CASE REPORT
Nonextraction treatment of a skeletal Class III adolescent girl with expansion and facemask: Long-term stability Roy Sabri Beirut, Lebanon This article describes the combined use of maxillary expansion and a protraction facemask in the correction of a skeletal Class III malocclusion after the patient's pubertal growth spurt. Treatment efficacy and the effects on facial and smile esthetics are presented. The nonextraction option with an arch-size increase and stability issues is discussed. (Am J Orthod Dentofacial Orthop 2015;147:252-63)
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reatment of Class III malocclusions in growing children is a clinical challenge for the orthodontist. Growth is unpredictable and often unfavorable with this skeletal pattern. Because of our limited ability to influence mandibular growth and the possibility of separating maxillary sutural attachments, treatment has shifted to the maxillary protraction paradigm. Moreover, maxillary retrusion was found to be the most contributory factor to a skeletal Class III malocclusion. The well-documented literature on greater orthopedic effects in younger children has discouraged clinicians from using facemasks after 10 years of age. This case report illustrates the long-term positive response to late facemask therapy and the stability of nonextraction treatment with increases in the arch perimeters.
DIAGNOSIS AND ETIOLOGY
The patient was a girl, age 12 years 9 months, whose chief complaint was an unpleasant smile and crowded teeth. Her medical history was noncontributory. Her dental history included routine dental evaluations and restorations on the maxillary central incisors, first molars, and left first premolar. There were carious lesions on the mesial aspects of the maxillary lateral incisors and white decalcification spots at the upper third of the central incisors. Her oral hygiene was poor, and she Clinical associate, Medical Center, American University of Beirut; private practice, Beirut, Lebanon. The author has completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Roy Sabri, Independence St, Sodeco, Freij Bldg, PO Box 16-6006, Beirut, Lebanon; e-mail, [email protected]. Submitted, December 2013; revised and accepted, January 2014. 0889-5406/$36.00 Copyright Ó 2015 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2014.01.027
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had gingival inflammation. The probable cause of her malocclusion was a combination of genetic and developmental factors. The patient had a straight profile with a tendency to upper and lower lip retrusion. The nasolabial angle was increased, and the throat length normal. From a frontal view, the face was symmetrical and well balanced. Mild paranasal hollowing was noticed. The lips were competent at rest, and the upper lip vermilion was thin. She had a low lip line upon smiling, displaying half the clinical crown height of the maxillary incisors along with the mandibular teeth. The smile arc was nonconsonant, with flat maxillary incisal edges not running along the lower lip curvature (Fig 1). Intraorally, she had an Angle Class I molar relationship and an anterior edge-to-edge bite. There was anterior crowding, with the maxillary lateral incisors blocked in, and the maxillary and mandibular canines blocked out. The mandibular left canine had a thin band of attached gingiva. The arch-length deficiencies were 10.5 mm in the maxillary arch and 6.5 mm in the mandibular arch. The transpalatal arch width at the first molars was 31.1 mm, which was smaller than the average normal width of 35.4 mm.1 The maxillary left first premolar and first molar were in crossbite. The maxillary dental midline was deviated slightly to the patient's right in relation to the facial midline, whereas the mandibular midline was deviated to the left, leading to a 3-mm dental midline discrepancy (Figs 1 and 2). The panoramic radiograph showed a full complement of teeth, including developing third molars. The overall bone level was within normal limits (Fig 3). The cephalometric analysis showed a skeletal Class III anteroposterior relationship evidenced by an ANB angle of 0 and a Wits appraisal of 6 mm. The maxillary and
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Fig 1. Pretreatment facial and intraoral photographs (age 12 years 8 months).
mandibular incisors were upright, and the soft-tissue analysis confirmed lip retrusion with an increased value of the Holdaway line to the tip of the nose (Fig 4, Table I). The skeletal age as assessed from the lateral cephalometric radiograph was 12 years 8 months. This was evaluated according to the method of Hassel and Farman,2 combining the observations of the hand-wrist changes (Fishman method3) and the changes in the cervical vertebrae during skeletal maturation.
smile esthetics. Addressing the transverse maxillary arch deficiency would help achieve an optimal posterior intercuspation. TREATMENT ALTERNATIVES
Three treatment options were considered. 1.
TREATMENT OBJECTIVES
The main objective in treating this malocclusion was to improve the smile, which was the patient's chief complaint. The crowding and arch-length deficiency needed to be corrected and the uprighted maxillary and mandibular incisors proclined to improve lip support. The skeletal Class III anteroposterior relationship also had to be addressed to help correct the anterior edge-to-edge bite and enhance the facial profile and
2.
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Extraction of 4 first premolars to reposition the blocked-out canines. The 2 main advantages of this treatment option are the efficiency to resolve the severe arch-length deficiency and the possible long-term stability of tooth alignment. Nevertheless, a 4-premolar extraction treatment would not address the upright incisors and the lip retrusion, and might even worsen the profile. Extraction of the maxillary first premolars. This would address the arch-length deficiency that was more severe in the maxillary arch, with a less adverse effect on the profile than would extraction of 4 premolars. Class III elastics would help correct the
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Fig 2. Pretreatment dental casts.
However, this treatment plan relies on patient cooperation and might have questionable longterm stability. The nonextraction, RME, and facemask treatment option was adopted because it would optimize facial and smile esthetics. Cooperation and stability issues were discussed with the patient and her parents. TREATMENT PROGRESS
Fig 3. Pretreatment panoramic radiograph.
3.
anterior edge bite and finish in a Class II molar relationship. However, the facial and smile esthetics would not be optimized. Nonextraction with rapid maxillary expansion (RME) and maxillary protraction facemask treatment. The arch-length deficiency would be resolved by transverse and anteroposterior arch expansion. The combined orthopedic effects of RME and the facemask would bring the maxilla downward and forward. This would enhance both the profile and the smile esthetics by increasing incisor display.
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A tissue-borne appliance with bands attached to the first premolars and first molars was used for RME.4 The appliance was activated by turning the screw once a day for 30 days, resulting in approximately 7 mm of arch widening at the level of the first molars (Fig 5). Central incisor separation and an occlusal radiograph confirmed the midpalatal suture opening (Fig 6). The screw was then locked with a double ligature tie, and the facemask was initiated. The elastics were hooked from the first premolar brackets on the RME to the horizontal outer bow of the facemask in a 30 downward and forward direction, delivering 450 g of force per side for 12 to 14 hours per day (Fig 7, A). The facemask was worn for a total of 15 months. The RME was kept for 7 months as a stabilizer and replaced by an intraoral splint attached to the first molar bands with a palatal wire and a labial wire with soldered elastic
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Table I. Cephalometric summary Before After 5 years Measurement Norm treatment treatment posttreatment Skeletal SNA ( ) 82 77 77 78 SNB ( ) 80 77 77 77 2 0 0 1 ANB ( ) FH-NA (max 90 89 89 90 depth) ( ) FH-NP (facial 87 89 89 90 angle) ( ) Wits (mm) 1 6 1 3 SN-MPA ( ) 32 38 37 38 FMA ( ) 25 26 26 26 Dental U1-SN ( ) 103 91 111 109 U1-NA ( ) 22 15 34 31 U1-NA (mm) 4 2 10 10 L1-NB ( ) 25 15 28 25 L1-NB (mm) 4 2 8 8 L1-MP ( ) 87 80 94 90 L1-APo (mm) 1 2 8 8 U1-L1 ( ) 131 150 113 124 Soft tissue Facial contour 11 10 14 15 angle ( ) Holdaway line (mm) Tip of nose 9 11 10 10 Subnasale 5 4 4 4 Upper lip 0 0 0 0 Lower lip 0 0 1 1 Supramentale 5 4 4 3 Pogonion 0 0 0 0 Max, Maxillary.
Fig 4. Pretreatment cephalometric radiograph and tracing.
hooks (Fig 7, B and C). The mandibular arch was bonded with edgewise brackets (0.022 3 0.028 in) 11 months after RME was initiated, and the maxillary arch was bonded 5 months later when the facemask was discontinued. A normal progression of archwires, starting with 0.014-in nickel-titanium alloy and working up to 0.018-in stainless steel, was used to level, align, and coordinate the arches. Interarch posterior and anterior elastics were also needed to achieve proper occlusal interdigitation. Her cooperation was excellent, and the appliances were removed at age 16 years 8 months, 3 years after the start of fixed appliance treatment. Retention consisted of a maxillary Hawley-type removable appliance worn full time for 24 months, followed by 12 months of nighttime wear. The mandibular retainer was a 0.0215-in twisted wire bonded onto the lingual sides of the incisors and canines. The fixed mandibular retainer could be kept permanently to enhance the long-term stability of the results.
The mandibular third molars were extracted 1 year posttreatment and the maxillary third molars 2 years later, after they had fully erupted. A gingival graft was harvested from the palate and placed on the labial aspect of the mandibular left canine at 30 months posttreatment. TREATMENT RESULTS
Favorable facial changes were observed with better lip support and an improved nasolabial angle. The smile was enhanced dramatically; a normal lip line displaying the whole clinical crown height of the maxillary incisors with the interdental papilla was observed with no more mandibular tooth display. The smile arc was optimized with the incisal edges and cusp tips of the maxillary teeth running along the curvature of the lower lip. A first molar-to-first molar transverse dental projection in a posed smile was obtained (Fig 8). Intraorally, the severe arch-length deficiencies were eliminated in both arches with proclination of the anterior teeth and transverse maxillary arch expansion. The transpalatal first molar
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Fig 5. Postexpansion intraoral photographs.
Fig 6. Radiograph showing postexpansion midpalatal suture opening.
width was increased by 5.4 mm to an arch width of 36.5 mm (Table II). Excellent tooth alignment was achieved with optimal overbite and overjet. The maxillary canines were seated in Class I, and the buccal occlusion was well interdigitated. The maxillary second molars appeared higher because they were not banded due to the open-bite tendency. Gingival recession on the mandibular left canine was noticed before the graft procedure. There were white decalcification spots mainly at the gingival levels of the mandibular left premolars and first molar (Figs 8 and 9). The posttreatment panoramic radiograph showed good overall root parallelism. The supporting tissues appeared healthy, and no apical blunting was noticed despite the lengthy treatment time. The third molar buds appeared at the crestal bone level and were mesially
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tipped on the left side (Fig 10); these molars were extracted later. The posttreatment cephalometric radiograph and the superimposed tracings showed even downward and forward facial growth. The improvement of the skeletal Class III was confirmed by a 5-mm reduction of the Wits appraisal and the favorable profile change by a 3 increase of the facial contour angle. There was clear advancement of the upper and lower lips, along with growth of the chin and nose. The maxillary and mandibular incisors were proclined labially. As expected with facemask treatment, the maxillary first molars moved slightly downward and forward. There was good vertical control with no change in the mandibular plane angle despite the use of mechanics (RME and facemask) that have a tendency to open the bite (Figs 11 and 12, Table I). The posttreatment records taken 5 years after fixed appliance removal showed excellent stability of the treatment results. The profile maintained a mild convexity and lip fullness. The remarkable enhancement in smile esthetics was preserved; there were optimal lip line, smile arc, and transverse tooth display without black triangles (Fig 13). Intraorally, the long-term stability was exceptional 2 years after the removable maxillary retainer was discontinued. Tooth alignment, optimal overbite and overjet, well-interdigitated buccal occlusion, seated canines, and maxillary arch-width increases were maintained. The maxillary second molars were still out of occlusion and did not settle as would have been expected. The grafted band of attached gingiva on the mandibular left canine appeared stable with no gingival recession (Figs 13 and 14, Table II). The panoramic radiograph showed healthy supporting tissues and
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Fig 7. A, Frontal view of patient with facemask; B, occlusal view of intraoral wire splint; C, intraoral frontal view of soldered elastic hooks.
extracted third molars (Fig 15). The cephalometric radiographs and superimposed tracings at posttreatment (age 16 years 8 months) and 5 years posttreatment (age 21 years 8 months) showed no changes in tooth positions and soft-tissue profile. There was no facial growth at 5 years posttreatment except for minor residual growth at the symphysis (Figs 16 and 17). The final occlusion may be considered short of ideal according to the American Board of Orthodontics norms.5 The maxillary second molars, which were not banded to prevent bite opening, did not seat spontaneously and remained out of occlusion at 5 years posttreatment. Excursion movements do not reflect balancing interferences, which might lead to potential myofacial discomfort. The proclination of the maxillary incisors in compensation for the remaining skeletal discrepancy also is short of ideal. However, given the long-standing stability of the completely functional occlusion, the risks and benefits of any future intervention should be properly weighed. Alignment of the second molars with segmental mechanics to control the vertical and lingual seating can be achieved. However, it should be combined with selective grinding to prevent occlusal disturbances and compromising of an overbite that is already less than the optimal 30% and that provides minimal anterior protective guidance, and yet has favorable function and esthetics. If the anterior occlusion becomes traumatic with fremitus of the maxillary incisors, interproximal recontouring and retroclination of the mandibular incisors would probably be the likely approaches to achieve a more
favorable overjet and overbite relationship, particularly in the absence of a Bolton discrepancy. DISCUSSION
Extractions in orthodontics have historically been controversial.6 The frequency of extractions was at its lowest in the 1900s with Angle7 and reached its peak with Tweed8 in the 1950s for esthetic and stability considerations. Today, there is increasing evidence that extractions do not guarantee stability.9,10 Also, the well-documented public preference for fuller and more protrusive profiles than our customary cephalometric standards has favored a return toward nonextraction treatment.11-14 The 2 most commonly cited reasons for extraction today are crowding and profile considerations.15 The treatment decision for this patient was challenging because she had a “nonextraction profile” and an arch-length deficiency that justified extractions. To avoid compromising her facial esthetics, she was treated without extractions by increasing the arch perimeters anteroposteriorly and laterally. However, this enlargement method of treatment was found to have the poorest stability results compared with serial extractions, arch maintenance, and extractions in the permanent dentition.16 The stability of this treatment result was probably due to the lengthy stabilization after RME (15 months) and the prolonged treatment with the fixed appliance (3 years), which allowed enough time for muscle adaptation. Optimal tooth interdigitation, prolonged retention, and the absence
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Fig 8. Posttreatment facial and intraoral photographs (age 16 years 8 months).
Table II. Arch-width measurements (mm) Arch Records date 3-3 4-4 5-5 6-6
Maxillary T1 31.1 21.7 28.7 31.1
T2 24.6 27.5 33.2 36.5
Mandibular T3 24.4 27.3 32.7 36.6
T1 20.7 23.3 28.6 35.0
T2 20.1 25.9 29.6 34.8
T3 20.1 25.1 29.0 34.6
T1, Pretreatment; T2, posttreatment; T3, 5 years posttreatment; 3, canine; 4, first premolar; 5, second premolar; 6, first molar.
of late mandibular growth were also responsible for long-term stability.17 RME has been shown to increase the perimeter of the maxillary arch and can provide space to correct moderate (3-4 mm) crowding.18,19 An average increase in arch perimeter of 4.7 mm for an average molar expansion of 6.5 mm has been reported.19,20 To correct the pretreatment maxillary arch-length
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deficiency of 10.5 mm, 5 mm were gained from RME and the remaining 5.5 mm from incisor proclination (3 mm labially). RME can also be beneficial in the treatment of Class III malocclusions, particularly borderline cases.21 An assessment of the maxilla after RME with cone-beam computed tomography has shown significant displacement of the bones of the circummaxillary suture in growing children with an overall movement of the maxilla downward and forward.22 Similar effects with forward and downward rotation of Point A, backward movement of Point B, and clockwise rotation of the mandible have also been found in animal studies.23 These effects with RME can also improve the softtissue profile by increasing its convexity.24 Inevitably, there are side effects with RME such as an increase in the vertical dimension, which did not affect this patient with an open-bite tendency. In fact, in a study of the long-term effects of RME, the authors found that the
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Fig 9. Posttreatment dental casts.
Fig 10. Posttreatment panoramic radiograph.
mandibular plane angle and the lower anterior facial height increases were transitory.25 Many studies have documented the orthopedic effect of maxillary protraction facemasks to bring the maxilla forward and downward, often accompanied by downward and backward rotation of the mandible and dental changes that are favorable for correction of Class III malocclusions.26 It has also been recognized from the beginning that facemask treatment must start quite early relative to most other orthodontic treatments. The original guideline by Delaire,27 the initiator of facemask therapy, was to start before the age of 8 years. Today, there is general agreement that maxillary skeletal effects are most likely in younger children, whereas mostly dental
Fig 11. Posttreatment cephalometric radiograph and tracing.
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Fig 12. Superimposed pretreatment (solid lines) and posttreatment (dashed lines) cephalometric tracings.
Fig 13. Five-year posttreatment facial and intraoral photographs (age 21 years 8 months)—2 years without the removable maxillary retainer.
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Fig 14. Five-year posttreatment dental casts.
Fig 15. Five-year posttreatment panoramic radiograph.
changes occur after 10 years of age.26-33 The facemask was started for this patient at 12 years 11 months of age after her pubertal growth spurt. The skeletal improvements achieved could not have been possible with facemask treatment alone at this age but were most likely the result of RME. The facemask could have enhanced the orthopedic effect of RME and vice versa.26 RME presumably can facilitate the orthopedic effect of the facemask by disrupting the circummaxillary sutural system.26,34 It could be further speculated that this type of tissue-borne acrylic RME provided better anchorage that favored more skeletal effects and fewer dental changes.
Fig 16. Five-year posttreatment cephalometric radiograph.
The combined effect of RME and facemask treatment was also instrumental in reestablishing the major components of a balanced smile for this patient, whose main concern was her unpleasant smile.35 The downward displacement of the maxilla helped to optimize the lip line and the amount of vertical tooth exposure. The upper lip now reaches the gingival margin upon
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and vice versa. This combined effect has also remarkably improved smile esthetics by optimizing anterior tooth display and reducing lateral negative spaces. An additional challenge was met by the long-term stability of the treatment results despite anteroposterior and lateral arch expansion with nonextraction treatment dictated by profile considerations. REFERENCES
Fig 17. Superimposed posttreatment (solid lines) and 5-years posttreatment (dashed lines) cephalometric tracings.
smiling, displaying the whole clinical crown height of the maxillary incisors compared with a 50% display initially. There was no more mandibular tooth display often associated with Class III malocclusions. RME and maxillary protraction also helped fill the lateral negative spaces or buccal corridors by bringing a wider portion of the maxillary arch forward to fill the intercommissure space with a first molar-to-first molar smile.36 The smile arc was also changed from flat to “consonant,” with the edges of the maxillary anterior teeth running along the curvature of the lower lip.37 Thus, this treatment was successful in addressing the patient's chief complaint, and the results had a positive psychological impact on her personality and self-esteem. CONCLUSIONS
The treatment results indicate that a maxillary protraction facemask can still be effective after the patient's peak of pubertal growth spurt, despite the consensus in the literature to start before age 8 years for maximum orthopedic effects. This finding suggests that individual dentofacial characteristics may allow clinicians to push the envelope of treatment beyond central tendencies of treatment responses. Research may focus on the identification of such characteristics. The successful expansion with midpalatal suture opening enhanced the orthopedic effect of the facemask
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1. Howe RP, McNamara JA Jr, O'Connor KA. An examination of dental crowding and its relationship to tooth size and arch dimension. Am J Orthod 1983;83:363-73. 2. Hassel B, Farman AG. Skeletal maturation evaluation using cervical vertebrae. Am J Orthod Dentofacial Orthop 1995;107:58-66. 3. Fishman LS. Radiographic evaluation of skeletal maturation; a clinically oriented method based on hand wrist films. Angle Orthod 1982;52:88-112. 4. Haas AJ. Palatal expansion: just the beginning of dentofacial orthopedics. Am J Orthod 1970;57:219-55. 5. Casko JS, Vaden JL, Kokich VG, Damone J, James RD, Cangialosi TJ, et al. Objective grading system for dental casts and panoramic radiographs. American Board of Orthodontics. Am J Orthod Dentofacial Orthop 1998;114:589-99. 6. Dewel BF. The Case-Dewey-Cryer extraction debate: a commentary. Am J Orthod 1964;50:862-5. 7. Angle E. Malocclusion of the teeth. 7th ed. Philadelphia: S. S. White Manufacturing; 1907. 8. Tweed CH. Indications for the extraction of the teeth in orthodontic procedures. Am J Orthod Oral Surg 1944;30:405-28. 9. Little RM, Wallem TR, Riedel RA. Stability and relapse of mandibular anterior alignment-first premolar extraction cases treated by traditional edgewise orthodontics. Am J Orthod 1981;80:349-65. 10. Erdinc AE, Nanda RS, Isiksal E. Relapse of anterior crowding in patients treated with extraction and nonextraction of premolars. Am J Orthod Dentofacial Orthop 2006;129:755-84. 11. Peck H, Peck S. A concept of facial esthetics. Angle Orthod 1970; 40:284-316. 12. Foster EJ. Profile preferences among diversified groups. Angle Orthod 1973;43:34-40. 13. Peck S, Peck H. Frequency of tooth extraction in orthodontic treatment. Am J Orthod 1979;76:491-6. 14. Weintraub J, Vig P, Brown C. The prevalence of orthodontic extractions. Am J Orthod Dentofacial Orthop 1989;96:462-6. 15. Baumrind S, Korn E, Boyd R, Maxwell R. The decision to extract: part II. Analysis of clinicians' stated reason for extraction. Am J Orthod Dentofacial Orthop 1996;109:393-402. 16. Little RM, Riedel RA, Stein A. Mandibular arch length increase during the mixed dentition: postretention evaluation of stability and relapse. Am J Orthod Dentofacial Orthop 1990;97:393-404. 17. Sabri R. Treatment of a severe arch length deficiency with anteroposterior and transverse expansion: long-term stability. Am J Orthod Dentofacial Orthop 2010;137:401-11. 18. Brust EW, McNamara JA Jr. Arch dimensional changes concurrent with expansion in mixed dentition patients. Craniofacial Growth Series. Ann Arbor: Center for Human Growth and Development; University of Michigan; 1995. 19. Adkins MD, Nanda RS, Currier GF. Arch perimeter changes in rapid palatal expansion. Am J Orthod Dentofacial Orthop 1990;97: 194-9.
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20. Hnat WP, Braun S, Chinhara A, Legan HL. The relationship of arch length to alterations in dental arch width. Am J Orthod Dentofacial Orthop 2000;118:184-8. 21. McNamara JA Jr. An orthopedic approach to the treatment of Class III malocclusion in young patients. J Clin Orthod 1987;21: 598-608. 22. Woller JL. An assessment of the maxilla after rapid maxillary expansion using cone beam computed tomography in growing children [thesis]. St Louis, Mo: Saint Louis University; 2009. 23. Gardner GE, Kronman JH. Cranioskeletal displacements caused by rapid palatal expansion in the rhesus monkey. Am J Orthod 1971; 59:146-55. 24. Kilic¸ N, Kiki A, Okay M, Erdem A. Effect of rapid maxillary expansion on Holdaway soft tissue measurements. Eur J Orthod 2008; 30:239-43. 25. Velazquez P, Benito E, Bravo LA. Rapid maxillary expansion. A study of the long-term effects. Am J Orthod Dentofacial Orthop 1996;109:361-7. 26. Kim JH, Viana MA, Graber TM, Omerza FF, BeGole EA. The effectiveness of protraction face mask therapy: a meta-analysis. Am J Orthod Dentofacial Orthop 1999;115:675-85. 27. Delaire J. Maxillary development revisited: relevance to the orthopaedic treatment of Class III malocclusions. Eur J Orthod 1997;19: 289-311. 28. Merwin D, Ngan P, H€agg U, Yiu C, Wei SH. Timing for effective application of anteriorly directed orthopedic force to the maxilla. Am J Orthod Dentofacial Orthop 1997;112:292-9.
29. Sung SJ, Baik HS. Assessment of skeletal and dental changes by maxillary protraction. Am J Orthod Dentofacial Orthop 1998; 114:492-502. 30. Baccetti T, McGill JS, Franchi L, McNamara JA Jr. Tollaro l. Skeletal effects of early treatment of Class III malocclusion with maxillary expansion and face-mask therapy. Am J Orthod Dentofacial Orthop 1998;113:333-43. 31. Saadia M, Torres E. Sagittal changes after maxillary protraction with expansion in Class III patients in the primary, mixed and late mixed dentitions: a longitudinal retrospective study. Am J Orthod Dentofacial Orthop 2000;117:669-80. 32. Franchi L, Baccetti T, McNamara JA Jr. Postpubertal assessment of treatment timing for maxillary expansion and protraction therapy followed by fixed appliances. Am J Orthod Dentofacial Orthop 2004;118:549-59. 33. Wells A, Sarver D, Proffit W. Long-term efficacy of reverse pull headgear therapy. Angle Orthod 2006;76:915-22. 34. Gautam P, Valiathan A, Adhikari R. Skeletal response to maxillary protraction with and without maxillary expansion: a finite element study. Am J Orthod Dentofacial Orthop 2009;135:723-8. 35. Sabri R. The 8 components of a balanced smile. J Clin Orthod 2005;39:155-67. 36. Sarver DM, Ackerman MB. Dynamic smile visualization and quantification: part 2. Smile analysis and treatment strategies. Am J Orthod Dentofacial Orthop 2003;124:116-27. 37. Dong JK, Jin TH, Cho HW, Oh SC. The esthetics of the smile: a review of some recent studies. Int J Prosthodont 1999;12:9-19.
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Nonextraction treatment of a skeletal Class III adolescent girl with expansion and facemask: Long-term stability Roy Sabri Beirut, Lebanon This article describes the combined use of maxillary expansion and a protraction facemask in the correction of a skeletal Class III malocclusion after the patient's pubertal growth spurt. Treatment efficacy and the effects on facial and smile esthetics are presented. The nonextraction option with an arch-size increase and stability issues is discussed. (Am J Orthod Dentofacial Orthop 2015;147:252-63)
T
reatment of Class III malocclusions in growing children is a clinical challenge for the orthodontist. Growth is unpredictable and often unfavorable with this skeletal pattern. Because of our limited ability to influence mandibular growth and the possibility of separating maxillary sutural attachments, treatment has shifted to the maxillary protraction paradigm. Moreover, maxillary retrusion was found to be the most contributory factor to a skeletal Class III malocclusion. The well-documented literature on greater orthopedic effects in younger children has discouraged clinicians from using facemasks after 10 years of age. This case report illustrates the long-term positive response to late facemask therapy and the stability of nonextraction treatment with increases in the arch perimeters.
DIAGNOSIS AND ETIOLOGY
The patient was a girl, age 12 years 9 months, whose chief complaint was an unpleasant smile and crowded teeth. Her medical history was noncontributory. Her dental history included routine dental evaluations and restorations on the maxillary central incisors, first molars, and left first premolar. There were carious lesions on the mesial aspects of the maxillary lateral incisors and white decalcification spots at the upper third of the central incisors. Her oral hygiene was poor, and she Clinical associate, Medical Center, American University of Beirut; private practice, Beirut, Lebanon. The author has completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Roy Sabri, Independence St, Sodeco, Freij Bldg, PO Box 16-6006, Beirut, Lebanon; e-mail, [email protected]. Submitted, December 2013; revised and accepted, January 2014. 0889-5406/$36.00 Copyright Ó 2015 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2014.01.027
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had gingival inflammation. The probable cause of her malocclusion was a combination of genetic and developmental factors. The patient had a straight profile with a tendency to upper and lower lip retrusion. The nasolabial angle was increased, and the throat length normal. From a frontal view, the face was symmetrical and well balanced. Mild paranasal hollowing was noticed. The lips were competent at rest, and the upper lip vermilion was thin. She had a low lip line upon smiling, displaying half the clinical crown height of the maxillary incisors along with the mandibular teeth. The smile arc was nonconsonant, with flat maxillary incisal edges not running along the lower lip curvature (Fig 1). Intraorally, she had an Angle Class I molar relationship and an anterior edge-to-edge bite. There was anterior crowding, with the maxillary lateral incisors blocked in, and the maxillary and mandibular canines blocked out. The mandibular left canine had a thin band of attached gingiva. The arch-length deficiencies were 10.5 mm in the maxillary arch and 6.5 mm in the mandibular arch. The transpalatal arch width at the first molars was 31.1 mm, which was smaller than the average normal width of 35.4 mm.1 The maxillary left first premolar and first molar were in crossbite. The maxillary dental midline was deviated slightly to the patient's right in relation to the facial midline, whereas the mandibular midline was deviated to the left, leading to a 3-mm dental midline discrepancy (Figs 1 and 2). The panoramic radiograph showed a full complement of teeth, including developing third molars. The overall bone level was within normal limits (Fig 3). The cephalometric analysis showed a skeletal Class III anteroposterior relationship evidenced by an ANB angle of 0 and a Wits appraisal of 6 mm. The maxillary and
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Fig 1. Pretreatment facial and intraoral photographs (age 12 years 8 months).
mandibular incisors were upright, and the soft-tissue analysis confirmed lip retrusion with an increased value of the Holdaway line to the tip of the nose (Fig 4, Table I). The skeletal age as assessed from the lateral cephalometric radiograph was 12 years 8 months. This was evaluated according to the method of Hassel and Farman,2 combining the observations of the hand-wrist changes (Fishman method3) and the changes in the cervical vertebrae during skeletal maturation.
smile esthetics. Addressing the transverse maxillary arch deficiency would help achieve an optimal posterior intercuspation. TREATMENT ALTERNATIVES
Three treatment options were considered. 1.
TREATMENT OBJECTIVES
The main objective in treating this malocclusion was to improve the smile, which was the patient's chief complaint. The crowding and arch-length deficiency needed to be corrected and the uprighted maxillary and mandibular incisors proclined to improve lip support. The skeletal Class III anteroposterior relationship also had to be addressed to help correct the anterior edge-to-edge bite and enhance the facial profile and
2.
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Extraction of 4 first premolars to reposition the blocked-out canines. The 2 main advantages of this treatment option are the efficiency to resolve the severe arch-length deficiency and the possible long-term stability of tooth alignment. Nevertheless, a 4-premolar extraction treatment would not address the upright incisors and the lip retrusion, and might even worsen the profile. Extraction of the maxillary first premolars. This would address the arch-length deficiency that was more severe in the maxillary arch, with a less adverse effect on the profile than would extraction of 4 premolars. Class III elastics would help correct the
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Fig 2. Pretreatment dental casts.
However, this treatment plan relies on patient cooperation and might have questionable longterm stability. The nonextraction, RME, and facemask treatment option was adopted because it would optimize facial and smile esthetics. Cooperation and stability issues were discussed with the patient and her parents. TREATMENT PROGRESS
Fig 3. Pretreatment panoramic radiograph.
3.
anterior edge bite and finish in a Class II molar relationship. However, the facial and smile esthetics would not be optimized. Nonextraction with rapid maxillary expansion (RME) and maxillary protraction facemask treatment. The arch-length deficiency would be resolved by transverse and anteroposterior arch expansion. The combined orthopedic effects of RME and the facemask would bring the maxilla downward and forward. This would enhance both the profile and the smile esthetics by increasing incisor display.
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A tissue-borne appliance with bands attached to the first premolars and first molars was used for RME.4 The appliance was activated by turning the screw once a day for 30 days, resulting in approximately 7 mm of arch widening at the level of the first molars (Fig 5). Central incisor separation and an occlusal radiograph confirmed the midpalatal suture opening (Fig 6). The screw was then locked with a double ligature tie, and the facemask was initiated. The elastics were hooked from the first premolar brackets on the RME to the horizontal outer bow of the facemask in a 30 downward and forward direction, delivering 450 g of force per side for 12 to 14 hours per day (Fig 7, A). The facemask was worn for a total of 15 months. The RME was kept for 7 months as a stabilizer and replaced by an intraoral splint attached to the first molar bands with a palatal wire and a labial wire with soldered elastic
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Table I. Cephalometric summary Before After 5 years Measurement Norm treatment treatment posttreatment Skeletal SNA ( ) 82 77 77 78 SNB ( ) 80 77 77 77 2 0 0 1 ANB ( ) FH-NA (max 90 89 89 90 depth) ( ) FH-NP (facial 87 89 89 90 angle) ( ) Wits (mm) 1 6 1 3 SN-MPA ( ) 32 38 37 38 FMA ( ) 25 26 26 26 Dental U1-SN ( ) 103 91 111 109 U1-NA ( ) 22 15 34 31 U1-NA (mm) 4 2 10 10 L1-NB ( ) 25 15 28 25 L1-NB (mm) 4 2 8 8 L1-MP ( ) 87 80 94 90 L1-APo (mm) 1 2 8 8 U1-L1 ( ) 131 150 113 124 Soft tissue Facial contour 11 10 14 15 angle ( ) Holdaway line (mm) Tip of nose 9 11 10 10 Subnasale 5 4 4 4 Upper lip 0 0 0 0 Lower lip 0 0 1 1 Supramentale 5 4 4 3 Pogonion 0 0 0 0 Max, Maxillary.
Fig 4. Pretreatment cephalometric radiograph and tracing.
hooks (Fig 7, B and C). The mandibular arch was bonded with edgewise brackets (0.022 3 0.028 in) 11 months after RME was initiated, and the maxillary arch was bonded 5 months later when the facemask was discontinued. A normal progression of archwires, starting with 0.014-in nickel-titanium alloy and working up to 0.018-in stainless steel, was used to level, align, and coordinate the arches. Interarch posterior and anterior elastics were also needed to achieve proper occlusal interdigitation. Her cooperation was excellent, and the appliances were removed at age 16 years 8 months, 3 years after the start of fixed appliance treatment. Retention consisted of a maxillary Hawley-type removable appliance worn full time for 24 months, followed by 12 months of nighttime wear. The mandibular retainer was a 0.0215-in twisted wire bonded onto the lingual sides of the incisors and canines. The fixed mandibular retainer could be kept permanently to enhance the long-term stability of the results.
The mandibular third molars were extracted 1 year posttreatment and the maxillary third molars 2 years later, after they had fully erupted. A gingival graft was harvested from the palate and placed on the labial aspect of the mandibular left canine at 30 months posttreatment. TREATMENT RESULTS
Favorable facial changes were observed with better lip support and an improved nasolabial angle. The smile was enhanced dramatically; a normal lip line displaying the whole clinical crown height of the maxillary incisors with the interdental papilla was observed with no more mandibular tooth display. The smile arc was optimized with the incisal edges and cusp tips of the maxillary teeth running along the curvature of the lower lip. A first molar-to-first molar transverse dental projection in a posed smile was obtained (Fig 8). Intraorally, the severe arch-length deficiencies were eliminated in both arches with proclination of the anterior teeth and transverse maxillary arch expansion. The transpalatal first molar
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Fig 5. Postexpansion intraoral photographs.
Fig 6. Radiograph showing postexpansion midpalatal suture opening.
width was increased by 5.4 mm to an arch width of 36.5 mm (Table II). Excellent tooth alignment was achieved with optimal overbite and overjet. The maxillary canines were seated in Class I, and the buccal occlusion was well interdigitated. The maxillary second molars appeared higher because they were not banded due to the open-bite tendency. Gingival recession on the mandibular left canine was noticed before the graft procedure. There were white decalcification spots mainly at the gingival levels of the mandibular left premolars and first molar (Figs 8 and 9). The posttreatment panoramic radiograph showed good overall root parallelism. The supporting tissues appeared healthy, and no apical blunting was noticed despite the lengthy treatment time. The third molar buds appeared at the crestal bone level and were mesially
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tipped on the left side (Fig 10); these molars were extracted later. The posttreatment cephalometric radiograph and the superimposed tracings showed even downward and forward facial growth. The improvement of the skeletal Class III was confirmed by a 5-mm reduction of the Wits appraisal and the favorable profile change by a 3 increase of the facial contour angle. There was clear advancement of the upper and lower lips, along with growth of the chin and nose. The maxillary and mandibular incisors were proclined labially. As expected with facemask treatment, the maxillary first molars moved slightly downward and forward. There was good vertical control with no change in the mandibular plane angle despite the use of mechanics (RME and facemask) that have a tendency to open the bite (Figs 11 and 12, Table I). The posttreatment records taken 5 years after fixed appliance removal showed excellent stability of the treatment results. The profile maintained a mild convexity and lip fullness. The remarkable enhancement in smile esthetics was preserved; there were optimal lip line, smile arc, and transverse tooth display without black triangles (Fig 13). Intraorally, the long-term stability was exceptional 2 years after the removable maxillary retainer was discontinued. Tooth alignment, optimal overbite and overjet, well-interdigitated buccal occlusion, seated canines, and maxillary arch-width increases were maintained. The maxillary second molars were still out of occlusion and did not settle as would have been expected. The grafted band of attached gingiva on the mandibular left canine appeared stable with no gingival recession (Figs 13 and 14, Table II). The panoramic radiograph showed healthy supporting tissues and
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Fig 7. A, Frontal view of patient with facemask; B, occlusal view of intraoral wire splint; C, intraoral frontal view of soldered elastic hooks.
extracted third molars (Fig 15). The cephalometric radiographs and superimposed tracings at posttreatment (age 16 years 8 months) and 5 years posttreatment (age 21 years 8 months) showed no changes in tooth positions and soft-tissue profile. There was no facial growth at 5 years posttreatment except for minor residual growth at the symphysis (Figs 16 and 17). The final occlusion may be considered short of ideal according to the American Board of Orthodontics norms.5 The maxillary second molars, which were not banded to prevent bite opening, did not seat spontaneously and remained out of occlusion at 5 years posttreatment. Excursion movements do not reflect balancing interferences, which might lead to potential myofacial discomfort. The proclination of the maxillary incisors in compensation for the remaining skeletal discrepancy also is short of ideal. However, given the long-standing stability of the completely functional occlusion, the risks and benefits of any future intervention should be properly weighed. Alignment of the second molars with segmental mechanics to control the vertical and lingual seating can be achieved. However, it should be combined with selective grinding to prevent occlusal disturbances and compromising of an overbite that is already less than the optimal 30% and that provides minimal anterior protective guidance, and yet has favorable function and esthetics. If the anterior occlusion becomes traumatic with fremitus of the maxillary incisors, interproximal recontouring and retroclination of the mandibular incisors would probably be the likely approaches to achieve a more
favorable overjet and overbite relationship, particularly in the absence of a Bolton discrepancy. DISCUSSION
Extractions in orthodontics have historically been controversial.6 The frequency of extractions was at its lowest in the 1900s with Angle7 and reached its peak with Tweed8 in the 1950s for esthetic and stability considerations. Today, there is increasing evidence that extractions do not guarantee stability.9,10 Also, the well-documented public preference for fuller and more protrusive profiles than our customary cephalometric standards has favored a return toward nonextraction treatment.11-14 The 2 most commonly cited reasons for extraction today are crowding and profile considerations.15 The treatment decision for this patient was challenging because she had a “nonextraction profile” and an arch-length deficiency that justified extractions. To avoid compromising her facial esthetics, she was treated without extractions by increasing the arch perimeters anteroposteriorly and laterally. However, this enlargement method of treatment was found to have the poorest stability results compared with serial extractions, arch maintenance, and extractions in the permanent dentition.16 The stability of this treatment result was probably due to the lengthy stabilization after RME (15 months) and the prolonged treatment with the fixed appliance (3 years), which allowed enough time for muscle adaptation. Optimal tooth interdigitation, prolonged retention, and the absence
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Fig 8. Posttreatment facial and intraoral photographs (age 16 years 8 months).
Table II. Arch-width measurements (mm) Arch Records date 3-3 4-4 5-5 6-6
Maxillary T1 31.1 21.7 28.7 31.1
T2 24.6 27.5 33.2 36.5
Mandibular T3 24.4 27.3 32.7 36.6
T1 20.7 23.3 28.6 35.0
T2 20.1 25.9 29.6 34.8
T3 20.1 25.1 29.0 34.6
T1, Pretreatment; T2, posttreatment; T3, 5 years posttreatment; 3, canine; 4, first premolar; 5, second premolar; 6, first molar.
of late mandibular growth were also responsible for long-term stability.17 RME has been shown to increase the perimeter of the maxillary arch and can provide space to correct moderate (3-4 mm) crowding.18,19 An average increase in arch perimeter of 4.7 mm for an average molar expansion of 6.5 mm has been reported.19,20 To correct the pretreatment maxillary arch-length
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deficiency of 10.5 mm, 5 mm were gained from RME and the remaining 5.5 mm from incisor proclination (3 mm labially). RME can also be beneficial in the treatment of Class III malocclusions, particularly borderline cases.21 An assessment of the maxilla after RME with cone-beam computed tomography has shown significant displacement of the bones of the circummaxillary suture in growing children with an overall movement of the maxilla downward and forward.22 Similar effects with forward and downward rotation of Point A, backward movement of Point B, and clockwise rotation of the mandible have also been found in animal studies.23 These effects with RME can also improve the softtissue profile by increasing its convexity.24 Inevitably, there are side effects with RME such as an increase in the vertical dimension, which did not affect this patient with an open-bite tendency. In fact, in a study of the long-term effects of RME, the authors found that the
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Fig 9. Posttreatment dental casts.
Fig 10. Posttreatment panoramic radiograph.
mandibular plane angle and the lower anterior facial height increases were transitory.25 Many studies have documented the orthopedic effect of maxillary protraction facemasks to bring the maxilla forward and downward, often accompanied by downward and backward rotation of the mandible and dental changes that are favorable for correction of Class III malocclusions.26 It has also been recognized from the beginning that facemask treatment must start quite early relative to most other orthodontic treatments. The original guideline by Delaire,27 the initiator of facemask therapy, was to start before the age of 8 years. Today, there is general agreement that maxillary skeletal effects are most likely in younger children, whereas mostly dental
Fig 11. Posttreatment cephalometric radiograph and tracing.
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Fig 12. Superimposed pretreatment (solid lines) and posttreatment (dashed lines) cephalometric tracings.
Fig 13. Five-year posttreatment facial and intraoral photographs (age 21 years 8 months)—2 years without the removable maxillary retainer.
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Fig 14. Five-year posttreatment dental casts.
Fig 15. Five-year posttreatment panoramic radiograph.
changes occur after 10 years of age.26-33 The facemask was started for this patient at 12 years 11 months of age after her pubertal growth spurt. The skeletal improvements achieved could not have been possible with facemask treatment alone at this age but were most likely the result of RME. The facemask could have enhanced the orthopedic effect of RME and vice versa.26 RME presumably can facilitate the orthopedic effect of the facemask by disrupting the circummaxillary sutural system.26,34 It could be further speculated that this type of tissue-borne acrylic RME provided better anchorage that favored more skeletal effects and fewer dental changes.
Fig 16. Five-year posttreatment cephalometric radiograph.
The combined effect of RME and facemask treatment was also instrumental in reestablishing the major components of a balanced smile for this patient, whose main concern was her unpleasant smile.35 The downward displacement of the maxilla helped to optimize the lip line and the amount of vertical tooth exposure. The upper lip now reaches the gingival margin upon
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and vice versa. This combined effect has also remarkably improved smile esthetics by optimizing anterior tooth display and reducing lateral negative spaces. An additional challenge was met by the long-term stability of the treatment results despite anteroposterior and lateral arch expansion with nonextraction treatment dictated by profile considerations. REFERENCES
Fig 17. Superimposed posttreatment (solid lines) and 5-years posttreatment (dashed lines) cephalometric tracings.
smiling, displaying the whole clinical crown height of the maxillary incisors compared with a 50% display initially. There was no more mandibular tooth display often associated with Class III malocclusions. RME and maxillary protraction also helped fill the lateral negative spaces or buccal corridors by bringing a wider portion of the maxillary arch forward to fill the intercommissure space with a first molar-to-first molar smile.36 The smile arc was also changed from flat to “consonant,” with the edges of the maxillary anterior teeth running along the curvature of the lower lip.37 Thus, this treatment was successful in addressing the patient's chief complaint, and the results had a positive psychological impact on her personality and self-esteem. CONCLUSIONS
The treatment results indicate that a maxillary protraction facemask can still be effective after the patient's peak of pubertal growth spurt, despite the consensus in the literature to start before age 8 years for maximum orthopedic effects. This finding suggests that individual dentofacial characteristics may allow clinicians to push the envelope of treatment beyond central tendencies of treatment responses. Research may focus on the identification of such characteristics. The successful expansion with midpalatal suture opening enhanced the orthopedic effect of the facemask
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1. Howe RP, McNamara JA Jr, O'Connor KA. An examination of dental crowding and its relationship to tooth size and arch dimension. Am J Orthod 1983;83:363-73. 2. Hassel B, Farman AG. Skeletal maturation evaluation using cervical vertebrae. Am J Orthod Dentofacial Orthop 1995;107:58-66. 3. Fishman LS. Radiographic evaluation of skeletal maturation; a clinically oriented method based on hand wrist films. Angle Orthod 1982;52:88-112. 4. Haas AJ. Palatal expansion: just the beginning of dentofacial orthopedics. Am J Orthod 1970;57:219-55. 5. Casko JS, Vaden JL, Kokich VG, Damone J, James RD, Cangialosi TJ, et al. Objective grading system for dental casts and panoramic radiographs. American Board of Orthodontics. Am J Orthod Dentofacial Orthop 1998;114:589-99. 6. Dewel BF. The Case-Dewey-Cryer extraction debate: a commentary. Am J Orthod 1964;50:862-5. 7. Angle E. Malocclusion of the teeth. 7th ed. Philadelphia: S. S. White Manufacturing; 1907. 8. Tweed CH. Indications for the extraction of the teeth in orthodontic procedures. Am J Orthod Oral Surg 1944;30:405-28. 9. Little RM, Wallem TR, Riedel RA. Stability and relapse of mandibular anterior alignment-first premolar extraction cases treated by traditional edgewise orthodontics. Am J Orthod 1981;80:349-65. 10. Erdinc AE, Nanda RS, Isiksal E. Relapse of anterior crowding in patients treated with extraction and nonextraction of premolars. Am J Orthod Dentofacial Orthop 2006;129:755-84. 11. Peck H, Peck S. A concept of facial esthetics. Angle Orthod 1970; 40:284-316. 12. Foster EJ. Profile preferences among diversified groups. Angle Orthod 1973;43:34-40. 13. Peck S, Peck H. Frequency of tooth extraction in orthodontic treatment. Am J Orthod 1979;76:491-6. 14. Weintraub J, Vig P, Brown C. The prevalence of orthodontic extractions. Am J Orthod Dentofacial Orthop 1989;96:462-6. 15. Baumrind S, Korn E, Boyd R, Maxwell R. The decision to extract: part II. Analysis of clinicians' stated reason for extraction. Am J Orthod Dentofacial Orthop 1996;109:393-402. 16. Little RM, Riedel RA, Stein A. Mandibular arch length increase during the mixed dentition: postretention evaluation of stability and relapse. Am J Orthod Dentofacial Orthop 1990;97:393-404. 17. Sabri R. Treatment of a severe arch length deficiency with anteroposterior and transverse expansion: long-term stability. Am J Orthod Dentofacial Orthop 2010;137:401-11. 18. Brust EW, McNamara JA Jr. Arch dimensional changes concurrent with expansion in mixed dentition patients. Craniofacial Growth Series. Ann Arbor: Center for Human Growth and Development; University of Michigan; 1995. 19. Adkins MD, Nanda RS, Currier GF. Arch perimeter changes in rapid palatal expansion. Am J Orthod Dentofacial Orthop 1990;97: 194-9.
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20. Hnat WP, Braun S, Chinhara A, Legan HL. The relationship of arch length to alterations in dental arch width. Am J Orthod Dentofacial Orthop 2000;118:184-8. 21. McNamara JA Jr. An orthopedic approach to the treatment of Class III malocclusion in young patients. J Clin Orthod 1987;21: 598-608. 22. Woller JL. An assessment of the maxilla after rapid maxillary expansion using cone beam computed tomography in growing children [thesis]. St Louis, Mo: Saint Louis University; 2009. 23. Gardner GE, Kronman JH. Cranioskeletal displacements caused by rapid palatal expansion in the rhesus monkey. Am J Orthod 1971; 59:146-55. 24. Kilic¸ N, Kiki A, Okay M, Erdem A. Effect of rapid maxillary expansion on Holdaway soft tissue measurements. Eur J Orthod 2008; 30:239-43. 25. Velazquez P, Benito E, Bravo LA. Rapid maxillary expansion. A study of the long-term effects. Am J Orthod Dentofacial Orthop 1996;109:361-7. 26. Kim JH, Viana MA, Graber TM, Omerza FF, BeGole EA. The effectiveness of protraction face mask therapy: a meta-analysis. Am J Orthod Dentofacial Orthop 1999;115:675-85. 27. Delaire J. Maxillary development revisited: relevance to the orthopaedic treatment of Class III malocclusions. Eur J Orthod 1997;19: 289-311. 28. Merwin D, Ngan P, H€agg U, Yiu C, Wei SH. Timing for effective application of anteriorly directed orthopedic force to the maxilla. Am J Orthod Dentofacial Orthop 1997;112:292-9.
29. Sung SJ, Baik HS. Assessment of skeletal and dental changes by maxillary protraction. Am J Orthod Dentofacial Orthop 1998; 114:492-502. 30. Baccetti T, McGill JS, Franchi L, McNamara JA Jr. Tollaro l. Skeletal effects of early treatment of Class III malocclusion with maxillary expansion and face-mask therapy. Am J Orthod Dentofacial Orthop 1998;113:333-43. 31. Saadia M, Torres E. Sagittal changes after maxillary protraction with expansion in Class III patients in the primary, mixed and late mixed dentitions: a longitudinal retrospective study. Am J Orthod Dentofacial Orthop 2000;117:669-80. 32. Franchi L, Baccetti T, McNamara JA Jr. Postpubertal assessment of treatment timing for maxillary expansion and protraction therapy followed by fixed appliances. Am J Orthod Dentofacial Orthop 2004;118:549-59. 33. Wells A, Sarver D, Proffit W. Long-term efficacy of reverse pull headgear therapy. Angle Orthod 2006;76:915-22. 34. Gautam P, Valiathan A, Adhikari R. Skeletal response to maxillary protraction with and without maxillary expansion: a finite element study. Am J Orthod Dentofacial Orthop 2009;135:723-8. 35. Sabri R. The 8 components of a balanced smile. J Clin Orthod 2005;39:155-67. 36. Sarver DM, Ackerman MB. Dynamic smile visualization and quantification: part 2. Smile analysis and treatment strategies. Am J Orthod Dentofacial Orthop 2003;124:116-27. 37. Dong JK, Jin TH, Cho HW, Oh SC. The esthetics of the smile: a review of some recent studies. Int J Prosthodont 1999;12:9-19.
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