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Transcript of Diagnostic setup. opg, xeroradiography,clarks technique /certified fixed orthodontic courses by...
Seminar on,
Diagnostic Set upPanoramic Radiography XeroradiographyClark’s technique
INDIAN DENTAL ACADEMY
Leader in continuing dental education www.indiandentalacademy.com
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DIAGNOSTIC SET UP
Practical aid in treatment planning and diagnosis.
Proposed by H.D. Kesling It’s a procedure in which teeth are
removed and replaced in positions they will occupy after experiencing mesial migration in an orthodontic environment.
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Advantages –1. To determine and visualise the resultant
occlusion before the teeth have been extracted
2. Possible to change the treatment plan on the model by replacing some and removing other teeth so that one can thoroughly examine all possible occlusions.
3. Mainly useful in asymmetric extraction and combined surgical orthodontic treatment.
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4. Tooth size – arch length discrepancies can be visualised by means of set up.
5. Also a step in construction of tooth positioner.
6. Patient can be motivated .
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Procedure
A set of well trimmed models made of deep
impressions of teeth and soft tissues.
Lines are drawn through buccal groove on the
mandibular first molars on to the soft tissue.
This act as a reference point.
A . 004 inch ribbon saw blade is used to cut
through the contact areas and separate teeth.
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The lower first permanent molars are replaced to a new position they will occupy by mesial migration.
Deciding lower first molar position is the most important decision in constructing the set up.
Factors influencing position of first molar set up are –
– Size of the teeth– Presence or absence of tooth crowding mesial to anchor
molars.– Procumbency of anterior teeth.– Missing teeth– Age of the patient– Treatment plan– Tooth size related to jaw size.
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After all the above points have been considered, the orthodontist must anticipate the behaviour of anchor molar during treatment.
It again depends on –– Technique employed
– The time requirement
– Orthodontist’s ability
– Patient’s cooperation
At this stage by studying the set up one can analyse that-
If anterior teeth – too far forward – Extraction – If already extracted – more extraction.
If anterior teeth – lingual – Eliminate planned extraction.
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Maxillary teeth are arranged according to mandibular
teeth to obtain best possible occlusion.
In most cases, same no. and type of teeth are removed
from maxillary arch as mandibular arch.
Exception –
– Badly broken down teeth
– Congenitally missing or deformed teeth.
– Single tooth extraction in lower archwww.indiandentalacademy.com
‘A Simplified wax set up technique’ by R.W. Knierim JCO- 1975
According to his procedure – Plaster is filled to about 4 mm over gingival margin of
impression.As the plaster sets rough grooves are made in near set
plaster to depth of 2mm.
When plaster is set it is removed and teeth are numbered.
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Teeth are then separated using discs on a lathe to
slice root area, most teeth will now snap apart.
Root areas are then trimmed.
The impression are saved and kept moist.www.indiandentalacademy.com
The trimmed dies are then reinserted in air dried alginate impression
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Melted wax is then poured in impression holding the dies, it should flow well in grooves.
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Similar grooves are then placed in surface of wax
as it hardens
Plaster is poured over wax surface to make base for model. www.indiandentalacademy.com
‘A simplified Diagnostic set up technique.’ by Dr. Barry N. Resnick; 1979 JCO
According to his procedure –
The plaster is poured in impression only to the extent of
clinical crown.
Soft wax of 5 mm thickness is poured over crown dies.
Remainder of impression is poured with plaster and
allowed to set.
After separation from impression, the model consists of
two plaster section connected by wax.
Teeth are marked and can be repositioned in desired way
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Original study model.
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Alginate impression with selected teeth poured up in stone to the extent of their clinical crowns.
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Dental units and model base connected by periphery wax.
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Diagnostic set up with mandibular left lateral incisor removed and remaining teeth aligned.
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Panoramic Radiography
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Panoramic Radiography
Also called as Ortho pantomograph (OPG)
Rotational Radiography.
It is a radiographic technique for producing
single image of facial structures that includes
both maxillary and mandibular arches and
their supporting structures.
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Advantages-
1. Broad anatomic coverage
2. Simple procedure
3. Better tolerated by pts with gagging problems
4. Low radiation dose
5. Convenience of the examination.
6. Useful in pts who are unable to open their mouth
7. Full mouth IOPA – 15 mins and OPG – 3-4 mins.
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Disadvantages
1. Magnification, Geometric distortion and overlapped images.
2. Resolution of fine anatomic details of peri-apical area and periodontal structures is less.
3. Poor image is obtained when sharp inclination of anterior teeth towards labial or lingual side.
4. The spinal cord superimpose on anterior region.
5. Common to have overlapped teeth images , particularly in premolar area.
6. Artifacts are common and may easily be misinterpreted.
7. Expensive
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Indications
1. To assess pattern and amount of root resorption of deciduous teeth.
2. Useful in mixed dentition period to study the status of unerupted teeth.
3. Presence or absence of permanent teeth: their size, shape, position and relative state of development.
4. To view ankylosed and impacted teeth.
5. To diagnose presence of supernumerary teeth or congenital absence of teeth.
6. To study the character of alveolar bone and immediate lamina dura and periodontal membrane.
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7. To study morphology and angulations of roots of permanent teeth.
8. To study the path of eruption of teeth.
9. To diagnose fractures or pathologies of jaw.
10. To diagnose caries, periapical infections root fractures etc.
11. Useful aid in serial extraction to study status of eruption of teeth.
12. Can assess TMJ and Sinuses.
13. Assess shape, size and symmetry of condyles.
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To interpret OPG competently one must have a thorough understanding of the following :
1. Principles of Panoramic image formation.
2. Techniques for Patient positioning with head alignment and their rationale.
3. Radiographic appearance of normal anatomic structures.
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Principles of Panoramic image formation
First described by Numata and independently by Paatero in late 1940s.
Movement of the film and objects about 2 fixed centers of rotation.
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Movement of film and X- ray source about one fixed center of rotation.
While disc 2 moves, the film on this disc rotates past the slit.
It is critical that speed of the film passing the collimator slit is maintained equal to the speed at which x-ray beam sweeps through the object of interest.
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Movement of the film and x-ray source about the shifting center of rotation.
Structures near the film will be sharply imaged.Structures which are near x-ray source get magnified
and distorted and resultant image is not discrete.www.indiandentalacademy.com
Rotational Panaromic radiographic machines.
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Focal Trough It’s a 3-D curved zone or image layer in which
structures are reasonably well defined on OPG.
The images seen on OPG consists largely of anatomic structures located within the focal trough.
Objects out of focal trough are blurred
magnified/ reduced or distorted.
The shape of focal trough varies
with brands of machines used.
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Ring at center of FT.
Ring 5mm anterior to FT
Ring 5 mm posterior to FT
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Patient positioning and Head alignment.
Prepration of Patients.– Removal of earrings or any other metallic objects in head and
neck region.– Instruct patients to remain still.– Drape with lead apron.
Patient Positioning– Place the pt so that dental arches are located in middle of focal
trough.– A-P positioning – by biting at bite block.– Proper mid sagittal plane –proper head positioning –
cephalostat.– Occlusal plane and chin must be properly positioned – FH plane
parallel with floor..– Back and spine be erect with neck extended.
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If anterior teeth are located behind the FT- Blurred- Wide anterior teeth
If anterior teeth are located infront of the FT-Blurred-Narrow anterior teeth
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If skull tipped too far backward
Position the skull according to FH plane and check for occlusal plane www.indiandentalacademy.com
Correct position using bite block
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If skull tipped too far forward
Position the skull according to FH plane and check for occlusal plane
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Deviation in mid sagittal plane
Asymmetric image
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Positioning of the Tongue
Pt should press tongue against palate
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Radiation dose reduction
By using rare-earth intensifying screens.
Reduce the output by using filters infront of x-ray tube.
Eg. Lanex screens.
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Positioning in mixed dentition stage
•The tooth buds should be in FT
•If additional supernumerary teeth or impacted teeth has to be shown the pt must be positioned with occlusal plane steeply dorsally
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Radiographic appearance of normal Anatomy
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The four Diagnostic regions in OPG
Dentoalveolar region
Maxillary region
Mandibular region
TMJ,including retromaxillary and cervical regionwww.indiandentalacademy.com
Maxillary region
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Mandibular region
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Dentoalveolar region
• Shape and angulation of roots.• Alveolar bone and periodontium• Shows gentle curve of occlusal plane• Missing 3rd molars and• Presence of metallic restorations.www.indiandentalacademy.com
Soft tissue images
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Air spaces
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Xeroradiography
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Xeroradiography
Xeroradiography is the recording of radiologic images by a photoelectric process rather than the photochemical one used in conventional radiography.
An electrostatic image of object is formed on a ‘ Xeroplate’ , a metallic plate coated with Selenium.
An electrostatic image is printed on a paper in such a manner that xeroradiograph is obtained.
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Advantages
Pronounced edge enhancementA choice of positive and negative displayGood detailWide exposure latitudeNo need of silver halide coated films.
Disadvantages
High radiation exposure
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Types of Xeroradiographic systems
Two types –
1. The Medical 125 system– Used since 1970s.– Used manly in Mammography and general
radiography.– Also been used for Cephalometric
radiography and Tomography of TMJ
2. The Dental 110 system Designed for dental Xeroradiographs
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Medical Xeroradiography
Conventional X-ray source is needed.
Image is recorded on Selenium coated plate.
Before use, Selenium photoreceptors which are
stored in a unit called conditioner are given a
uniform electrostatic charge
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Processing of Xeroplate before exposure
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Exposure of Xeroplate
Latent image
Latent image is converted to visible image by process called Development, in unit called Processor
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Development of Image
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Positive ImageDarkest areas corresponds to most dense parts of anatomy.
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Darkest areas corresponds to least dense parts of anatomy and dense objects appear white.
Negative image
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Dental Xeroradiography
Dental 110 xeroradiogrphic unit system is similar to medical 125 system in concept but its design is physically different.
The image receptor plates are the size no. 1 and no. 2 films and fit well in oral cavity.
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Dental xeroradiographic processor.
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Dental Xeroradiographic procedure.
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Radiologic exposure conditions and resultant skin doses in application of Xeroradiography to Orthodontic diagnosis. AJO-DO, 1980 by Akihiko Nakasima (Japan )
Minimum xeroradiologic exposure conditions for Skull projections, Schuller’s and TMJ projections and Hand projections were established by 13 examiners.
Relation b/w image production and radiation dose was discussed in comparison with conventional film techniques.
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The advantages were-
– finer and clearer images due to edge effect and wider latitude.
– Landmarks on cephlaogram such as Sella, ANS,Basion, etc were more clear and exactly set.
– Outline of condylar process and articular fossa, the trabecular pattern of mandible and interdental crestal bone edges were more clear and distinct.
The main hazard was unavoidable larger skin radiation dose . It was 2.4 to 16.2 times larger than conventional film techniques.
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A cephalometric appraisal of Xeroradiographyby Chate – AJO-DO 1980
Aim : To estimate the effect of xeroradiographic technique on the degree of inter and intra observer error in cephalometric landmarks identification.
Method
This study involved identification by four observers of 16 cephalometric landmarks on 12 xeroradiographs & on 12 radiographs, on 2 separate occasions.
Conclusion Neither technique provided a significant decrease in interobserver
differences. However, for 8 of 32 variables, xeroradiography produced a
significant reduction in intraobserver error in comparison to radiography.
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Clark’s technique
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Localization technique
Two methods are used in dentistry to obtain 3-D information –
1. To employ two films projected at right angle to
each other.
2. Tube shift/cone shift principle or Clark’s technique or buccal object rule or SLOB rule.
Mainly used in Orthodontia to locate position of
impacted canine.www.indiandentalacademy.com
Clark’s technique
C.A Clark described it in 1910.
Its based on Parallax principle.
In this , 2 periapical films are taken, – First, standard orthoradial projection,
– Second, employs a vertical or horizontal change in central ray projection.
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The apparent movement of the object in this radiograph will provide clue to its exact location.
According to rule of thumb objects which moves with central ray movement are actually behind the reference object.
Its basis of SLOB rule, that is Same side Lingual Opposite side Buccal
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Horizontal shift of central ray
Distal shift of cone
StandardCone shift
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Vertical shift of central ray
Standard Vertical shift
Standard Vertical shift
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INDICES
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Index
According to Russell, an index is defined as
‘A numerical value describing the relative status of the population on a graduated scale with definite upper and lower limits which is designed to permit and facilitate comparison with other population classified with the same criteria and the method.’
In the orthodontic context index is described as –
‘A rating or categorizing system that assigns a numeric score or alpha numeric label to a person’s occlusion.’
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Requirements of ideal orthodontic index are –
(Jamison H.D. and Mc Millan R.S )
1. Simple, reliable and reproducible.
2. Objective and yield quantitative data.
3. Differentiate b/w handicapping and non handicapping malocclusions.
4. Measure degree of handicap.
5. Quick examination.
6. Amenable to modifications.
7. Usable either on patient or on study model.
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Types of Indices ( according to WHO)
Occlusal Classification
– Angle’s classification by Angle in 1899
– Incisor classification by Ballard and Wayman, 1964
Skeletal classification by Houston et al, 1993
Malocclusion
– Occlusal index by Summers 1966
– Handicapping Malocclusion Assessment Record (HMAR) by Salzmann, 1968
– Index of Treatment Need by Evans and Shaw 1987
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Treatment assessment
– Little’s irregularity index by Little 1975
– Peer Assessment rating by Richmond et al, 1992
Cleft Outcome
– Goslon Yardstick by Mars et al, 1987
– 5Year olds’ Index by Atack et al ,1997
Periodontal
– Plaque Index by Stilness & Loe , 1964
– Gingival Index. by Loe & Stilness, 1963
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Types Of Indices According to Shaw , Richmond and O’Brien
Diagnostic Classification– Angle’s classification– Incisor classification
Epidemiologic indices
– Study prevalence of malocclusion in population.– Eg 1.Summer’s occlusal index. 2. Registration of malocclusion described by
Bjork, Krebs and Solow
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Treatment need ( Treatment priority) indices.– Categorize malocclusion according to levels of treatment
needs.– Eg 1. Index Of Treatment Need (IOTN) 2. Draker’s Handicapping Labio – Lingual Deviation
index (HLD) 3. Grainger’s Treatment Priority Index.(TPI) 4. Salzmann’s Handicapping Malocclusion Index
Treatment outcome indices.– Assesssment of changes resulting from treatment– Eg 1. Peer Assessment Rating index 2. Summer’s index
Treatment complexity index– Index of Complexity Outcome and Need (ICON)
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Various indices of Occlusion
Master and Frankel (1951)– Count the number of teeth displaced or
rotated– Qualitative assessment
Malalignment Index byVankrik and Pennel (1959)– Tooth displacement and rotations were
measured.
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Handicapping Labio – Lingual deviation index
Proposed to select subjects with severe or handicapping malocclusions and dentofacial anomalies.
Applicable only to permanent dentition
First Orthodontic index to meet administrative needs of programme planners.
Made use of weighting factors developed by trial and error.
Had 9 components
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Conditions observed HLD score1. Cleft palate Score 152. Severe Traumatic deviations Score 153. Overjet in mm4. Overbite in mm5. Mandibular protrusion in mm x 5 6. Open bite in mm x 47. Ectopic eruption ,Anteriors only x 38. Anterior crowding : Maxilla9. Anterior crowding : Mandible
TOTAL
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Handicapping Labio – Lingual deviation index by Draker (1960)
Modification of earlier used HLD index
Main aim is to find presence or absence and degree of handicap caused by components of index.
Has 7 components.
All measurements are made with Boley gauge scaled in mm.
A score of 13 and over constitutes physical handicap
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7 conditions of HLD index are -
1. Cleft palate2. Traumatic deviations3. Overjet4. Overbite5. Mandibular protrusion6. Open bite7. Labio Lingual spread
Following codes are used – ‘O’ = condition present ‘X’ = condition absent ‘M’= mixed dentition ‘A’= Clinical approval ‘D’=Clinical disapprovalwww.indiandentalacademy.com
Occlusal index by Summers (1966)
Used to assess severity of malocclusion in population
Nine weighted and defined measurements –
1. Molar relation2. Over jet3. Overbite4. Posterior cross bite5. Posterior open bite6. Tooth displacement7. Midline relation8. Maxillary median diastema9. Congenitally missing maxillary incisors.
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Seven malocclusion syndromes defined
1. Overjet and open bite2. Distal molar relation, overjet, overbite, posterior
crossbite, midline diastema and mid line deviation.3. Congenitally missing maxillary incisors.4. Tooth displacement. 5. Posterior open bite.6. Mesial molar relation, overjet, overbite, posterior
crossbite, midline diastema and mid line deviation.7. Mesial molar relation, mixed dentition analysis
(potential tooth displacement) and tooth displacement.
Different scoring schemes and forms for different stages of dental development: Deciduous, Mixed & Permanent dentition.
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Treatment priority index by Grainger (1967)
The precursor of the TPI was the Malocclusion Severity Estimate (MSE) developed by Grainger at the Burlington Orthodontic Research Center in 1960-61
Unlike the TPI, the MSE score was that of the syndrome with the largest value, regardless of the scores of the other syndromes.
The TPI also differed from the MSE by deleting potential tooth displacement (mixed-dentition space analysis) and by rating distoclusion and mesioclusion equally.
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Treatment priority index by Grainger (1967)
11 weighted and defined measurements –1. Upper anterior segment overjet.2. Lower anterior segment overjet.3. Overbite4. Anterior openbite.5. Congenital absence of incisors.6. Distal molar relation7. Mesial molar relation8. Posterior cross bite (max. teeth buccal to normal).
9. Posterior cross bite (max. teeth lingual to normal).
10. Tooth displacement11. Gross anomalies.
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Seven malocclusion syndromes were defined -
1. Prognathism
2. Retrognathism
3. Overbite
4. Openbite
5. Maxillary expansion syndrome
6. Maxillary collapse syndrome
7. Congenitally missing incisors
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TPI is based on a scale of
1. 0 (near ideal occlusion)
2. 1 - 3 ( mild malocclusion)
3. 4 – 6 ( Moderate malocclusion)
4. Over 6 ( severe malocclusion)
TPI scores only occlusal characteristics, excluding skeletal and facial components.
TPI is used in national studies of orthodontic needs for children. Eg. USPHS study in USA of childeren aged b/w 6-11 yrs in year 1967
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Handicapping malocclusion assessment records by Salzmann (1968)
The purpose of HMAR – To establish priority for treatment according to severity as shown by score.
Weighted measurements consists of 3 parts –1. Intra arch deviations
Missing teeth Crowding Rotation Spacing
2. Interarch deviations Overjet Overbite Crossbite Openbite Mesiodistal deviationswww.indiandentalacademy.com
3. Six handicapping dento-facial deformities
1. Facial and oral clefts
2. Lower lip palatal to maxillary incisors.
3. Occlusal interferences
4. Functional jaw limitations
5. Facial asymmetry
6. Speech impairment.
Score 8 points for each deviation.
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Instruction for Scoring
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Peer assessment rating Index (PAR index)Index of orthodontic treatment outcome
Developed by 10 experienced British orthodontists.
Its developed mainly to assess effectiveness of
Orthodontic treatment .
Assigns scores to different occlusal traits.
Study models used.
A scoring system was developed and a ruler designed
to allow analysis of a set of study casts in 2 minutes.
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5 components- Weighting
1. Upper & lower anterior segment - 1
2. Left and right buccal segments - 1
3. Over jet - 6
4. Overbite - 2
5. Centerlines - 4 Individual scores are summed to get a final score.. Index is applied to both the start and end of treatment
study casts, and change in total score reflects the success of treatment.
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Change expressed as:1. Reduction in weighted PAR score : 22 point reduction –
Greatly improved2. % reduction in weighted PAR score: < 30% reduction – worse/ no better > 30% reduction – Improved. Indicator of clinical performance.
Limitations of PAR1. Generic weightings of Over jet and overbite.2. Sensitive to malocclusion with high over jet.3. Overbite low weighting.4. Zero weighting for displacements.5. Facial profiles not considered Eg. Bimaxillary
protrusion
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TheValidation of PAR for Malocclusion severity and Treatment DifficultyDe Guzman,bahiraei, Vig, Weyant and O’Brien – AJO-DO 1995
11 American Orthodontists examined a sample of 200 sets of study casts and rated them for malocclusion severity and perceived treatment difficulty.
The results of this study made it possible to derive a set of weightings for the PAR index that would represent groupings of malocclusion severity and treatment difficulty, according to perceptions of panel of Orthodontists.
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Index of Treatment Need (IOTN)
by Shaw
Index has two components-
1. Dental Health component – derived from occlusion and alignment.
2. Aesthetic component – Derived from comparison of dental appearance to standard photographs.
Aesthetic component is calculated by direct examination, but dental health component can be studied by dental casts.
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A special ruler summarizes the information needed for dental health component.
Assessed in order :
1. Missing teeth
2. Overjet
3. Crossbites
4. Displacements (Contact point)
5. Overbite
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Esthetic Index
Grades 8 – 10 = definite need for treatment.
5 – 7 = moderate/ borderline need
1 – 4 = No/ slight need
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Limitations
1. In aesthetic component ,Class III not considered.
2. Facial profile not considered.
3. Class I bimaxillary protrusion not considered.
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Index of Complexity Outcome and Need (ICON)
Based on expert opinions of 97 orthodontists from various countries.
For use on patients and Dental casts.
A single assessment method to record complexity, outcome and need.
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5 components taking about 1 min to measure.
1. Aesthetic component 10 pictures
2. Upper arch Crowding/ Spacing Score according to amount of crowding or spacing Impacted teeth in either arch immediately scored 5 Spacing in one part can cancel out crowding elsewhere.
3. Crossbite4. Incisor open bite/ overbite
Open bite measured at mid incisal edges Deep bite is measured at deepest part of overbite.
5. Buccal segment Antero posterior Quality of buccal segment interdigitation is measured
(not Angles Classification)
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1. Aesthetic component
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ICON Scoring Method
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Limitations
1. Overjet not considered.
2. Lower anterior crowding not considered.
3. Midline shift not taken in account.
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The purpose of this study was to develop a valid and reliable index that provides relatively objective judgments of dental-facial attractiveness.
The subjects in this study were eighth- and ninth-grade children. Few were seeking orthodontic treatment and few were not seeking treatment.
Photographs of the children were rated for dental-facial attractiveness by lay and dental judges.
A dental-facial attractiveness scale Tedesco, Albino, Cunat AJO-DO 1983
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Standard photographs of white males for points 1 (most attractive) through 5 (least attractive) on the dental-facial attractiveness scale.
Point 1 Point 2
Point 3 Point 4 Point 5
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Children were also assessed for severity of malocclusion by means of the Treatment Priority Index
Children seeking treatment were perceived as significantly less attractive than children not seeking treatment.
The relationship between dental-facial attractiveness and overall severity of malocclusion is also established as proved by TPI scores.
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Goslon yardstick :A new system of assessing dental arch relationships in childeren with UCLP – Michael Mars, Dennis A. Plint : 1987 A cleft Palate journal
The Goslon Yardstick is a clinical tool that allows categorization of the dental relationships in the late mixed and or early permanent dentition in to 5 discrete categories.
Objective : 1. To categorize malocclusions in patients with UCLP to represent severity of malocclusion and the difficulty of correcting it.
2. To compare long term results of different approaches to the early treatment of children with UCLP.
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Development of Yardstick – Clinical features considered most important in characterizing malocclusion in children with UCLP are –
1. A- P arch relationship –Class III incisor relationship> class II div I
2. Vertical labial segment relationship – Open bite> Reduced overbite > deep overbite.
3. Transverse relationship – Canine crossbites > molar crossbites.
To test the application of these subjective criteria study models of 30 cases were taken.
These models were ranked by 4 orthodontists and separated in 5 groups , which then formed basis for yardstick.
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Group 1 – excellent Group 2 – good Group 3 – fair Group 4 – poor Group 5 – very poor
Group 1 or 2 - simple orthodontic treatment/ no treatment
Group 3 – complex orthodontic treatmentGroup 4 – limit of orthodontic treatment without
orthognathic surgeryGroup 5 – Orthognathic surgery
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References (Diagnostic set up)
1. Begg Orthodontics Theory & Technique – Kesling
2. Diagnosis and treatment planning
in Orthodontics – Van der Linden
3. A Simplified wax set up technique by Dr. R.W. Knierim JCO-1975.
4. A simplified Diagnostic set up technique by Dr. Barry N. Resnick; 1979 JCO.
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References (Radiology)
1. Oral radiology – Goaz & White.
2. A Colour Atlas of Dental Radiology – Friedrich A Pasler.
3. Essentials of Dental Radiography – Orien N Johnson.
4. Principles of Dental Imaging – Langland.
5. Orthodontics - T. M .Graber.
6. Radiologic exposure conditions and resultant skin doses in application of xeroradiography to Orthodontic diagnosis by Akihiko Nakasima AJO-DO, 1980 .
7. A cephalometric appraisal of Xeroradiographyby Chate AJO-DO 1980.
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References ( indices)
1. Contemporary Orthodontics – Proffit
2. M Ortho Journal – Bristol University
3. Longitudinal evaluation of the Treatment Priority Index (TPI) AJO-DO 1989
4. Goslon yardstick:A new system of assessing dental arch relationships in childeren with UCLP – Michael Mars, Dennis A. Plint : 1987 A cleft Palate journal
5. A dental-facial attractiveness scale Tedesco , Albino, Cunate AJO-DO 1983
6. The Development of PAR Index – S. Richmond
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7. Handicapping Malocclusion assessment to establish treatment Priority J A Salzmann – AJO –1964
8. The use of Occlusal Indices : A European prospective – AJO-DO 1995
9. The validation of PAR for malocclusion severity and treatment difficulty AJO-DO 1995
10. The effectiveness of ClassII div I treatment – AJO-DO 1995
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