significance – ***
![Page 168: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/168.jpg)
168
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.4 The mandible
Table 5.4.4.1 The mean and spread of measuring SNB in degrees recorded
for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.4.2 The mean and spread of measuring facial angle in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
SNB dg Mean S.D
Saudi Class 77.7 3.5
N.A.C 77.3 3.9
B.C 77.0 3.4
t-value1 (Saudi-NAC) = 1.37
Level of significance – NS
t-value2 (Saudi-BC) = 2.39
Level of significance – *
Facial Angle dg Mean S.D
Saudi Class 86.4 3.2
N.A.C 84.6 2.7
B.C 88.7 3.2
t-value1 (Saudi-NAC) = 6.66
Level of significance – ***
t-value2 (Saudi-BC) = 8.51
Level of significance – ***
![Page 169: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/169.jpg)
169
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.4 The mandible … (continued)
Table 5.4.4.3 The mean and spread of measuring mandibular body length
in mm recorded for class I of Saudi female, North American Caucasian and
British caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.4.4 The mean and spread of measuring mandibular length in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Mandibular body length
mm Mean S.D
Saudi Class 60.3 4.1
N.A.C 70.6 3.9
B.C 63.3 3.5
t-value1 (Saudi-NAC) = 30.29
Level of significance – ***
t-value2 (Saudi-BC) = 8.82
Level of significance – ***
Mandibular length mm Mean S.D
Saudi Class 94.4 5.1
N.A.C 113.4 4.7
B.C 101.3 4.2
t-value1 (Saudi-NAC) = 44.1
Level of significance – ***
t-value2 (Saudi-BC) = 16.04
Level of significance – ***
![Page 170: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/170.jpg)
170
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.4 The mandible … (continued)
Table 5.4.4.5 The mean and spread of measuring Pog/N ┴ in mm recorded
for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.4.6 The mean and spread of measuring Pog/NB in mm recorded
for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Pog/N ┴ mm Mean S.D
Saudi Class -8.1 6.0
N.A.C NR NR
B.C -1.8 5.6
t-value2 (Saudi-BC) = 12.6
Level of significance – ***
Pog/NB mm Mean S.D
Saudi Class 0.8 1.2
N.A.C 1.2 1.2
B.C 1.6 1.9
t-value1 (Saudi-NAC) = 4.0
Level of significance – ***
t-value2 (Saudi-BC) = 8.0
Level of significance – ***
![Page 171: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/171.jpg)
171
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.5 The dentoalveolar relationship
5.4.5.a Maxillary incisor position
Table 5.4.5.a.1 The mean and spread of measuring UIE/NA in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.5.a.2 The mean and spread of measuring UIE/A ┴ FH in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
UIE/NA mm Mean S.D
Saudi Class 5.9 2.2
N.A.C 3.9 2.4
B.C 3.3 1.9
t-value1 (Saudi-NAC) = 11.1
Level of significance – ***
t-value2 (Saudi-BC) = 14.1
Level of significance – ***
UIE/A ┴ FH mm Mean S.D
Saudi Class 4.3 2.3
N.A.C NR NR
B.C 0.7 3.0
t-value2 (Saudi-BC) = 18.94
Level of significance – ***
![Page 172: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/172.jpg)
172
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.5 The dentoalveolar relationship … (continued)
5.4.5.a Maxillary incisor position … (continued)
Table 5.4.5.a.3 The mean and spread of measuring UIE/A pog in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.5.a.4 The mean and spread of measuring UIA-UIE/NA in
degrees recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
UIE/A Pog mm Mean S.D
Saudi Class 6.9 2.3
N.A.C 6.5 2.7
B.C 4.5 2.0
t-value1 (Saudi-NAC) = 2.10
Level of significance – *
t-value2 (Saudi-BC) = 12.63
Level of significance – ***
UIA-UIE/NA dg Mean S.D
Saudi Class 25.6 5.8
N.A.C 24.8 6.1
B.C 22.0 6.4
t-value1 (Saudi-NAC) = 1.6
Level of significance – NS
t-value2 (Saudi-BC) = 7.34
Level of significance – ***
![Page 173: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/173.jpg)
173
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.5 The dentoalveolar relationship … (continued)
5.4.5.b Mandibular incisor position
Table 5.4.5.b.1 The mean and spread of measuring LIE/NB in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.5.b.2 The mean and spread of measuring LIE/A pog in mm
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
LIE/NB mm Mean S.D
Saudi Class 6.6 2.0
N.A.C 4.5 2.3
B.C 3.3 2.4
t-value1 (Saudi-NAC) = 13.12
Level of significance – ***
t-value2 (Saudi-BC) = 20.62
Level of significance – ***
LIE/A Pog dg Mean S.D
Saudi Class 3.6 2.2
N.A.C 1.6 2.3
B.C 1.1 2.3
t-value1 (Saudi-NAC) = 11.11
Level of significance – ***
t-value2 (Saudi-BC) = 13.88
Level of significance – ***
![Page 174: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/174.jpg)
174
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.5 The dentoalveolar relationship … (continued)
5.4.5.b Mandibular incisor position … (continued)
Table 5.4.5.b.3 The mean and spread of measuring LIE-LIA/NB in degrees
recorded for class I of Saudi female, North American Caucasian and British
caucaisian. The t- value of the mean difference of (Saudi-NAC) and
(Saudi-BC) is shown with its level of significance
Table 5.4.5.b.4 The mean and spread of measuring LIA-LIE/MP2 in
degrees recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
LIE-LIA/NB dg Mean S.D
Saudi Class 30.4 5.5
N.A.C 25.3 6.0
B.C 23.9 7.5
t-value1 (Saudi-NAC) = 11.0
Level of significance – ***
t-value2 (Saudi-BC) = 14.1
Level of significance – ***
LIA-LIE/MP2 dg Mean S.D
Saudi Class 97.0 5.9
N.A.C 93.4 5.8
B.C NR NR
t-value1 (Saudi-NAC) = 7.2
Level of significance – ***
![Page 175: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/175.jpg)
175
5.4 Comparison of skeleto dental characteristics … (continued)
5.4.5 The dentoalveolar relationship … (continued)
5.4.5.b Mandibular incisor position … (continued)
Table 5.4.5.c.1 The mean and spread of measuring interincisal angle in
degrees recorded for class I of Saudi female, North American Caucasian
and British caucaisian. The t- value of the mean difference of (Saudi-NAC)
and (Saudi-BC) is shown with its level of significance
Interincisal Angle dg Mean S.D
Saudi Class 120.6 9.1
N.A.C 126.9 9.1
B.C 131.7 10.5
t-value1 (Saudi-NAC) = 8.18
Level of significance – ***
t-value2 (Saudi-BC) = 14.4
Level of significance – ***
![Page 176: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/176.jpg)
176
6.0 Discussion
![Page 177: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/177.jpg)
177
6.0 Discussion
The discussion of this study will have the division as the previous part
(5.0). It begins with a discussion of the material and method.
6.1 Material and method used:
This retrospective cephalometric study, was based on cephalometric
radiographs collected previously, so most of the variables and criteria used
in taking the radiographs were previously established. However, it was
decided to take a subset of the Saudi sample from the large pool of the
radiographs, and certain criteria were set in order to select the sample for
the study. The criteria applied were principally concerned with the quality
of the radiographs which received first priority in selection because poor
quality radiographs would give poor results. First molar should be in
occlusion, because this would ensure that the occlusion or vertical
relationship of all subjects is standardized. Further, there should no
previous orthodontic treatment, and, there should be no cleft or craniofacial
deformity, in order to ensure the normal position of the jaws and teeth for
investigation and evaluation. The age of the subjects were in the range
from 10-12 years which the most probable age for the peak of pubertal
growth spurt, as documented by (Burstone, 1958; Graber, 1972 and
AIAmoudi et al., 1996).
![Page 178: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/178.jpg)
178
It was well recognized scientific procedure when planning research
which requires frequent measurement, to determine the error which may
affect the results. Many authors such as Young (1962); Guilford and
Fruchter (1984); and Barford (1990) had described two types of errors
which can occur: systematic and random. In this study, which involves
measurements, these errors cannot be ignored. The systematic errors were
controlled by using only one cephalostat, two operators were involved, and
the development and storage of cephalograms were standardized. Further,
the magnification factors were determined and taken into account when the
results of this project were interpreted. The magnification factor was found
to be 10.6%, a value in general agreement with that reported by Baumrind
and Frantz (1971); Midtgard et al. (1974); Houston et al. (1986); Sandler,
1988). The strictly established criteria for selecting the radiographs require
Such criteria helped in minimizing the landmark identification error, and in
unifying the procedure.
6.2 The method error and reliability
The method error of this study was' evaluated by using well
established statistical procedure described by Dahlberg (1940) known' as
double determination method error, and also by using the coefficient of
![Page 179: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/179.jpg)
179
reliability as described by Guilford and Fruchter (1984). The first method
will determine the error of a single measurement in recording the angular,
linear and proportional parameters. The coefficient of reliability will
determine the correlation between the first set and the second set of
measurements. These statistical procedures were employed to determine
the intra-examiner and inter-examiner error. In designing this study, thirty
radiographs were retraced by the investigator and the supervisor at
different occasions. The method error was determined and found to range
for the intra-examiner variation from 0.417° to 1.468° for angular
measurements, from 0.404 mm to 0.711 mm for linear measurements, and
from 0.447% to 0.531 % for proportional measurements. The inter-
examiner method-error ranged from 0.698° to 2.912° for angular
measurements, from 0.662mm to 1.144mm for linear measurements and
from 0.768 % to 0.877 % for proportional measurements. Any reading
more than 1.2 should be considered as large error and the reading should
be underestimated (Dahlberg, 1940). From the Tables 5.1.1, 5.1.2 and
Table 5.1.3 the only readings found to have values more than 1.2 were
1.432° for SN/occ and 1.468° for FH/occ. These readings were related to
the occlusal plane, which is usually associated with large errors. ' This is in
agreement with the results obtained by Hatton and Grainger (1958); Miller
et al. (1966); Savara et al. (1966); Baumrind and Frantz (1971); Stabrun
and Danielsen (1982). The situation was slightly different when the inter-
examiner error was evaluated. The following readings were found to have
![Page 180: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/180.jpg)
180
values more than 1.2°: SN/occ of 2.869°, FH/occ of 2.912°, LIA-LIE/MP2
of 1.432°, LIE- LIA/NB of 1.472°, interincisal angle 1.469°, Pog/N ┴ FH
of 1.484 mm. The greater error values were not surprising, because in any
research, the inter-examiner error was usually larger than intra-examiner
error as reported by Hixon (1960); Broadway et al. (1962), Bennett and
Smales (1969); Kvam and Krogstad (1972). Further, the support for
method error which comes from the coefficient of reliability showed a very
high correlation value except for the following reading of SN/occ of 0.546°
and FH/occ of 0.513° in inter-examiner error. However, Houston (1983)
mentioned that when considering the coefficient of reliability, any reading
below 0.9 should be treated with suspicion. Following this criterion, the
following parameters should be considered very carefully: for intra-
examiner, SN/occ = 0.895°, FH/occ = 0.894°; for inter-examiner, angular
measurements SNA = 0.899°, LIA-LIE/MP2 = 0.896°, UIA-UIE/NA =
0.893°, LIE-LIA/NB = 0.885°, interincisal = 0.896°; and for linear
measurements A/N ┴ FH of 0.892mm, Pog/N ┴ FH of 0.885mm, Go-me
of 0.892mm.
6.3 The skeletal classification of Saudi sample
The widely accepted use of the ANB angle as a method for skeletal
classification (Taylor and Hitchcock, 1966; Freeman, 1981) was adopted in
this study. An ANB mean value of 2.9° with a standard deviation of 2.4°,
accepted as a representation of white caucasian by Bhatia and Leighton
(1993), was taken as a normal for the ANB value. As it has been
![Page 181: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/181.jpg)
181
mentioned before, the Arabian population belongs to the caucasian
(Masoud, 1981). Bhatia and Leighton (1993) was preferred to the other
main reference (Riolo et al., 1974) because it covered a larger sample size.
The frequency of skeletal discrepancy among the 205 Saudi females
was found in class I; 140 out of 205; for class II; 33, and for class III 32;
that is, by percentage 68.3%, 16.1 % and 15.6%, respectively. These
figures follow the generally observed data that class I would be the largest,
in a sample followed by class II and class III (Luffingham and Campbell,
1974; Farawana, 1987; and Jones, 1987).
In this sample, the cases with a class III skeletal relation was larger
than that in the western populations, which has a percentage less than 5 %
(Angle, 1907; Ainsworth, 1925; Seipel, 1946; Bjork, 1947; Krogman,1951;
Walther, 1960; Ast et al., 1965; Haynes, 1970; Magnusson, 1976;
Hannuksela, 1977; Gardiner, 1982). On the other hand, this incidence of a
high-class III skeletal relationship in Saudi females was in agreement with
previous studies carried out on Saudi samples. For example, when Jones
(1987) did study consisted of both sexes, he found class I to be 46.4 % of
his sample, class 11 27.5 % and class III 26.1 %. Similarly, when Toms
(1989) studied class III, he found the percentage to be 9.4%.
![Page 182: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/182.jpg)
182
6.4 The skeleto-dental characteristics of class II and class III
among Saudi sample
6.4.1 Skeletal relationship
6.4.1.a Antero posterior skeletal relationship
The mean value of ANB in class II was 7.0° and in class I was 3.1°
with a difference of + 3.9, ° indicating a class II arrangement skeletal base.
Class III showed a mean value of -0.5° with a difference of -3.6° indicating
class III skeletal arrangement. The same approach can be applied for A-B
plane angle and angle of convexity. These results obtained were in
agreement with most reported studies previously (Harris, 1965; Horowitz
et al., 1969; Dietrich, 1970; Ahlgren, 1970; Harris et al., 1972; Hitchcock,
1973; Jacobson et al., 1974; Guyer et al., 1986; and Sarhan and Hashim,
1994).
6.4.1.b Vertical skeletal relationship
The results showed no significant difference between the three
skeletal classes. These findings were in agreement with Sanborn (1955);
Harris et al. (1972); Hitchcock (1973); Williams and Andreson (1986).
However, when each variable was tested separately, SN/MP1 revealed less
value for class III, than class I with significant level of difference. The
same was true for SN/occ. Thus there is, a significant difference between
class I and class III, but no significant difference was observed between
class I and class II for both variables.
When the posterior vertical dimension was assessed linearly and
proportionally, it showed no difference between class I and the two other
classes except for the short ramus height in class II cases (Tables 5.3.1.b.10
![Page 183: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/183.jpg)
183
to 5.3.1.b.13), which was 1.5° less than class I. This finding was consistent
with Smeets (1962). The significant difference of short ramus height may
have implications for the arrangement of skeletal bases in other dimensions
and this will be investigated further. It should be noted that the analysis of
Y-axis angle and facial axis angle (Table 5.3.1.b.5 and Table 5.3.1.b.6)
showed a significant difference between class II and class III when they
were compared to class I separately. The Y-axis angle and facial axis angle,
as mentioned by Down (1948) and Ricketts (1960), indicate the direction of
mandibular growth. This can be described generally in this study as being
a downward and backward rotation of the mandible for class II and an
upward and forward rotation for class Ill. This finding is in agreement with
Drelich (1948); Dietrich (1970); Hitchcock (1973); McNamara (1981);
Hashim and Sarhan (1993); Sarhan and Hashim (1994).
6.4.2. Cranial base
The cranial base were assessed by linear and angular measurements.
The anterior cranial base, representing the measurement from point N to
point S, showed no significant difference between class II and class III.
This finding is in agreement with other investigators (Guyer et al., 1986;
Hashim and Sarhan, 1993; Sarhan and Hashim, 1994). Generally it was
noticed that class II had slightly larger cranial base, whereas, class III had
slightly shorter base. In this study, the result of the measurement for the
posterior cranial base from point S to Ar showed no statistical differences
between the three classes. The cranial base angle also showed no
![Page 184: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/184.jpg)
184
significant differences between the three classes, this finding in agreement
with Guyer et al. (1986); Hashim and Sarhan (1993); Sarhan and Hashim
(1994). However, it was noticed from the mean value (Table 5.3.2.3) in
class II was slightly larger than the mean value in class I. This finding was
similar to the findings reported by Jarvinen (1984) who found class II
usually have high angle, and in contrast to the findings of Harris (1965)
who found smaller angle in class II. Further, class III had a smaller mean
value than class I. This was in agreement with Bjork (1947); Sanborn
(1955); Horowitz et al. (1969); Rakosi (1970).
6.4.3 Maxilla
In this study, both maxillary position and length were assessed. The
position of the maxilla relative to cranial base was assessed by two
variables. The first variable was SNA. The Saudi sample showed a mean
value of 80.8° for class I, 83.3° for class II, and 78.6° for the class III
skeletal relationship. It can be observed that class II is 2.5° more than class
I. This may indicate that the maxilla is protruded for class II. On the other
hand, for the class III skeletal relationship the mean value was 2.2° less
than class I, which would also indicate retrusive maxilla. The above finding
was supported by the second variable: the measurement from point A to
A/N ┴ FH. This has the following mean values: -1.9 mm, 0.3 mm, and -3.9
mm, for class I, class II, class III respectively. When maxillary length was
considered, the values were 74.9 mm for class I, 76.6 mm for class II, and
72.4 mm for class III. This finding indicated that class II had longer
![Page 185: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/185.jpg)
185
maxilla and class III had shorter maxilla than class I. The findings for class
II were in agreement with Drelich (1948); Blair (1954); Altemus (1955);
Rothstein (1971); Amoric (1985); Rosenblum (1995). On the other hand,
Elsasser and Wylie (1943); Riedel (1952); Hunter (1967), and Hitchcock
(1973) found slightly different results. Their main finding was that the
maxilla was normal. The other researchers as Renfroe (1948); Henry
(1957); Harris et at. (1972); McNamara (1981), found the maxilla to be
retrusive. The results of class III were similar to those of Bjork (1947);
Sanborn (1955); Jacobson et al. (1974); Williams and Anderson (1986);
Guyer et al. (1986), while Horowitz et al. (1969) found normal maxilla in
class III.
6.4.4 Mandible
Similar to maxilla, the mandibular position and size were determined,
in addition to that the chin prominence was measured. The position of the
mandible relative to the cranial base was assessed by several variables. The
SNB angle gave the readings of 77.7°, 76.3°, and 79.2° for class I, class II,
and class III, respectively. This indicated that the mandible had a retruded
position for class II and relatively protruded in class III. When facial angle
was considered, the values of 86.4° for class I, 84.5° for class II and, 87.4°
for class III were obtained indicating that the mandible was retruded for
class II and normal for class III. On the other hand, when the linear
measurement Pog/N ┴ FH was assessed, the finding showed that the
mandible was retrusive in class II and protrusive in class III.
![Page 186: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/186.jpg)
186
The mandibular length was also considered. For the measurement of
body length, class I has a value of 60.3 mm; class II 59.2 mm, and class III,
61.5 mm. The total mandibular length including the ramus height had a
value of 94.4 mm, 91.9 mm, and 95.1 mm, for class I, class II and class III,
respectively. This finding showed that, for class II the body length of the
mandible was normal, whereas, the total length of the mandible was
slightly less than normal. This may be due to a short ramus. In class III,
however, the body length and total mandibular length were found to be
normal.
The above results may indicate that the mandible had a relatively
normal position and normal size in the saudi sample for class III, and a
retruded mandibular position and normal size in class II. To assess the
prominence of the chin, the linear measurement between the line NB and
point Pog was investigated for class II and class III in relation to class I.
The findings demonstrated a retruded chin point for class II, whereas, class
III showed no significant difference when compared to class I. The
findings for class II were in agreement with Elsasser and Wylie (1943);
Renfroe (1948); Drelich (1948); Nelson and Highly (1948); Gilmore
(1950); Craig (1951); Riedel (1952); Henry (1957); Hunter (1967); Harris
et al., (1972); Hitchcock (1973); McNamara (1981). The opposite was
found by Adams (1948); Blair (1954); Altemus (1955); Rothstein (1971),
who found a normal mandible. The finding of this study for class III agreed
with Dietrich (1970); Ellis and McNamara (1984); Williams and Anderson
(1986).
![Page 187: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/187.jpg)
187
When considering the relative position of the maxilla and the
mandible and their sizes, it was concluded that class II has a protruded
maxilla, and retrusive mandible, whereas, class III has retrusive maxilla
and relatively normal mandibular position and size. These results suggest
accepting the research hypothesis "the skeletal discrepancies of class II and
class III skeletal relationship were attributed mainly to a positonal and/or a
dimensional cause".
6.4.5 Dento-alveolar relation
The dento-alveolar relationship was assessed for maxillary and
mandibular incisor position and relation using both angular and linear
measurement.
6.4.5.1 Maxillary incisor position
The linear measurement of the tip of upper incisor to a predetermined
reference line showed retrusion of the tip of the upper incisor in the class II
skeletal relationship (Tables 5.3.5.a.1 to 5.3.5.a.3) and protrusion in class
III cases. The differences between the mean values of class I to the other
classes showed a high level of significance except for the position of upper
incisor teeth in relation to A-Pog line in class III cases. This may be due to
the position of point Pog in class III being forward. In class II cases, the
position of upper incisor in relation to A-Pog line has greater value than
class I. This agreed with the finding of Hunter (1967); Rothstein (1971);
Harris et al. (1972); Hitchcock (1973); and McNamara (1981). The
![Page 188: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/188.jpg)
188
literature reported some controversy regarding the position of the upper
incisor for class II and class III. The result of this study was similar to the
finding of Bjork (1947); Dietrich (1970); Rakosi (1970); Jacobson et al.
(1974); Moss (1976); Guyer et al. (1986); and Toms (1989), for class III
cases. Similar results of this study was reported by Jones (1987) for class II
But it was in disagreement with Henry (1957) who found that the
maxillary incisors were normal. The angular measurements of upper
incisor teeth measured between the long axis of upper incisor and NA line
(see Table 5.3.5.a.4) confirmed the retroclination of upper anterior teeth in
class II cases. The mean value in class II was 22.30 class I 25.6
0 and class
III 32.0.0 This indicated retroclination of upper incisor in class II and
proclination in class III. These findings agreed with the theory proposed by
Bjork (1947); Robinson et at. (1972); Waite and Worms (1974); Worms et
al. (1976); Thomas et al. (1977); Solow (1980), that teeth tend to
compensate for the underlying skeletal discrepancy by changing their
angulation. According to this theory, the upper anterior teeth are expected
to be retroclined in class II and proclined in class III. The finding of this
study is in full agreement with this theory.
6.4.5.2 Mandibular incisor position
Similar to the upper incisors, the lower incisors were measured by
linear and angular parameters. The linear position of the tip of lower
incisor teeth in relation to the NB line (Table 5.4.5. b.1. and Table
5.4.5.b.2) showed proclination of lower incisor teeth in class II and slight
![Page 189: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/189.jpg)
189
retroclination in class III. The mean values were 6.6°, 8.4° and 5.1° for
class I, class II and class III respectively, with highly significant
differences between class I, and class II, and between class I and class Ill.
The position of the lower incisor in relation to A-Pog line showed very
slight variation between the three classes with slight retroclination in class
II and very slight proclination in class III. This may be due to the influence
of the lower lip and the tongue. The mean value of the angular
measurement of the position of the lower incisor teeth showed proclination
of lower incisor teeth in class II and retroclination in class III (Tables
5.3.5.b.3 and 5.3.5.b.4). These findings were in agreement with the
findings of Bjork (1947); Worms et al. (1976); Thomas et at: (1977);
Solow and Tallgren (1977); Solow (1980), Jones (1987) Toms (1989).
6.4.5.3 Inter incisal angle
The inter-incisal angle is the most commonly used measurement for
the relationship of upper incisor teeth to the lower incisor teeth. In this
study, the mean value of the inter-incisal angle in class I was 120.6°
9.1°, class II, 117.2° 9.6° and class III 121.9° +7.8°. The difference in
this angle was significant when class I was compared to class II, and not
significant when class III was compared to class I. This result could be
attributed to the compensatory mechanism caused by the underlying
skeletal discrepancy. Other influential factors e.g. lip position and
morphology, tongue position and size, etc. should not be ignored.
However, firm conclusion can not be stated. A soft tissue study may be of
![Page 190: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/190.jpg)
190
great help in explaining this relationship.
6.5 Comparison of the skeleto-dental characteristics of
Saudi females to the established cephalometric
standards
The results of the present study could be of great value for the
orthodontist in the diagnosis and treatment plan when treating Saudi
patients. However, the results would be invaluable when compared with
well-known cephalometric studies. This could add more informations to
the literature and help for future studies.
In this study, the results obtained for the Saudi females with skeletal
class I were compared to the most widely known studies, namely Riolo et
al. (1974) and Bhatia and Leighton (1993). The results of comparison were
presented in Tables 5.4.1.a.1 to 5.4.5.c.1.
6.5.1 Skeletal relationship
6.5.1.a Antero-posterior skeletal relationship
Although the ANB (2.9°+ 2.4°) reported by Bhatia and Leighton
(1993) was used in the skeletal classification of the Saudi sample. The
result of comparing the Saudi females to British Caucasian showed
significant differences. Similarly, significant difference between Saudis
and North American caucasian data were observed. The level of
significance was very high (P<0.001) for the North American (Table
5.4.1.a.1). Further, when the A-B plane angle was used to compare
between the Saudi and the other two groups, the level of significance was
![Page 191: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/191.jpg)
191
very high (P < 0.001) between Saudi, British and North American. No
significant difference was observed in the angle of convexity between
Saudi females and the British Caucasians, whereas, it was significant (P <
0.001) when compared to North American Caucasians. These differences
between the three groups could be due to the variation in samples. This
finding will not suggest rejecting the stated hypothesis that "Saudi Arabian
population belong to Caucasian race, but that then they should have similar
skeleto-dental characteristics". When the skeletal relationship of the same
ethnic sub-group was compared by different investigators, a similar finding
to this study was reported (Miura, 1968; Chan, 1972); Richardson, 1980;
and Haralabakis et al., 1983).
6.5.1.b Vertical relationship
The angular measurements of the various vertical skeletal
relationships showed significant differences between class I skeletal
relationship of Saudi sample when compared to North American Caucasian
and British Caucasian except when the gonial angle in the Saudi sample
was compared to the North American (Tables 5.4.1.b.l to 5.4.1.b.7). There
was no significant difference between the Saudi female and British
Caucasian when comparing total anterior facial height, total posterior facial
height and ramus height. On the other hand, significant differences at 0.1 %
level was observed when the Saudi was compared to the North American
(Tables 5.4.1. b. 9 to 5.4.1b/11). The lower facial height measured from
ANS to Me (Table 5.4.1.b.8) showed a significant difference between
![Page 192: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/192.jpg)
192
Saudi and both North American and British samples, which indicates that
the Saudi sample has relatively less excessive vertical anterior'
development. In general, the comparison of Saudi to North American
sample was highly significant. The comparison of vertical height
proportion also showed highly significant difference between the Saudi and
British Caucasian samples. This difference may be due to the variation in
the samples.
6.5.2 Cranial base
The linear measurements of the cranial base showed no significant
differences between the Saudi female and British caucasian for anterior
cranial base (Table 5.4.2.1). Posterior cranial base revealed significant
difference between the Saudi female and the North American and the
British samples. The saddle angle (measured from NS to Ar) showed
significant difference between the Saudi females and British samples
(Table 5.4.2.3). Such comparison was reported in different studies (Bjork,
1947) and the results were controversial. This could be due to variation in
the samples or landmark identification.
6.5.3 Maxilla
The relative position of maxilla (SNA) was significantly different
between the Saudi females and British Caucasian. No difference was
observed when Saudi females were compared to North American sample
(Table 5.4.3.1). The Saudi females showed a short maxilla when compared
![Page 193: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/193.jpg)
193
to the British Caucasians (P < 0.001).
6.5.4 Mandible
Measurements of the mandibular position and size in both angular
and linear measurements showed significant differences between Saudi,
British and North Americans samples (P < 0.001). The SNB angle did not
show significant difference between Saudi and North American samples
(Table 5.4.4.1). However, a significant difference at 5% level was observed
when the Saudi females compared to the British Caucasian.
6.5.5 Dento-alveolar relationship
The dentoalveolar relationship was studied to see if there was any
difference in the position and relation of the incisor teeth between the saudi
female and British and North American caucasian (Tables 5.4.5.a.1 to
5.4.5.c.1). The results showed statistically significant differences in all
variables studied. However, no significant difference was observed when
the upper central incisor inclination in Saudi females was compared to the
British Caucasian (Tables 3.4.5.a.1 to 5.4.5.c.1). The results of the dento-
alveolar relationship in the Saudi females revealed that there was more
protrusion in the incisor teeth than the British and North American
Caucasian. This finding was in agreement with studies carried out in other
Saudi samples (Shalhoub et al., 1987; Sarhan and Nashashibi, 1988; Toms,
![Page 194: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/194.jpg)
194
1989; and Nashashibi et al., 1990). When comparing the skeleto-dental
characteristics features of the Saudi females to the established means for
British and North American Caucasians, it was found that the Saudi female
was nearer to the British sample than the North American Caucasian.
![Page 195: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/195.jpg)
195
7.0 CONCLUSIONS
![Page 196: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/196.jpg)
196
7.0 Conclusions
1. The results of this study suggest accepting the hypotheses, that the
Saudis belong to the Caucasian and that the discrepancy in the
skeletal relationship was attributed to positional and/or dimensional
variations.
2. The Saudi sample showed a higher prevalence of class III than the
British and North American Caucasians.
3. Skeletal class II was found to be due to both protruded maxilla and
retruded mandible.
4. Skeletal class III was observed to be due to a retruded maxilla and
relatively normal mandible.
5. The Y-axis and facial axis angles indicate that the mandibular
rotation for class II was in a backward direction, whereas, for class III
in a forward direction.
6. In the vertical relationship, significant difference was observed in
most of the compared variables between the Saudi and British and
North American samples.
7. Dento-alveolar compensation was observed in class II (retruded
upper incisor and protruded lower incisor) and class III (protruded
upper incisor, and retruded lower incisor).
![Page 197: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/197.jpg)
197
8. Bi-maxillary protrusion was observed when comparing the skeletal
class I of the Saudi females to the skeletal class I of the British and
North American Caucasians.
9. The skeleto-dental characteristic features of Saudi females were
nearer to the British sample than to the North American Caucasian.
![Page 198: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/198.jpg)
198
7.1. Suggestions for Future Studies
Although this study has fulfilled its aims, there are several aspects,
which should be considered in future studies. These include:
1. A large randomly selected sample of both males and females should
be collected from the different provinces of the Kingdom, with more
variables to be studied, e.g. soft tissue.
2. More sophisticated computer with advance statistical programs
should be used.
![Page 199: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/199.jpg)
199
8.0 REFERENCES
![Page 200: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/200.jpg)
200
8.0 REFERENCES
Adams JW: Cephalometric studies on the form of the human mandible.
Angle Orthod 1948; 18:8-12.
Ahlgren J: Form and function of angle class III malocclusion.
Acephalometric and electromyographic study. Trans European 1970; 77-
88.
Ainsworth NJ: The incidence of dental disease in children, Special
Report. HMS 0 1925; 97-102.
Al Amoudi N, Masoud I, Feteih R, Ardawi S, Bahnassy A:
Anthropometric measurements in school girls in the Western Region,
Saudi Arabia. Saudi Med J 1996; 17:26-31.
Al Emran S: Prevalence of mal occlusion in Saudi Arabia. An
epidemiological study of Saudi male school children [Thesis]. Bergen,
University of Bergen, 1988.
AI-Shammery AR, Guile E: The dental health system of Saudi Arabia.
Odonto Stomatol Rop 1986; 4:235-39.
Altemus LA: Horizontal and vertical dentofacial relationships in normal
and class II division I malocclusion in girls 11-15 years. Angle Orthod
1955; 25: 120-37.
Amoric M: Etude crilique des evaluation cephalometriques composant
less classes II d'angle selon McNamara. Rev Orthop Dento Fac
1985; 19:563-68.
Angle EH: The treatment of malocclusion of the teeth. 7th ed, S White
Dental Manufacturing Co, Philadephia, 1907.
Angle EH: Classification of malocclusion. Dent Cosmos 1898; 41:248- 64.
Ast DB, Carlos JP, Cons NC: The prevalence and characteristics of
mal occlusion among senior high school students in upstate New York. Am
J Orthod 1965; 51:437-45. Baccon W, Ciradin P, Turlot J: A comparison of cephalometric norms
for the African Bantu and caucasiod population. Europ J Orthod
1983; 5:223-24.
Ballard CF: Some bases for aetiology and diagnosis in orthodontic.
Trans Br Soc for the Study of Orthod 1948; 27-38.
Barford NC: Experimental measurements. Precision Error and Truth,
2nd ed, New York, Wiley 1990.
![Page 201: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/201.jpg)
201
Baum AT: A cephalometric evaluation of the normal skeletal and dental
pattern of children with excellent occlusion. Angle Orthod 1951; 21:96-
103.
Baumrind S, Frantz RD: The reliability of head film measurements
conventional angular and linear measurements. Am J Orthod 1971;
60:505-17.
Behrents R: Adult craniofacial growth. J Chin Orthod 1986; 20:842-47.
Bennett DT, Smales FC: Accuracy of angular measurements obtained
from radiographic cephalometric analysis. J Dent Res 1969; 48:595-600.
Bergersen EO: Enlargement and distoration in cephalometric
radiography. Compensation Tables For Linear Measurements. Angle
Orthod 1980; 50:230-44.
Bertram C: Course of class III in the Habsburgs. Trans Europ Orthod
Soc LD 1959; 35:295-300.
Bhatia SN, Leighton BC: A manual of facial growth. A Computer
Analysis of Longitudinal Cephalometric Growth Data. Oxford University
Press, 1993.
Bjork A: The face in profile. Svenske T and Lakar - Tid Skrift 40.
Berlingska Boktryckeriet Lund, 1947.
Bjork A: The use of metallic implants in the study of facial growth in
children: method and application. Am J of Phy Anthrop 1968; 29:243-54.
Bjork A, Skieller V: Facial development and tooth eruption: An
implant study of the age of puberty. Am J Orthod 1972; 62:339-83.
Bjork A, Skieller V: Growth in the width of the maxilla studied by the
implant method. Scand J of Plastic and Reconstr Surg 1974; 8:26-33.
Blair ES: A cephalometric roentyenographic appraisal of the skeletal
morphology of class I, class II, div. I, and class II, div 2 (angle)
malocclusion. Angle Orthod 1954; 24:106-19.
Brehm HL., Jackson DL: An investigation of the extent of the need for
orthodontic services. Am J Orthod 1961; 47:148-49.
Broadbent BH: A new x-ray technique and its application to orthodontics.
Angle Orthod 1931; 1:45-86.
Broadway ES, Healy MJR, Poyton HG: The accuracy of tracing from
cephalometric lateral skull radiographs. Dent Practnr, 1962; 12:455-61.
![Page 202: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/202.jpg)
202
Broca P: Sure le plan horizontal de la tete et sur la method
trigonometrique. Bull Soc Anthrop Paris 1873.
Brown M: Eight methods of analysing a cephalogram to establish
anteroposterior skeletal discrepancy. Br J Orthod 1981; 8: 139-46.
Burstone CJ: The integumental profile. Am J Orthod 1958; 44: 1-25.
Camper P (1792). Cited in Fiwlay LM: Craniometry and cephalometry:
A history prior to the advent of radiography. Angle Orthod 1980; 50:312-
21.
Chan GK: A cephalometric appraisal of the chinese. Am J Orthod
1972; 16:279-85.
Christie TE: Cephalometric patterns of adults with normal occlusion.
Angle Orthod 1977; 47: 128-35.
Coon CS, Garn SM, Bersill JB: Races: A study of the problems of race
formation in man. Charles C. Thomas, Springfield, Illinois, 1950; 65-71.
Cotton WN, Takano WS, Wong WW, Wylie WL: Downs analysis
applied to three ethnic groups. Angle Orthod 1951; 21:213-20.
Crraig CE: The skeletal patterns characteristic of class I and class II,
division I malocclusion, in norma lateralis. Angle Orthod 1951; 21:44-
56.
Dahlberg A: Statistical methods for medical and biological students.
New York Interscience Publications, 1940.
Dietrich UC: Morphological variability of skeletal III relationship as
revealed by cephalometric analysis. Trans Europ Orthod Soc 1970; 131-
43.
Down WB: Variation in facial relationships; their significance III
treatment and prognosis. Am J Orthod 1948; 34:812-40.
Down WB: The role of cephalometries in orthodontic case analysis and
diagnosis. Am J Orthod 1952; 38:162-82.
Drelich RCA: Cephalometric study of untreated class II, division I
malocclusion. Angle Orthod 1948; 18:70-75.
Drummond RA: A determination of cephalometric norms for the negro
race. Am J Orthod 1968; 54:670-82.
Ellis E, McNamara JA: Components of adult Class III malocclusion.
J Oral Maxillofac Surg 1984; 42:295-305.
![Page 203: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/203.jpg)
203
EIsasser W A, Wylie WL: The craniofacial morphology of mandibular
retrusion. Am J Phys Anthrop 1943; 6:461-73.
Emrich RE, Brodie AG, Blayney JR: Prevalence of class I, class II
and class III malocclusions (angle) in an urban population: An
Epidemiological Study. J Dent Res 1965; 44:947-53.
Enlow DH: Handbook of facial growth. Philadelphia Saunders, 1975.
Enlow DH: Facial growth: 3rd ed, Saunders, 1990; 346-56.
Farawana NW: Malocclusion in Iraq. Quintessence Int 1987; 18:153-
57.
Fishman LS: Chronological versus skeletal age, an evaluation of
craniofacial growth. Angle Orthod 1979; 48:181-89.
Fonseca RJ, Klein WD: A cephalometric evaluation of American negro
women. Am J Orthod 1978; 73: 152-60.
Foster TD, Day AJW: A survey of malocclusion and the need for
orthodontic treatment in Shropshire school population. Br J Orthod
1974; 1:73-8.
Foster TD: A textbook of orthodontics, 3rd ed, Oxford, Blackwell
1990; 75-108.
Freeman RS: Adjusting ANB angles to reflect the effect of maxillary
position. Angle Orthod 1981; 51:162-71.
Gardiner JH: A survey of malocclusion and some aetiological factors
in 1000 Sheffield school children. Dent Pract and Dent Rec 1956; 6: 187-
201.
Gardiner JH: An orthodontic survey of Libyan school children. Br J
Orthod 1982; 9:59-61.
Gilmore WA: Morphology of the adult mandible in class II, division I,
malocclusion and in excellent occlusion. Angle Orthod 1950; 20: 137-46.
Giorgio M, Lucchese FP: The mandible in class II, division 2. Angle
Orthod 1982; 52:288-92.
Goldsman S: The variation in skeletal and denture patterns in excellent
adult facial types. Angle Orthod 1959; 29:63-92.
Goose DH, Thompson DG, Winter Fe: Malocclusion In school children
of the West Midlands. Br Dent J 1957; 102:174-78.
![Page 204: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/204.jpg)
204
Graber TM: Orthodontic principles and practice. 3rd ed, Saunders,
1972.
Gravely JF, Benzies PM: The clinical significance of tracing error in
cephalometry. Br J Orthod 1974; 1:95-101.
Gresham H: A cephalometric comparison of skeletal and denture pattern
components in two groups of children with acceptable occlusion. Angle
Orthod 1963; 33:114-19.
Guilford JP, Fruchter B: Fundamental statistics in psychology and
education. 6th ed, 1984.
Guo MK: Cephalometric standards of Steiner's analysis established on
Chinese children. J Formosa Med Assoc 1971; 70:97-102.
Guyer C, Ellis E, McNamara JA, Behrents R: Components of class
III malocclusion in juveniles and adolescent. Angle Orthod 1986; 7-29.
Hajighadimi M, Dougherty H, Garkani F: Cephalometric evaluation
of Iranian children and its comparison with Tweed's and Steiner’s
standards. Am J Orthod 1981; 79: 192-97.
Hannuksela A: Prevalence of malocclusion and need for orthodontic
treatment in 9 years old Finnish school children. Proceedings of the
Finnish. Dent Soc 1977; 73:21-26.
Haralabakis H: Incidence of mal occlusion among dental students at
Athens University. Trans Eur Orthod Soc 1957; 310-11.
Haralabakis B, Spiraus V, Kolokithas G: Dentofacial cephalometric
analysis in adult Greeks with normal occlusion. Europ J Orthod
1983; 5:241-43.
Harris EF, Johnson MG: Heritability of craniometric and occlusal
variables: A longitudinal Sib. Analysis. Am J Orthod Dentfac Orthop
1991; 99:258-68.
Harris JE: Craniofacial growth and malocclusion. Europ Orthod Soc
1965; 103-16.
Harris JE, Kowalski CJ, Walker GF: Discrimination between normal
and class IOI individuals using Steiner's analysis. Angle Orthod 1972;
42:212-20.
Harvold EP: Primate experiments on oral respiration. Am J Orthod
1981; 79:359-72.
Hashim AH, Sarhan OA: Dento-skeletal components of class III
![Page 205: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/205.jpg)
205
malocclusion for children with normal and protruded mandibles. J Clin
Pediat Dent 1993; 18:13-16.
Hatton ME, Grainger RM: Reliability of measurements cephalograms at
the Burlington orthodontic research centre. J Dent Res 1958; 37:853- 59.
Haynes S: The prevalence of mal occlusion in English children aged 11-
12 years. Trans Eur Orthod Soc 1970; 89-98.
Henry RG: A classification of class II, division 1, malocclusion. Angle
Orthod 1957; 27:83-92.
Hill IN, Blayney JR, Wolf N: Evanston dental caries study. Prevalence of
malocclusion of children in a fluoridated and control area. J Dent Res
1959; 38:782-94.
Hitchcock HA: A cephalometric description of class II, division 1
malocclusion. Am J Orthod 1973; 63:414-23.
Hixon EH: The norm concept and cephalometries. Am J Orthod
1956; 42:898-905.
Hixon EH: Cephalometries and longitudinal research. Am J Orthod
1960; 46:36-42.
Hofrath H (1931). Cited in Bjork A: The face In profile. Lund
Berlingska Boktryckeriet 1947.
Holdaway RA: A soft tissue cephalometric analysis and its use in
orthodontic treatment planning. Am J Orthod 1983; 84: 1-28.
Horowitz SL, Converse JM, Gerstman LT: Craniofacial relationship
in mandibular prognathism. Arch Oral Biol 1969; 14: 121-31.
Houston WJ: Assessment of the skeletal pattern from the occlsuion of
the incisor teeth: A Critical Review. Br J Orthod 1975; 2:167-69.
Houston WJB: Wather's orthodontic notes. 4th ed, Bristol, Wright
1983; 154-62. Houston, WJB: The analysis of errors in orthodontic
measurements. Am J Orthod 1983; 8:382-90.
Houston WJB, Mahrer RE, Meelroy D, Sheriff M: Sources of error
in measurements from cephalometric radiographs. Eur J Orthod
1986; 8:205-35.
Houston WJB, Tulley WJ: A textbook of orthodontics. Bristol Wright
1986; 188-91.
Hunter WS: The vertical dimension of the race and skeleto dental
![Page 206: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/206.jpg)
206
retrognathism. Am J Orthod 1967; 53:586-95.
Iyer VS, Lutz W: Cephalometric comparison of Indian and English
facial profiles. Am J Phys Anthrop 1966; 24: 117-26.
Jacobson AMDS, Evans WG, Preston CB, Sadowsky PL: Mandibular
prognathism. Am J Orthod 1974; 66:140-71.
Jacobson AMDS: The Wits appraisal of jaw disharmony. Am J Orthod
1975; 67: 125-38.
Jarvinen S: Saddle angle and maxillary prognathism: A radiological
analysis of the association between the NSAr and SNA angles. Br J
Orthod 1984; 11:209-13.
Joffe BM: Cephalometric analysis of mandibular prognathism. JDASA
1965; 15: 145-56.
Jones WB: Malocclusion and facial types in a group of Saudi Arabian
patients referred for orthodontic treatment: A Preliminary Study. Br J
Orthod 1987; 14:143-46.
Kim YH, Vietas J: Anteroposterior dysplasia indicator: An adjunct to
cephalometric differential diagnosis. Am J Orthod 1978; 73:619-33.
Kowaliski CJ, Nasjleti C, Walker GF: Differential diagnosis of
American adult male black and white populations using Steiner’s analysis.
Angle Orthod 1974; 44:346-50.
Krogman WM: The problem of timing in facial growth with special
references to the period of the changing dentition. Am J Orthod
1951; 37:253-76.
Kvam E, Krogstad O: Correspondence of cephalometric values. A
methodological study using duplicating films of lateral headplates. Angle
Orthod 1972; 42: 123-28.
Lande M: Growth behavior of the human bony facial profile as revealed
by serial cephalometric roentenology. Angle Orthod 1952; 22:78-90.
Linder-Aronson S: Adenoids. Their effect on mode of breathing and
nasal airflow and their relationship to characteristics of the facial skeleton
and the dentition. Acta Otolryng Suppl 1970; 265-72.
Litton SF, Ackerman LV, Isaacson RJ, Shapiro RBL: A genetic study
of class III mal occlusion. Am J Orthod 1970; 58:565-77.
Love RJ, Murray TM, Mamandras AB: Facial growth in males 16 to 20
years of age. Am J Orthod Dentofacial Orthop 1990; 97:200-206.
![Page 207: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/207.jpg)
207
Luffingham JK, Campbell HM: Need for orthodontic treatment. A
pilot survey of 14-year-old school children in Paisley, Scotland. Trans
Eur Orthod Soc 1974; 259-67.
Lundstrom A: Svenska tandlakare sallskapet sektion for ortodonti,
jubileumsskrift 1968; 57-59.
Magnusson TE: An epidemiological study of occlusal anomalies in
relation to development of the dentition in Iceland children. Community
Dent and Oral Epidemiol 1976;4: 121-28.
Masoud IM: A study on malocclusion among a group of Saudi Arabian
school children [Thesis]. Washington DC, Howard University, United
States, 1981.
Masoud I, AI Amoudi N, Feteih R: Cephalometric norms for
SaudiArabian school girls. The Saudi Dental Journal, 1994; 6:8.
Massler M, Frankel JM: Prevalence of mal occlusion in children aged 14-
18 years. Am J Orthod 1951; 37:751-68.
Midtgard J, Bjork G, Liner Aronson S: Reproducibility of
cephalometric landmarks and errors of measurement of cephalometric
cranial distance. Angle Orthod 1974; 44:36-61.
Miller PA, Savara BS, Singh IJ: Analysis of errors in cephalometric
measurement of three-dimensional distances on the maxilla. Angle
Orthod 1966; 36:169-75.
Mills JRE: An assessment of class III mal occlusion. Dent Pract
1966; 16:452-67.
Mills JR: Principles and practice of orthodontics. Churchill Livingstone,
Longman Group Ltd, London, 1982.
Miura F: Cephalometric standards for the Japanese according to
Steiner's analysis. Am J Orthod 1968; 5:670-82.
Montague A: Man's most dangerous myth. The Fallacy of Races, New
York, Columbia University Press, 1942.
Moss JP: The problem of the class III malocclusion. Proceedings, Royal
Soc Med 1976;69:913-22.
Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL:
Differential diagnosis of class II malocclusions. Am J Orthod
1980; 78:477-94.
Moyers RE. Handbook of orthodontics. 4th ed, Year Book Medical
![Page 208: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/208.jpg)
208
Publisher, Inc. 1988.
McCallin SG: Angle class III malocclusion. Trans British Soc for the
Study of Orthod 1955; 5:91-101.
McNamara JA Jr.: Components of class II mal occlusion in children 8- 10
years of age. Angle Orthod 1981; 51:177-202.
McNamara JA Jr.: A method of cephalometric evaluation. Am J
Orthod 1984; 86:449-69.
Nashashibi I, Darwish SK, Khalifa R: Prevalence of malocclusion and
treatment need in Riyadh (Saudi Arabia). Odontol Stomatol Trop
1983; 6:209-14.
Nashashibi lA, Shaikh HS, Sarhan OA: Cephalometric norms of Saudi
boys. The Saudi Dent J 1990; 2:52-57.
Nelson WE, Higley LB: Length of mandibular basal bone in normal
occlusion and class I malocclusion compared to class II, division 1
malocclusion. Am J Orthod 1948; 34:610-17.
Nielsen IL: Vertical malocclusion: etiology, development, diagnosis and
some aspects of treatment. Angle Orthod 1991; 61:247-60.
Niinimaa V: Oronasal distribution of respiratory airflow. Respir
Physiol, 1981; 43:69-75.
Pacini AJ, Roentgen R: Anthropometry of the skull. J Radio 1922;
42:322-418.
Pascoe JJ, Hayward JR, Costich ER: Mandibular prognathism: its
etiology and classification. J Oral Surg Anesth and Hosp Dent Serv
1960; 18:21-24.
Petrovic A: Control of post natal growth of secondary cartilages of the
mandible by mechanisms regulating occlusion. Trans Eur Orthod Soc
1974; 50:69-75.
Proffit WR: Lingual pressure patterns in the transition from tongue
thrust to adult swallowing. Arch Oral Biol 1972; 17:555-63.
Proffit WR: Contemporary orthodontics. 2nd ed, Mosby Co, 1992.
Rakosi T: The significance of Roentgenographic cephalometries in the
diagnosis and treatment of class III malocclusion. Trans Europ Orthod
Soc 1970; 155-70.
Rakosi T, Schilli MD: Class III anomalies: a coordinated approach to
![Page 209: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/209.jpg)
209
skeletal, dental and soft tissue problems. J Oral Surg 1981; 39:860-70.
Renfroe EW: A study of the facial patterns associated with class I, class II,
division 1 and class II, division 2 malocclusion. Angle Orthod
1948; 19: 12-15.
Richardson A: An investigation into the reproducibility of some points,
planes and lines used in cephalometric analysis. Am JOrthod
1966; 52:637-51.
Richardson E: Racial difference in the dimensional traits of the human
face. Angle Orthod 1980; 50:301-11.
Richardson M: Measurements of dental base relationship. Rup J Orthod
1982; 4:251-56.
Ricketts RM: The influence of orthodontic treatment on facial growth
and development. Angle Orthod 1960; 30: 103-33.
Riedel RA: Aesthetics and its relation to orthodontic therapy. Angle
Orthod 1950; 20: 168-78.
Riedel RA: The relation of maxillary structures to cranium in
mal occlusion and normal occlusion. Angle Orthod 1952; 22: 142-45.
Riolo ML, Moyers RE, McNamara JA, Hunter WS: An Atlas of
Craniofacial Growth, 1974.
Robinson SW, Speidel TM, Isaacson RJ, Worms FW: Amount of soft
tissue profile change produced by reduction of mandibular prognathism.
Angle Orthod 1972; 42:227-35.
Roentgen (1895). Cited in Farman AG: Early pioneers of oral and
maxillofacial radiology. Oral Surg Oral Med Oral Path 1995; 80:496-511.
Rosenblum RE: Class II malocclusion: mandibular retrusion or
maxillary protrusion. Angle Orthod 1995; 65:49-62.
Rothstein TI: Facial morphology and growth from 10 to 14 years of age in
children presenting class II, division 1 malocclusion. A comparative
roentgenographic cephalometric study. Am J Orthod 1971; 60:619-20.
Rowntree D: Statistics without tears. A Primer for Non-mathematicians.
Penguin Books, 1991.
Sanborn RT: Differences between the facial skeletal patterns of class III
malocclusion and normal occlusion. Angle Orthod 1955; 25:208-22.
Sandler PJ: Reproducibility of cephalometric measurements. Br J
![Page 210: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/210.jpg)
210
Orthod 1988; 15: 105-10.
Sarhan OA, Nashashibi IA: A comparative study between two
randomly selected samples from which to derive standards for craniofacial
measurements. J of Rehab 1988; 15:251-55.
Sarhan OA, Hashim HA: Dento skeletal components of class II
malocclusions for children with normal and retruded mandibles. J Clin
Ped Dent 1994; 18:99-103.
Sassouni V: A roentgenographic cephalometric analysis of cephalo facio
dental relationship. Am J Orthod 1955; 41:735-64.
Sassouni V: A classification of skeletal facial types. Am J Orthod
1969; 50: 109-23.
Savara BS, Tracy WE, Miller PA: Analysis of errors in cephalometric
measurements of three-dimensional distances in the human mandible.
Archs Oral BioI 1966; 11:209-17.
Scheideman GB, Bell WH, Legan HL, Finn RA, Reisch JS:
Cephalometric analysis of dentofacial normals. Am J Orthod
1980; 1 0:68-71.
Schmuth GPF, Chow KW, Drescher D: Comparison of cephalometric
mean values. Bur J Orthod 1988; 10: 68-71.
Sclare R: Orthodontics and the school child: A survey of 680 children.
Br Dent J 1945; 79:278-80.
Seipel CM: Variation of tooth position: a metric study of variation and
adaptation in the deciduous and permanent dentition. Stockholm, Svensk
Tandlakare - Tadskrift, 1946.
Shalhoub SY, Sarhan OA, Shaikh HS: Adult cephalometric norms for
Saudi Arabians with a comparison of values for Saudi and North
American caucasians. Br J Orthod 1987; 14:273-79.
Shaw WC: Orthodonics and occlusal management. W right 1992.
Simon PW: Fundamental principles of a systemic diagnosis of dental
anomalies. Boston, The Stratford Co, 1926.
Slavicek R, Schadlbauer E, Schrangl J: Les rapports squelettiques
et la compensation dento alveolaire, Rev Orthop Dento Faciale
1983; 17:493-516.
Smeets HJL: A roentgenocephalometric study of the skeletal
morphology of class II, Division 2 malocclusion in adult cases.
![Page 211: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/211.jpg)
211
Europ Orthod Soc 1962.
Solow B, Tallgren A: Dentoalveolar morphology III relation to
craniocervical posture. Angle Orthod 1977; 47:157-64.
Solow B: The dentoalveolar compensatory mechanism: Background
and clinical implication. Br J Orthod 1980; 7:145-61.
Stab run AE, Danielsen K: Precision in cephalometric in
cephalometric landmark identification. Eur J Orthod 1982; 4:185-
96.
Stapf WC: A roentgenographic appraisal of the facial pattern in
class III (angle) malocclusion. Angle Orthod 1948; 18:20-27.
Steedle JR, Profflt WR: The pattern and control of eruptive tooth
movement. Am J Orthod 1985; 87:56-66.
Steiner CC: Cephalometric for you and me. Am J Orthod 1953; 39:
729-55.
Stiles KA, Luke JE: The inheritance of malocclusion due to
mandibular prognathism. J Hered 1953; 44:241-45.
Stoeiinga PJW, Leenen RJ: Class II anomalies: A coordinated
approach to the management of skeletal, dental and soft tissue
problems. J Oral Surg 1981; 39:827-41.
Strang R, Thompson W: A textbook of orthodontia, Philadelphia.
Lea and Febiger, 1958; 58.
Swinscow TDV: Statistics at square one. 8th ed, London, British
Medical Association, 1983.
Tanner JM: Foetus into man, physical growth from conception to
maturity. 2nd ed, Castlemead Pub, 1989.
Taylor WH, Hitchcock HP: The Alabama analysis. Am J Orthod
1966; 52:245-65.
Thomas PS, Speidel TM, Isaacson RJ, Worms FW: The role of dental
compensations in the orthodontic treatment of mandibular prognathism.
Angle Orthod 1977; 47:293-99.
Thompson EC, Jurgens EH: Review of surgical procedures for
correction of mandibular prognathism. J Oral Surg 1956; 14:143-200.
Toms AP: Class III malocclusion: a cephalometric study of Saudi
Arabians. Br J Orthod 1989; 16:201-206.
![Page 212: fac.ksu.edu.sa · 2018. 8. 9. · was due to retruded maxilla and relatively normal and/or protruded mandible. The results also revealed that the upper incisors were retroclined and](https://reader036.fdocuments.in/reader036/viewer/2022071416/6112fa6f5d7cc77d295e8413/html5/thumbnails/212.jpg)
212
Turvey TA, Hall DJ, Warren DW: Alterations in nasal airway
resistance following superior repositioning of the maxilla. Am J Orthod
1984; 85: 109-14.
Von Ihering H (1872). Cited in Fiwlay LM: Craniometry and
cephalometry: A history prior to advent of radiography. Angle Orthod
1980; 50:312-21.
Waite DE, Worms FW: Current advances in oral surgery. St. Louis,
CV Mosby Co, 1974.
Walther DP: Some of the causes and effects of malocclusion. Trans Br
Soc Study Orthod 1960; 1-16.
Warren DW: A quantitative technique for assessing nasal airway
impairment. Am J Orthod 1984; 86:306-14.
Watson RM, Warren DW, Fischer ND: Nasal resistance, skeletal
classification and mouth breathing in orthodontic patients. Am J Orthod
1968; 54:367-79.
Williams S, Andreson E: The morphology of the potential class III
skeletal pattern in growing children. Am J Orthod 1986; 55: 302-11.
Worms FW, Isaacson RJ, Speidel TM: Surgical orthodontic treatment
planning profile analysis and mandibular surgery. Angle Orthod 1976; 46:
1-25.
Young HD: Statistical treatment of experimental data. McGraw Hill,
1962.