Tratamiento de una Clase III sin extracción

Nonextraction treatment of a skeletal Class IIIadolescent girl with expansion and facemask:Long-term stabilityRoy SabriBeirut, Lebanon

This article describes the combined use of maxillary expansion and a protraction facemask in the correction of askeletal Class III malocclusion after the patient's pubertal growth spurt. Treatment efficacy and the effects onfacial and smile esthetics are presented. The nonextraction option with an arch-size increase and stability issuesis discussed. (Am J Orthod Dentofacial Orthop 2015;147:252-63)

Treatment of Class III malocclusions in growingchildren is a clinical challenge for the orthodontist.Growth is unpredictable and often unfavorable

with this skeletal pattern. Because of our limited abilityto influence mandibular growth and the possibility ofseparating maxillary sutural attachments, treatmenthas shifted to the maxillary protraction paradigm. More-over, maxillary retrusion was found to be the mostcontributory factor to a skeletal Class III malocclusion.The well-documented literature on greater orthopediceffects in younger children has discouraged cliniciansfrom using facemasks after 10 years of age. This casereport illustrates the long-term positive response tolate facemask therapy and the stability of nonextractiontreatment with increases in the arch perimeters.

DIAGNOSIS AND ETIOLOGY

The patient was a girl, age 12 years 9 months, whosechief complaint was an unpleasant smile and crowdedteeth. Her medical history was noncontributory. Herdental history included routine dental evaluations andrestorations on the maxillary central incisors, first mo-lars, and left first premolar. There were carious lesionson the mesial aspects of the maxillary lateral incisorsand white decalcification spots at the upper third ofthe central incisors. Her oral hygiene was poor, and she

had gingival inflammation. The probable cause of hermalocclusion was a combination of genetic and devel-opmental factors.

The patient had a straight profile with a tendency toupper and lower lip retrusion. The nasolabial angle wasincreased, and the throat length normal. From a frontalview, the face was symmetrical and well balanced. Mildparanasal hollowing was noticed. The lips were compe-tent at rest, and the upper lip vermilion was thin. She hada low lip line upon smiling, displaying half the clinicalcrown height of the maxillary incisors along with themandibular teeth. The smile arc was nonconsonant,with flat maxillary incisal edges not running along thelower lip curvature (Fig 1).

Intraorally, she had an Angle Class I molar relation-ship and an anterior edge-to-edge bite. There was ante-rior crowding, with the maxillary lateral incisors blockedin, and the maxillary and mandibular canines blockedout. The mandibular left canine had a thin band ofattached gingiva. The arch-length deficiencies were10.5 mm in the maxillary arch and 6.5 mm in themandibular arch. The transpalatal arch width at the firstmolars was 31.1 mm, which was smaller than the averagenormal width of 35.4 mm.1 The maxillary left first pre-molar and first molar were in crossbite. The maxillarydental midline was deviated slightly to the patient's rightin relation to the facial midline, whereas the mandibularmidline was deviated to the left, leading to a 3-mmdental midline discrepancy (Figs 1 and 2).

The panoramic radiograph showed a full complementof teeth, including developing third molars. The overallbone level was within normal limits (Fig 3).

The cephalometric analysis showed a skeletal Class IIIanteroposterior relationship evidenced by an ANB angleof 0! and a Wits appraisal of "6 mm. The maxillary and

Clinical associate, Medical Center, American University of Beirut; private practice,Beirut, Lebanon.The author has completed and submitted the ICMJE Form for Disclosure ofPotential 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], December 2013; revised and accepted, January 2014.0889-5406/$36.00Copyright ! 2015 by the American Association of Orthodontists.http://dx.doi.org/10.1016/j.ajodo.2014.01.027

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CASE REPORT

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http://dx.doi.org/10.1016/j.ajodo.2014.01.027

mandibular incisors were upright, and the soft-tissueanalysis confirmed lip retrusion with an increasedvalue of the Holdaway line to the tip of the nose(Fig 4, Table I). The skeletal age as assessed from thelateral cephalometric radiograph was 12 years 8 months.This was evaluated according to the method of Hasseland Farman,2 combining the observations of thehand-wrist changes (Fishman method3) and the changesin the cervical vertebrae during skeletal maturation.

TREATMENT OBJECTIVES

The main objective in treating this malocclusion wasto improve the smile, which was the patient's chiefcomplaint. The crowding and arch-length deficiencyneeded to be corrected and the uprighted maxillaryand mandibular incisors proclined to improve lip sup-port. The skeletal Class III anteroposterior relationshipalso had to be addressed to help correct the anterioredge-to-edge bite and enhance the facial profile and

smile esthetics. Addressing the transverse maxillaryarch deficiency would help achieve an optimal posteriorintercuspation.

TREATMENT ALTERNATIVES

Three treatment options were considered.

1. Extraction of 4 first premolars to reposition theblocked-out canines. The 2 main advantages ofthis treatment option are the efficiency to resolvethe severe arch-length deficiency and the possiblelong-term stability of tooth alignment. Neverthe-less, a 4-premolar extraction treatment would notaddress the upright incisors and the lip retrusion,and might even worsen the profile.

2. Extraction of the maxillary first premolars. Thiswould address the arch-length deficiency that wasmore severe in the maxillary arch, with a less adverseeffect on the profile than would extraction of 4 pre-molars. Class III elastics would help correct the

Fig 1. Pretreatment facial and intraoral photographs (age 12 years 8 months).

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American Journal of Orthodontics and Dentofacial Orthopedics February 2015 # Vol 147 # Issue 2

anterior edge bite and finish in a Class II molar rela-tionship. However, the facial and smile estheticswould not be optimized.

3. Nonextraction with rapid maxillary expansion(RME) and maxillary protraction facemask treat-ment. The arch-length deficiency would be resolvedby transverse and anteroposterior arch expansion.The combined orthopedic effects of RME andthe facemask would bring the maxilla downwardand forward. This would enhance both the profileand the smile esthetics by increasing incisor display.

However, this treatment plan relies on patientcooperation and might have questionable long-term stability.

The nonextraction, RME, and facemask treatmentoption was adopted because it would optimize facialand smile esthetics. Cooperation and stability issueswere discussed with the patient and her parents.

TREATMENT PROGRESS

A tissue-borne appliance with bands attached to thefirst premolars and first molars was used for RME.4 Theappliance was activated by turning the screw once a dayfor 30 days, resulting in approximately 7 mm of archwidening at the level of the first molars (Fig 5). Centralincisor separation and an occlusal radiographconfirmed the midpalatal suture opening (Fig 6). Thescrew was then locked with a double ligature tie, andthe facemask was initiated. The elastics were hookedfrom the first premolar brackets on the RME to thehorizontal outer bow of the facemask in a 30! down-ward and forward direction, delivering 450 g of forceper side for 12 to 14 hours per day (Fig 7, A). The face-mask was worn for a total of 15 months. The RME waskept for 7 months as a stabilizer and replaced by anintraoral splint attached to the first molar bands witha palatal wire and a labial wire with soldered elastic

Fig 3. Pretreatment panoramic radiograph.

Fig 2. Pretreatment dental casts.

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February 2015 # Vol 147 # Issue 2 American Journal of Orthodontics and Dentofacial Orthopedics

hooks (Fig 7, B and C). The mandibular arch was bondedwith edgewise brackets (0.022 3 0.028 in) 11 monthsafter RME was initiated, and the maxillary arch wasbonded 5 months later when the facemask was discon-tinued. A normal progression of archwires, starting with0.014-in nickel-titanium alloy and working up to0.018-in stainless steel, was used to level, align, andcoordinate the arches. Interarch posterior and anteriorelastics were also needed to achieve proper occlusalinterdigitation. Her cooperation was excellent, and theappliances were removed at age 16 years 8 months,3 years after the start of fixed appliance treatment.

Retention consisted of a maxillary Hawley-typeremovable appliance worn full time for 24 months, fol-lowed by 12 months of nighttime wear. The mandibularretainer was a 0.0215-in twisted wire bonded onto thelingual sides of the incisors and canines. The fixedmandibular retainer could be kept permanently toenhance the long-term stability of the results.

The mandibular third molars were extracted 1 yearposttreatment and the maxillary third molars 2 yearslater, after they had fully erupted. A gingival graftwas harvested from the palate and placed on the labialaspect of the mandibular left canine at 30 monthsposttreatment.

TREATMENT RESULTS

Favorable facial changes were observed with betterlip support and an improved nasolabial angle. The smilewas enhanced dramatically; a normal lip line displayingthe whole clinical crown height of the maxillary incisorswith the interdental papilla was observed with no moremandibular tooth display. The smile arc was optimizedwith the incisal edges and cusp tips of the maxillary teethrunning along the curvature of the lower lip. A firstmolar-to-first molar transverse dental projection in aposed smile was obtained (Fig 8). Intraorally, the severearch-length deficiencies were eliminated in both archeswith proclination of the anterior teeth and transversemaxillary arch expansion. The transpalatal first molar

Table I. Cephalometric summary

Measurement NormBefore

treatmentAfter

treatment5 years

posttreatmentSkeletalSNA (!) 82 77 77 78SNB (!) 80 77 77 77ANB (!) 2 0 0 1FH-NA (maxdepth) (!)

90 89 89 90

FH-NP (facialangle) (!)

87 89 89 90

Wits (mm) 1 "6 "1 "3SN-MPA (!) 32 38 37 38FMA (!) 25 26 26 26

DentalU1-SN (!) 103 91 111 109U1-NA (!) 22 15 34 31U1-NA (mm) 4 2 10 10L1-NB (!) 25 15 28 25L1-NB (mm) 4 2 8 8L1-MP (!) 87 80 94 90L1-APo (mm) 1 2 8 8U1-L1 (!) 131 150 113 124

Soft tissueFacial contourangle (!)

11 10 14 15

Holdaway line (mm)Tip of nose 9 11 10 10Subnasale 5 4 4 4Upper lip 0 0 0 0Lower lip 0 0 "1 "1Supramentale 5 4 4 3Pogonion 0 0 0 0

Max, Maxillary.

Fig 4. Pretreatment cephalometric radiograph andtracing.

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width was increased by 5.4 mm to an arch width of36.5 mm (Table II). Excellent tooth alignment wasachieved with optimal overbite and overjet. The maxil-lary canines were seated in Class I, and the buccal occlu-sion was well interdigitated. Themaxillary secondmolarsappeared higher because they were not banded due tothe open-bite tendency. Gingival recession on themandibular left canine was noticed before the graftprocedure. There were white decalcification spots mainlyat the gingival levels of the mandibular left premolarsand first molar (Figs 8 and 9).

The posttreatment panoramic radiograph showedgood overall root parallelism. The supporting tissuesappeared healthy, and no apical blunting was noticeddespite the lengthy treatment time. The third molarbuds appeared at the crestal bone level and were mesially

tipped on the left side (Fig 10); these molars wereextracted later. The posttreatment cephalometric radio-graph and the superimposed tracings showed evendownward and forward facial growth. The improvementof the skeletal Class III was confirmed by a 5-mm reduc-tion of the Wits appraisal and the favorable profilechange by a 3! increase of the facial contour angle.There was clear advancement of the upper and lowerlips, along with growth of the chin and nose. The maxil-lary and mandibular incisors were proclined labially.As expected with facemask treatment, the maxillary firstmolars moved slightly downward and forward. Therewas good vertical control with no change in the mandib-ular plane angle despite the use of mechanics (RMEand facemask) that have a tendency to open the bite(Figs 11 and 12, Table I).

The posttreatment records taken 5 years after fixedappliance removal showed excellent stability of thetreatment results. The profile maintained a mild convex-ity and lip fullness. The remarkable enhancement insmile esthetics was preserved; there were optimal lipline, smile arc, and transverse tooth display withoutblack triangles (Fig 13). Intraorally, the long-term stabil-ity was exceptional 2 years after the removable maxillaryretainer was discontinued. Tooth alignment, optimaloverbite and overjet, well-interdigitated buccal occlu-sion, seated canines, and maxillary arch-width increaseswere maintained. The maxillary second molars were stillout of occlusion and did not settle as would have beenexpected. The grafted band of attached gingiva on themandibular left canine appeared stable with no gingivalrecession (Figs 13 and 14, Table II). The panoramicradiograph showed healthy supporting tissues and

Fig 5. Postexpansion intraoral photographs.

Fig 6. Radiograph showing postexpansion midpalatalsuture opening.

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extracted third molars (Fig 15). The cephalometric radio-graphs and superimposed tracings at posttreatment (age16 years 8 months) and 5 years posttreatment (age21 years 8 months) showed no changes in toothpositions and soft-tissue profile. There was no facialgrowth at 5 years posttreatment except for minor resid-ual growth at the symphysis (Figs 16 and 17).

The final occlusion may be considered short of idealaccording to the American Board of Orthodonticsnorms.5 The maxillary second molars, which were notbanded to prevent bite opening, did not seat spontane-ously and remained out of occlusion at 5 years post-treatment. Excursion movements do not reflectbalancing interferences, which might lead to potentialmyofacial discomfort. The proclination of the maxillaryincisors in compensation for the remaining skeletaldiscrepancy also is short of ideal. However, given thelong-standing stability of the completely functionalocclusion, the risks and benefits of any future interven-tion should be properly weighed. Alignment of thesecond molars with segmental mechanics to controlthe vertical and lingual seating can be achieved. How-ever, it should be combined with selective grinding toprevent occlusal disturbances and compromising ofan overbite that is already less than the optimal 30%and that provides minimal anterior protective guidance,and yet has favorable function and esthetics. If theanterior occlusion becomes traumatic with fremitus ofthe maxillary incisors, interproximal recontouring andretroclination of the mandibular incisors would prob-ably be the likely approaches to achieve a more

favorable overjet and overbite relationship, particularlyin the absence of a Bolton discrepancy.

DISCUSSION

Extractions in orthodontics have historically beencontroversial.6 The frequency of extractions was at itslowest in the 1900s with Angle7 and reached its peakwith Tweed8 in the 1950s for esthetic and stabilityconsiderations. Today, there is increasing evidencethat extractions do not guarantee stability.9,10 Also,the well-documented public preference for fuller andmore protrusive profiles than our customary cephalo-metric standards has favored a return toward nonex-traction treatment.11-14 The 2 most commonly citedreasons for extraction today are crowding and profileconsiderations.15 The treatment decision for thispatient was challenging because she had a “nonextrac-tion profile” and an arch-length deficiency that justifiedextractions. To avoid compromising her facial esthetics,she was treated without extractions by increasing thearch perimeters anteroposteriorly and laterally. Howev-er, this enlargement method of treatment was found tohave the poorest stability results compared with serialextractions, arch maintenance, and extractions in thepermanent dentition.16 The stability of this treatmentresult was probably due to the lengthy stabilizationafter RME (15 months) and the prolonged treatmentwith the fixed appliance (3 years), which allowedenough time for muscle adaptation. Optimal toothinterdigitation, prolonged retention, and the absence

Fig 7. A, Frontal view of patient with facemask; B, occlusal view of intraoral wire splint; C, intraoralfrontal view of soldered elastic hooks.

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of late mandibular growth were also responsible forlong-term stability.17

RME has been shown to increase the perimeter ofthe maxillary arch and can provide space to correctmoderate (3-4 mm) crowding.18,19 An averageincrease in arch perimeter of 4.7 mm for an averagemolar expansion of 6.5 mm has been reported.19,20

To correct the pretreatment maxillary arch-length

deficiency of 10.5 mm, 5 mm were gained from RMEand the remaining 5.5 mm from incisor proclination(3 mm labially). RME can also be beneficial in thetreatment of Class III malocclusions, particularlyborderline cases.21 An assessment of the maxilla afterRME with cone-beam computed tomography hasshown significant displacement of the bones of thecircummaxillary suture in growing children with anoverall movement of the maxilla downward and for-ward.22 Similar effects with forward and downwardrotation of Point A, backward movement of Point B,and clockwise rotation of the mandible have alsobeen found in animal studies.23

These effects with RME can also improve the soft-tissue profile by increasing its convexity.24 Inevitably,there are side effects with RME such as an increase inthe vertical dimension, which did not affect this patientwith an open-bite tendency. In fact, in a study of thelong-term effects of RME, the authors found that the

Fig 8. Posttreatment facial and intraoral photographs (age 16 years 8 months).

Table II. Arch-width measurements (mm)

Arch Maxillary Mandibular

Records date T1 T2 T3 T1 T2 T33-3 31.1 24.6 24.4 20.7 20.1 20.14-4 21.7 27.5 27.3 23.3 25.9 25.15-5 28.7 33.2 32.7 28.6 29.6 29.06-6 31.1 36.5 36.6 35.0 34.8 34.6

T1, Pretreatment; T2, posttreatment; T3, 5 years posttreatment; 3,canine; 4, first premolar; 5, second premolar; 6, first molar.

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mandibular plane angle and the lower anterior facialheight increases were transitory.25

Many studies have documented the orthopediceffect of maxillary protraction facemasks to bringthe maxilla forward and downward, often accompa-nied by downward and backward rotation of themandible and dental changes that are favorable forcorrection of Class III malocclusions.26 It has alsobeen recognized from the beginning that facemasktreatment must start quite early relative to most otherorthodontic treatments. The original guideline byDelaire,27 the initiator of facemask therapy, was tostart before the age of 8 years. Today, there is generalagreement that maxillary skeletal effects are mostlikely in younger children, whereas mostly dental

Fig 9. Posttreatment dental casts.

Fig 10. Posttreatment panoramic radiograph.

Fig 11. Posttreatment cephalometric radiograph andtracing.

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Fig 12. Superimposed pretreatment (solid lines) and posttreatment (dashed lines) cephalometrictracings.

Fig 13. Five-year posttreatment facial and intraoral photographs (age 21 years 8 months)—2 yearswithout the removable maxillary retainer.

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changes occur after 10 years of age.26-33 Thefacemask was started for this patient at 12 years11 months of age after her pubertal growth spurt.The skeletal improvements achieved could not havebeen possible with facemask treatment alone at thisage but were most likely the result of RME. Thefacemask could have enhanced the orthopedic effectof RME and vice versa.26 RME presumably can facili-tate the orthopedic effect of the facemask by disrupt-ing the circummaxillary sutural system.26,34 It couldbe further speculated that this type of tissue-borneacrylic RME provided better anchorage that favoredmore skeletal effects and fewer dental changes.

The combined effect of RME and facemask treatmentwas also instrumental in reestablishing the major com-ponents of a balanced smile for this patient, whosemain concern was her unpleasant smile.35 The down-ward displacement of the maxilla helped to optimizethe lip line and the amount of vertical tooth exposure.The upper lip now reaches the gingival margin upon

Fig 14. Five-year posttreatment dental casts.

Fig 15. Five-year posttreatment panoramic radiograph.

Fig 16. Five-year posttreatment cephalometric radio-graph.

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smiling, displaying the whole clinical crown height of themaxillary incisors compared with a 50% display initially.There was no more mandibular tooth display often asso-ciated with Class III malocclusions. RME and maxillaryprotraction also helped fill the lateral negative spacesor buccal corridors by bringing a wider portion of themaxillary arch forward to fill the intercommissure spacewith a first molar-to-first molar smile.36 The smile arcwas also changed from flat to “consonant,” with theedges of the maxillary anterior teeth running along thecurvature of the lower lip.37 Thus, this treatment wassuccessful in addressing the patient's chief complaint,and the results had a positive psychological impact onher personality and self-esteem.

CONCLUSIONS

The treatment results indicate that a maxillary pro-traction facemask can still be effective after the patient'speak of pubertal growth spurt, despite the consensus inthe literature to start before age 8 years for maximum or-thopedic effects. This finding suggests that individualdentofacial characteristics may allow clinicians to pushthe envelope of treatment beyond central tendenciesof treatment responses. Research may focus on the iden-tification of such characteristics.

The successful expansion with midpalatal sutureopening enhanced the orthopedic effect of the facemask

and vice versa. This combined effect has also remarkablyimproved smile esthetics by optimizing anterior toothdisplay and reducing lateral negative spaces. An addi-tional challenge was met by the long-term stability ofthe treatment results despite anteroposterior and lateralarch expansion with nonextraction treatment dictatedby profile considerations.

REFERENCES

1. Howe RP, McNamara JA Jr, O'Connor KA. An examination ofdental crowding and its relationship to tooth size and arch dimen-sion. Am J Orthod 1983;83:363-73.

2. Hassel B, Farman AG. Skeletal maturation evaluation using cervicalvertebrae. Am J Orthod Dentofacial Orthop 1995;107:58-66.

3. Fishman LS. Radiographic evaluation of skeletal maturation; aclinically oriented method based on hand wrist films. Angle Orthod1982;52:88-112.

4. Haas AJ. Palatal expansion: just the beginning of dentofacialorthopedics. 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 castsand 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 commen-tary. 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 orthodon-tic procedures. Am J Orthod Oral Surg 1944;30:405-28.

9. Little RM, Wallem TR, Riedel RA. Stability and relapse ofmandibular anterior alignment-first premolar extraction casestreated by traditional edgewise orthodontics. Am J Orthod1981;80:349-65.

10. Erdinc AE, Nanda RS, Isiksal E. Relapse of anterior crowding inpatients 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. AngleOrthod 1973;43:34-40.

13. Peck S, Peck H. Frequency of tooth extraction in orthodontictreatment. Am J Orthod 1979;76:491-6.

14. Weintraub J, Vig P, Brown C. The prevalence of orthodonticextractions. 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 JOrthod Dentofacial Orthop 1996;109:393-402.

16. Little RM, Riedel RA, Stein A. Mandibular arch length increase dur-ing the mixed dentition: postretention evaluation of stability andrelapse. Am J Orthod Dentofacial Orthop 1990;97:393-404.

17. Sabri R. Treatment of a severe arch length deficiency with antero-posterior and transverse expansion: long-term stability. Am JOrthod Dentofacial Orthop 2010;137:401-11.

18. Brust EW, McNamara JA Jr. Arch dimensional changes concurrentwith expansion in mixed dentition patients. Craniofacial GrowthSeries. Ann Arbor: Center for Human Growth and Development;University of Michigan; 1995.

19. Adkins MD, Nanda RS, Currier GF. Arch perimeter changes in rapidpalatal expansion. Am J Orthod Dentofacial Orthop 1990;97:194-9.

Fig 17. Superimposed posttreatment (solid lines) and5-years posttreatment (dashed lines) cephalometrictracings.

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http://refhub.elsevier.com/S0889-5406(14)00919-6/sref1





http://refhub.elsevier.com/S0889-5406(14)00919-6/sref3a














































20. Hnat WP, Braun S, Chinhara A, Legan HL. The relationship of archlength to alterations in dental arch width. Am J Orthod DentofacialOrthop 2000;118:184-8.

21. McNamara JA Jr. An orthopedic approach to the treatment of ClassIII malocclusion in young patients. J Clin Orthod 1987;21:598-608.

22. Woller JL. An assessment of the maxilla after rapid maxillaryexpansion using cone beam computed tomography in growingchildren [thesis]. St Louis, Mo: Saint Louis University; 2009.

23. Gardner GE, Kronman JH. Cranioskeletal displacements caused byrapid 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 expan-sion on Holdaway soft tissue measurements. Eur J Orthod 2008;30:239-43.

25. Velazquez P, Benito E, Bravo LA. Rapid maxillary expansion. Astudy of the long-term effects. Am J Orthod Dentofacial Orthop1996;109:361-7.

26. Kim JH, Viana MA, Graber TM, Omerza FF, BeGole EA. The effec-tiveness of protraction face mask therapy: a meta-analysis. Am JOrthod Dentofacial Orthop 1999;115:675-85.

27. Delaire J. Maxillary development revisited: relevance to the ortho-paedic 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 effectiveapplication 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 bymaxillary protraction. Am J Orthod Dentofacial Orthop 1998;114:492-502.

30. Baccetti T, McGill JS, Franchi L, McNamara JA Jr. Tollaro l. Skeletaleffects of early treatment of Class III malocclusion with maxillaryexpansion and face-mask therapy. Am J Orthod Dentofacial Or-thop 1998;113:333-43.

31. Saadia M, Torres E. Sagittal changes after maxillary protractionwith expansion in Class III patients in the primary, mixed andlate mixed dentitions: a longitudinal retrospective study. Am J Or-thod Dentofacial Orthop 2000;117:669-80.

32. Franchi L, Baccetti T, McNamara JA Jr. Postpubertal assessment oftreatment timing for maxillary expansion and protraction therapyfollowed by fixed appliances. Am J Orthod Dentofacial Orthop2004;118:549-59.

33. Wells A, Sarver D, Proffit W. Long-term efficacy of reverse pullheadgear therapy. Angle Orthod 2006;76:915-22.

34. Gautam P, Valiathan A, Adhikari R. Skeletal response to maxillaryprotraction with and without maxillary expansion: a finite elementstudy. Am J Orthod Dentofacial Orthop 2009;135:723-8.

35. Sabri R. The 8 components of a balanced smile. J Clin Orthod2005;39:155-67.

36. Sarver DM, Ackerman MB. Dynamic smile visualization and quan-tification: part 2. Smile analysis and treatment strategies. Am J Or-thod Dentofacial Orthop 2003;124:116-27.

37. Dong JK, Jin TH, Cho HW, Oh SC. The esthetics of the smile: a re-view of some recent studies. Int J Prosthodont 1999;12:9-19.

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Tratamiento de una Clase III sin extracción

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