Correction of extreme overjet in 2 phases

CASE REPORT

Correction of extreme overjet in 2 phasesLouise Wong,a Urban Hägg,b and George Wongc

Hong Kong SAR, China

This case report describes the treatment of a 12-year-old Chinese boy with a Class II skeletal profile, anextreme overjet, and a retrusive mandible. The patient was teased at school because of his appearance, andhe was experiencing negative psychosocial impacts, including shyness and falling grades. Orthodontictreatment had a positive psychosocial impact on his life over a period of 10 years. The advantages of using
functional appliances are highlighted in this report. (Am J Orthod Dentofacial Orthop 2006;130:540-8)
The etiology of a Class II malocclusion oftendetermines the most suitable treatment option.The treatment options for a Class II patient with

severe overjet might include conventional orthodonticswith extractions, orthognathic surgery combined withorthodontic treatment, or functional appliance therapywith orthodontics. In the Third National Health andNutrition Examination Survey (NHANES III), 0.2% of8- to 11-year-old children had overjets greater than 10mm, compared with 45% who had overjets of 3 to 4mm.1 Therefore, although extreme overjet appears to berelatively uncommon, quality of life can be severelyaffected for those who do have it.2,3 A dentofacialdeformity such as a severe Class II malocclusion can bea psychosocial stigma.4 The stereotypical typecastingof people based on their dental features can be seen ontelevision and in cartoons. A character with a Class IIDivision 1 malocclusion is often portrayed as goofy orstupid. Studies have shown that children with abnormaldental features (such as severe overjet) are more likely tohave nicknames and experience harassment and teasingfrom their peers.5-7 Early correction of the malocclusioncould have a psychosocial benefit for the child during theformative years of life, when social acceptance by peersplays a critical role in self-esteem.8 Certainly, recentstudies have indicated that early treatment for Class IIpatients can increase a child’s self-concept and reducenegative social experiences.9 Furthermore, children withlarge overjets have a greater risk of injury to their anterior

aAdvanced student in orthodontics, Faculty of Dentistry, University of HongKong, Hong Kong SAR, China.bProfessor and associate dean, Postgraduate and Continuing Education, Facultyof Dentistry, University of Hong Kong, Hong Kong SAR, China.cPrivate practice, Hong Kong SAR, China.Reprint requests to: Urban Hägg, Orthodontics, Faculty of Dentistry, Univer-sity of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Rd, Hong KongSAR, China; e-mail, [email protected], August 2004; revised and accepted, June 2005.0889-5406/$32.00Copyright © 2006 by the American Association of Orthodontists.
doi:10.1016/j.ajodo.2005.06.019
540

teeth, although recent studies have indicated that theextent of the trauma might be minor.1,10,11

This case report describes the treatment of a childwith a severe Class II malocclusion, and it highlightsthe psychosocial, psychological, and functional benefitsof treatment.

DIAGNOSIS AND ETIOLOGY

The patient, a Chinese boy, 12.5 years of age,sought orthodontic treatment in 1991. He said that hisupper teeth stuck out, and he was constantly teased byhis classmates. His parents noticed a change in hisbehavior shortly after he entered secondary school, andthey were worried that his dental abnormality wasmaking him more withdrawn and shy. After enteringsecondary school, his grades had dropped.

The clinical examination showed a symmetricalface, incompetent lips with a short upper lip, an acutenasolabial angle, a convex lateral profile, and a flatchin. The lower facial height was smaller than normal,and the lower lip was trapped behind the maxillaryincisors. The upper lip was full and everted. Markedactivity of the mentalis muscle was noted on swallow-ing.

Analysis of the study models showed a Class IIDivision 1 malocclusion with an overjet of 17 mm anda traumatic overbite of 100%. Palatal indentations werepresent in the maxillary arch due to the traumatic bite.Tooth 55 (FDI tooth number) was exfoliating, and 15was erupting. There were spacing and dental irregular-ity in both arches. The maxillary incisors were pro-clined with 6 mm spacing in the anterior segment. Themandibular arch was parabolic in shape, with 3 mmspacing and a deep curve of Spee. Both upper andlower midlines coincided with the facial midline. Thecanines and the molars were in a full unit Class II withscissors-bite at 24/33 and 25/34.

Radiographic analysis of the lateral cephalogramshowed a skeletal Class II relationship (ANB angle,
6.5°) due to a retrognathic mandible (SNB angle, 74°).

American Journal of Orthodontics and Dentofacial OrthopedicsVolume 130, Number 4

Wong, Hägg, and Wong 541

The maxillary incisors were significantly proclined,(UI/MxPl, 125.9°) compared with the Chinese norm(118°), and the maxillomandibular plane was reduced(17.7°), with the maxillary incisors lying well ahead ofthe esthetic line.12 The lower facial height was reducedat 52%. The panoramic radiograph showed no abnor-mality, and all permanent teeth were present, with thethird molars at crown-formation stage.

Maturity status assessment showed a pubertalvoice, and a hand-wrist radiograph indicated that thepatient was close to his pubertal maximum of facialgrowth (stage MP3-FG).13

The orthodontic diagnosis was Class II Division 1malocclusion on a skeletal II base with increasedoverjet and lip incompetence. The mandible was ret-rognathic, and the maxillary incisors were proclined.An increased and traumatic overbite was present, lead-ing to a deep curve of Spee. Both treatment need andtreatment demand were high.14

TREATMENT OBJECTIVES

1. Improve the sagittal skeletal relationship betweenthe maxilla and the mandible.

2. Reduce the overjet and eliminate the traumaticoverbite.

3. Eliminate the scissors-bite.4. Align and harmonize the arches.5. Improve lip competency.

TREATMENT ALTERNATIVES

Three treatment options were identified. In option 1,treatment would be conducted in 2 phases and includefunctional appliances, with or without extractions. Inoption 2, orthodontic treatment would be combinedwith orthognathic surgery. Option 3 consisted of cam-ouflage treatment with extraction of 14 and 24, andpossible extraction of 35 and 45.

Option 1 was selected because it was the best wayto increase mandibular length and improve the facialprofile. The goal in the initial phase of treatment was torestrain maxillary growth and guide the mandible into amore favorable forward position; in phase 2, the teethcould be aligned and the arches harmonized.

TREATMENT

Phase 1 treatment began with a banded Herbstappliance advanced in a stepwise fashion. The bite wastaken with the mandibular incisors initially posturedforward 7 mm. Because of spacing in the arches, allanterior teeth were bonded at the same visit as theHerbst cementation with .022 � .028-in Roth prescrip-
tion brackets. A sectional 016-in nickel-titanium wire
was used to align the teeth, and the spaces wereconsolidated by using an .018-in stainless steel wirewith continuous power chain. The telescopic arms wereadvanced after 3 months to achieve an incisal edge-to-edge bite. Active Herbst treatment continued for 8months, during which time the Class II relationship wasovercorrected to a Class III relationship, the overjet waschanged by nearly 2 cm into a reverse overjet, and thetraumatic bite was eliminated. Two emergency visitswere required during phase 1 because of breakages ofthe functional appliance; this problem is more prevalentin banded Herbst appliances than in their splintedcounterparts.15

A Van Beek activator was placed after removal ofthe Herbst appliance to allow for settling of the buccalocclusion and uprighting of the mandibular incisors.16,17

The patient was observed for 5 months to evaluate post-treatment changes. At the end of the observation period,the incisal relationship became edge-to-edge.

Phase 2 consisted of fixed appliance treatment.The Begg light-wire technique was used for 12months to align and harmonize the arches. First, a.016-in Australian stainless steel wire was placed,and light Class II elastics were used to improve theposterior open bite. Two months later, .018-in Aus-tralian stainless steel wire and Class I elastics wasplaced for space closure. Finally, rotational anduprighting springs were added to align the teeth.Both maxillary and mandibular incisal inclinationswere uprighted with torquing accessories. Final fin-ishing wires (blue Elgiloy .019 � .025-in [RockyMountain Orthodontics, Denver, Colo}) were placedto detail the final tooth position.

The patient was given a maxillary Begg retainerand instructed to wear it 24 hours a day for the first12 months and at night thereafter. An anterior biteplate was incorporated to compensate for the strongdeepbite tendency. A mandibular bonded lingualretainer using .0175-in twistflex wire was bondedfrom canine to canine. After 2 years of retention, thepatient was discharged from the department. Tenyears after removal of all appliances, the patient wasrecalled, and records were taken. He was also inter-viewed about his orthodontic treatment and qualityof life.

TREATMENT RESULTS

During treatment, the patient’s profile quicklychanged from convex to straight, which allowed for lipcompetency (Fig 1). The sagittal relationship betweenthe maxilla and the mandible improved from an ANBangle of 6.6° to 1.6° (Table I, Fig 2). The fullness of the
lips and the nasiolabial angle were reduced after incisor

ar

tment;

American Journal of Orthodontics and Dentofacial OrthopedicsOctober 2006

542 Wong, Hägg, and Wong

retraction, and there was significant forward growth ofthe mandible, leading to a marked improvement in thelip-to-esthetic line relationship.

The dental changes, evident by comparing thepretreatment and posttreatment dental casts (Fig 3,A-J), were dramatic. The Class II relationship wascorrected to Class I, overjet was reduced from 17 to2 mm, and the traumatic overbite was normalized,from 100% deep and complete, to 20%. Overjetcorrection was largely due to a combination ofstimulated forward mandible growth and retraction

Fig 1. Lateral profile photographs: A, pretreatmsecond mandibular advancement; D, posttrea

of the maxillary incisors (Fig 4). The overjet correc-

tion after removal of the fixed appliances was a resultof skeletal and dental effects (47% and 53%, respec-tively), whereas the molar correction was largelyaccomplished by the skeletal component (70%).Favorable mandibular vertical growth and dentoal-veolar development contributed to the overbite cor-rection and the leveling of the deep curve of Spee(Figs 4 and 5). As treatment proclined the mandibulincisors, a bonded lingual retainer was placed. Totaltreatment time was 25 months (8 months for phase 1,5 months for a settling period, and 12 months for

, after initial mandibular advancement; C, afterE, 10 years posttreatment.

ent; B

phase 2).

entric



FOLLOW-UP

Full records were collected at the 10-year follow-up. Cephalometric values (Table I) indicated that themarked improvement in the sagittal jaw relationshipachieved during orthodontic treatment was maintained10 years after removal of the appliance. The profile wasstill straight, and the lips were still competent (Fig 1, E).However, a small relapse in the incisors was noted,

Table I. The patient’s dentofacial characteristics and ch

Variable

NormalPretreatment

T0 (SD)Posttre

T1 (Mean SD

SNA angle (°) 82 3.5 80.6 (�0.4) 79.7 (SNB angle (°) 79 3.0 74.0 (�1.6) 78.0 (ANB angle (°) 3.0 2.0 6.6 (1.8) 1.6 (Wits appraisal (mm) �4.5 3.0 7.3 (0.9) �1.7 (UI/MxPl (°) 118 6 125.9 (1.3) 115.0 (LI/MnPl (°) 97 7 102.4 (0.8) 113.8 (MM angle (°) 26 5 17.7 (�1.9) 18.3 (LI/Apo (mm) 5.5 2.5 0.0 (�2.0) 7.0 (Upper lip to E (mm) 3.0 7.4 1.Lower lip to E (mm) 4.0 0.8 4.

Source of normal values for Chinese: Cooke and Wei.12

Fig 2. Superimposed cephalometric tracings: Asuperimposed along S-N plane; B, posttreatmC, pretreatment and 10 years posttreatment c

with proclination of the maxillary incisors, a median

diastema, and retroclination of the mandibular incisorsleading to an increase in overjet from the originalposttreatment value of 2 to 4 mm (Fig 3, K-O). Thepatient lost both retainers soon after treatment. Anupper midline shift was present, and there was mildincisor irregularity in the mandibular arch. Both ca-nines and molars were in a solid Class I relationship.

Although mild dental relapse had occurred, the

during the observation

10 y posttreatmentT2 (SD)

DifferenceT1-T0

DifferenceT2-T1

DifferenceT2-T0

81.0 (�0.3) �0.9 �1.3 0.479.8 (0.3) 4.1 �1.8 5.81.2 (�0.9) �5.0 �0.4 �5.4

�1.0 (1.2) �9.1 �0.7 �8.3120.8 (0.5) �10.9 5.8 �5.1110.1 (1.1) 11.4 �3.7 7.715.4 (2.1) 0.5 �2.9 �2.35.2 (0.1) 6.9 �1.8 5.1

�1.8 �5.8 �3.5 �9.20.9 3.5 �5.2 0.1

treatment and posttreatment centric occlusiond 10 years posttreatment centric occlusions;occlusions.

anges

atmentSD)

�0.7)�0.3)�0.7)2.1)�0.5)2.4)�1.5)0.6)73

, preent an

patient was still greatly satisfied with his teeth. He was

0 yea



training to become an electrician and was in a steadyrelationship. When asked what impact, if any, the 2years of orthodontic treatment had on his life, he

Fig 3. Dental casts: A-E, pretreatment; F-J, 4

Fig 4. Superimposed tracings, with maxillarysuperimposed on mandibular symphysis: A, pr10 years posttreatment; C, pretreatment and 1

recalled that, on entering primary school, he never took

much notice of his teeth, and his close friends nevermade an issue of his dentofacial appearance. However,the teasing and bullying began when he started second-

posttreatment; K-O, 10 years posttreatment.

and inner contour of cortical plate of boneent and posttreatment; B, posttreatment and

rs posttreatment.

years

planeetreatm

ary school, which was in a different district. He began



Fig 5. Pancherz analysis: A, pretreatment and immediate posttreatment; B, pretreatment and
10 years posttreatment; C, posttreatment changes.



to take sick leave regularly to avoid the taunts, and hisschool work lagged behind his peers. At school, he wasmade vividly conscious that his appearance was abnor-mal, so he made little effort to make new friends. Hebegan to have suicidal thoughts, which he confessed tohis parents in a fit of temper when they refused tobelieve that he was ill. Surprisingly, during activeorthodontic treatment, none of his classmates com-mented or teased him about his braces, and the bullyinggradually lessened. When active treatment was fin-ished, several classmates commented on how muchbetter he looked.

DISCUSSION

Tweed18 once said “The world should be a beautifulplace for a child to live in. If he is handicapped byfacial deformity that is marring his happiness, weshould make every effort to restore that happiness.” Intoday’s society, attractive people are perceived to bemore intelligent, better adjusted, and more popular.19

Psychologists call this the “halo effect,” because of theperfection associated with angels.20 Whether this is trueappears to be irrelevant to the people who seek plasticsurgery, and the industry and media that spend billionsof dollars feeding the myth.

In children with Class II malocclusions, mandibularretrusion was found to be the most common singledentofacial feature.21,22 Ethnic variations have alsobeen reported in southern Chinese patients with Class IIDivision 1 malocclusions exhibiting more prognathicmaxillae, less retrusive mandibles, flatter chins, steepermandible plane angles, and more proclined maxillaryincisors than white people.23

Having no active treatment could be 1 alternative,but recent studies have shown that improvement fromgrowth alone is unpredictable. In a sample of untreatedClass II patients, growth was found to be unfavorable in15% and very favorable or favorable in 35%, leavingmost—50%—the same.24 Other prospective studieshave shown favorable improvement in the jaw-baserelationship in their samples (24% and 31%), althoughmany patients (44% and 24%) had worsening of theirskeletal relationships with time.25,26 Nevertheless, theclinical significance of overjet reduction in skeletalClass II subjects by growth alone appears modest atbest.27,28 One study reported that, in a group of un-treated skeletal Class II subjects, overjet change fromage 12 to adulthood was, on average, about 1 mm, withindividual variations from improvement to worsen-ing.27 Therefore, the possibility of significant estheticimprovement in an untreated child with a severe skel-etal Class II pattern appears clinically small.

Orthodontic camouflage for patients with severe

dentofacial deformities could be an option, but obtain-ing good buccal occlusion at the expense of thepatient’s profile is unacceptable.1 For patients withmandibular deficiency, successful reports of early sur-gery (before growth was completed) have been docu-mented.29 A comparison in the long-term follow-up ofpatients treated with orthodontic camouflage rather thansurgical correction of Class II malocclusion showedthat, overall, both groups were satisfied with theirtreatments, but the surgery patients had more positivefeedback on their dentofacial images after surgicalmandibular advancement.30 However, as with everyinvasive procedure, certain risks are involved, andpostoperative complications after orthognathic surgeryhave been well documented.31,32 Johnston reported that10% of patients ultimately experienced total condylarresorption after orthognathic surgery.33 However, pa-tients treated with orthodontic camouflage reported lessfunctional temporomandibular joints or temporoman-dibular joint problems than did surgery patients.30

For severe Class II malocclusions, orthopedic ap-pliances could be used to correct the malocclusion andimprove facial esthetics without the need for invasivesurgery and its associated risks. The defining limitbetween modifying facial growth through orthopedicappliances or by surgical intervention to correct severeClass II malocclusions has never been clear. No definiteguidelines exist on which approach is more appropriate;although some have suggested that correcting a 15-mmoverjet would be more feasible with orthognathic sur-gery.1 Clinical studies have reported significant im-provements in the jaw-base relationship after functionalappliance therapy.28,34 Studies have shown that ortho-pedic appliances that advance the mandible in a step-wise fashion appear to have a greater effect on thesagittal jaw relationship than 1-step advancement.35,36

Magnetic resonance imaging studies in humans and ex-perimental studies on rats have shown that incrementaladvancement of the mandible culminated in increasedremodeling at the temporomandibular joint,34,37,38 whichwas enhanced by using headgear in addition to the Herbstappliance.35,36

Values derived from the Burlington OrthodonticResearch Centre for 12-year-olds indicated that thispatient had a normal midfacial length but a reducedmandibular length (Table II). However, at age 14, afterfunctional appliance therapy and orthodontic treatment,mandibular length was significantly increased (120.4mm) and equal to that of untreated normal 14-year-oldswith good skeletal balance.39 Furthermore, accordingto the longitudinal studies of the Bolton standards and
the Burlington sample,39 the geometric relationship be-



tween effective midfacial length and effective mandibularlength was normalized after treatment (Table II).

Although randomized clinical trails to date areinconclusive as to the extent of mandibular growth, allstudies agree that an early phase of orthopedic treat-ment substantially reduces overjet in children withClass II malocclusions.24,40,41 The real debate lies inthe cost-effectiveness of implementing a 2-phase treat-ment regimen in which an orthopedic appliance is firstused to change the skeletodental relationships, followedby fixed appliances to align the malposed teeth. AUniversity of North Carolina study reported that earlyfunctional appliance treatment did not, on average,influence the Class II skeletal pattern to a clinicallysignificant degree and questioned the benefit of func-tional appliances in terms of time and cost to thepatient.24 On the other hand, the psychological benefitof early treatment to the child cannot be disputed,especially when the overjet is so extreme that it leads toa dentofacial deformity. Cost cannot always be judgedby monetary value alone, and, undoubtedly for thispatient, the cost of delayed orthodontic treatment wouldhave been great.

REFERENCES

1. Proffit WR. Contemporary orthodontics. 3rd ed. St Louis: C. V.Mosby; 2000.

2. Lindsey S. A guide to purchasers of clinical psychology services.Briefing paper no.11: clinical psychology in dentistry. LeicesterUK: British Psychological Society; 1996.

3. Dibiase AT, Sandler PJ. Malocclusion, orthodontics and bully-ing. Dent Update 2001;28:464-6.

4. Helm S, Kreiborg S, Solow B. Psychosocial implications ofmalocclusion: a 15-year follow-up study in 30-year-old Danes.Am J Orthod 1985;87:110-8.

5. Shaw WC, Meek S, Jones D. Nicknames, teasing, harassmentand the salience of dental features among school children. Br JOrthod 1980;7:75-80.

6. Macgregor FC. Social and psychological implications of dento-facial disfigurement. Angle Orthod 1970;40:231-3.

7. Lansdown R, Lloyd J, Hunter J. Facial deformity in childhood:severity and psychological adjustment. Child Care Health Dev

Table II. The patient’s dentofacial characteristics obtainthe norms

VariablePretreatment(age, 12 y)

Norm* for age12 y

Mean SD

Mandibular length (Co-Gn) 109.1 113.0 5.11Midface length (Co-Point A) 90.8 90.3 3.6Maxillomandibular differential 18.3 22.7Lower anterior facial height 66.8 63.4 4.7

*Source of normal values, McNamara.39

†Ann Arbor sample.42

1991;17:165-71.

8. Albino JE. Effects of orthodontics on psychosocial functioning(Final Report: Contract No. R01-DE-06154). Bethesda, Md:National Institute of Dental Research; 1990.

9. O’Brien K, Wright J, Conboy F, Chadwick S, Connolly I, CookP, et al. Effectiveness of early orthodontic treatment with theTwin-block appliance: a multicenter, randomized, controlledtrial. Part 2: psychosocial effects. Am J Orthod DentofacialOrthop 2003;124:488-94.

10. Nguyen QV, Bezemer PD, Habets L, Prahl-Andersen B. Asystematic review of the relationship between overjet size andtraumatic dental injuries. Eur J Orthod. 1999;21:503-15.

11. Koroluk LD, Tulloch JF, Phillips C. Incisor trauma and earlytreatment for Class II Division 1 malocclusion. Am J OrthodDentofacial Orthop 2003;123:117-25.

12. Cooke MS, Wei SH. A comparative study of southern Chineseand British Caucasian cephalometric standards. Angle Orthod1989;59:131-8.

13. Hägg U, Taranger J. Maturation indicators and the pubertalgrowth spurt. Am J Orthod 1982;82:299-308.

14. Richmond S, Daniels CP. International comparisons of profes-sional assessments in orthodontics: part 1. Treatment need. Am JOrthod Dentofacial Orthop 1998;113:180-5.

15. Hägg U, Tse EL, Rabie AB, Robinson W. A comparison ofsplinted and banded Herbst appliances: treatment changes andcomplications. Aust Orthod J 2002;18:76-81.

16. Van Beek H. Overjet correction by a combined headgear andactivator. Eur J Orthod 1982;4:279-90.

17. Van Beek H. Combination headgear-activator. J Clin Orthod1984;18:185-9.

18. Clinical orthodontics. St Louis: Mosby; 1966.19. Langlois JH, Kalakanis L, Rubenstein AJ, Larson A, Hallam M,

Smoot M. Maxims or myths of beauty? A meta-analytic andtheoretical review. Psychol Bull 2000;126:390-423.

20. Bull R, Rumsey N. The social psychology of facial appearance.New York: Springer-Verlag; 1988.

21. McNamara JA Jr. Components of Class II malocclusion inchildren 8-10 years of age. Angle Orthod 1981;51:177-202.

22. Pancherz H, Zieber K, Hoyer B. Cephalometric characteristicsof Class II Division 1 and Class II Division 2 malocclusions:a comparative study in children. Angle Orthod 1997;67:111-20.

23. Lau JW, Hägg U. Cephalometric morphology of Chinese withClass II Division 1 malocclusion. Br Dent J 1999;186(4 specno):188-90.

24. Tulloch JFC, Proffit WR, Phillips C. Outcomes in a 2-phaserandomized clinical trial of early Class II treatment. Am J Orthod

th McNamera’s cephalometric method compared with

sttreatmentage, 14 y)

Norm* forage 14 y

Posttreatment(age, 24 y)

Adult malenorm†

Mean SD Mean SD

120.2 119.2 7.1 127.8 134.3 6.893.9 93.9 4.6 95.6 99.8 6.026.5 25.3 32.2 34.5 4.071.8 68.8 4.0 75.2 74.6 5.0

ed wi

Po(

Dentofacial Orthop 2004;125:657-67.



25. Rudolph DJ, White SE, Sinclair PM. Multivariate prediction ofskeletal Class II growth. Am J Orthod Dentofacial Orthop 1998;114:283-91.

26. Klocke A, Nanda RS, Kahl-Nieke B. Skeletal Class II patterns inthe primary dentition. Am J Orthod Dentofacial Orthop 2002;121:596-601.

27. Feldmann I, Lundstrom F, Peck S. Occlusal changes fromadolescence to adulthood in untreated patients with Class IIDivision I deepbite occlusion. Angle Orthod 1999;69:33-8.

28. Bendeus M, Hägg U, Rabie B. Growth and treatment changesin patients treated with a headgear-activator appliance. Am JOrthod Dentofacial Orthop 2002;121:376-84.

29. Precious DS, McFadden LR, Fitch SJ. Orthognathic surgery forchildren. Analysis of 88 consecutive cases. Int J Oral Surg1985;14:466-71.

30. Mihalik CA, Proffit WR, Phillips C. Long-term follow-up ofClass II adults treated with orthodontic camouflage: a compari-son with orthognathic surgery outcomes. Am J Orthod Dentofa-cial Orthop 2003;123:266-78.

31. Cheynet F, Chossegros C, Richard O, Ferrara JJ, Blanc JL.Infectious complications of mandibular osteotomy. Rev StomatolChir Maxillofac 2001;102:26-33.

32. Nardi P, Guarducci M, Cervino M. Orthognathic surgery. Studyof nerve injuries. Minerva Stomatol 2002;51:461-71.

33. Johnston LE. Clinical studies in orthodontics: taking the low road toScotland. In: Trotman CA, McNamara JA, editors. Orthodontictreatment: outcome and effectiveness. Vol 30. Craniofacial GrowthSeries. Ann Arbor: Center for Human Growth and Development,University of Michigan; 1994.

34. Ruf S, Pancherz H. Temporomandibular joint remodeling in
adolescents and young adults during Herbst treatment: a prospec-
tive longitudinal magnetic resonance imaging and cephalometricradiographic investigation. Am J Orthod Dentofacial Orthop1999;115:607-18.

35. Du X, Hägg U, Rabie AB. Effects of headgear Herbst andmandibular step-by-step advancement versus conventional Herbstappliance and maximal jumping of the mandible. Eur J Orthod2002;24:167-74.

36. Hägg U, Du X, Rabie ABM, Bendeus M. What does headgearadd to Herbst treatment and to retention? Semin Orthod 2003;9:57-66.

37. Rabie AB, Wong L, Hägg U. Correlation of replicating cells andosteogenesis in the glenoid fossa during stepwise advancement.Am J Orthod Dentofacial Orthop 2003;123:521-6.

38. Shum L, Rabie AB, Hägg U. Vascular endothelial growth factorexpression and bone formation in posterior glenoid fossa duringstepwise mandibular advancement. Am J Orthod DentofacialOrthop 2004;125:185-90.

39. McNamara JA. A method of cephalometric evaluation. Am JOrthod 1984;86:449-69.

40. Ghafari J, Shofer FS, Jacobsson-Hunt U, Markowitz DL, LasterLL. Headgear versus function regulator in the early treatment ofClass II Divison I malocclusion: a randomized clinical trail. Am JOrthod Dentofacial Orthop 1998;113:51-61.

41. O’Brien K, Wright J, Conboy F, Sanjie Y, Mandall N, ChadwickS, et al. Effectiveness of early orthodontic treatment with theTwin-block appliance: a multicenter, randomized, controlled trial.Part 1: dental and skeletal effects. Am J Orthod Dentofacial Orthop2003;124:234-43.

42. Riolo ML, Moyers RE, McNamara JA, Hunter WS. An Atlas ofCraniofacial Growth. Ann Arbor: Center for Human Growth and
Development, University of Michigan; 1974.

Correction of extreme overjet in 2 phases

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