Skeletal Class 3 Maloccusion

8/3/2019 Skeletal Class 3 Maloccusion

1/14

Case Report

Skeletal Class III Malocclusion with Unilateral Congenitally Missing Maxillary

Incisor Treated by Maxillary Protractor and Edgewise Appliances

Masako Tabuchia; Hayato Fukuokaa; Ken Miyazawab; Shigemi Gotoc

ABSTRACT This case report describes the orthodontic treatment of a 10-year-old female patient

with a combination of Angle Class III malocclusion, a missing maxillary right lateral incisor, asupernumerary tooth with a short root on the lingual side of the maxillary incisor, a skeletal Class IIIjaw base relationship caused by a diminutive maxilla, and retroposition of the maxilla. We chose to

close the space of the missing tooth, as well as the space created by extraction of the maxillarylateral incisor, by forward movement of the canine and premolars using a maxillary protractor withedgewise appliances. As a result, both the maxillary premolars and the molars were movedmesially, and a Class II molar relationship with tight interdigitation was achieved. Our resultssuggest that the combination of maxillary protractor and nontorque brackets was effective not onlyfor correcting skeletal Class III malocclusion, but also for forward movement of the maxillaryposterior teeth. (Angle Orthod 2010;80:405418.)

KEY WORDS: Skeletal Class III; Missing incisor; Maxillary protractor

INTRODUCTION

The characteristics of Class III malocclusion include

a large or protrusive mandible, a deficient or retrusive

maxilla, a protrusive mandibular dentition, a retrusive

maxillary dentition, or any combination of these.13

Among Japanese people, the incidence of Class III

malocclusion is significantly higher than it is among

whites,4,5 and a retruded maxilla is encountered more

often than a large mandible in persons with skeletal

Class III malocclusion.6 In such cases, orthodontic

treatment is needed to correct the skeletal discrepan-

cy. If left untreated, the malocclusion tends to

worsen,7,8 and these patients will ultimately comprise

a substantial percentage of those seeking orthognathic

surgery as adults.9

Congenitally missing teeth affect the occlusal rela-

tionship between the maxilla and the mandible. Class III

is the most frequent malocclusion seen among subjects

who are lacking only maxillary teeth, whereas the

absence of only mandibular teeth is frequently associ-ated with Class II malocclusion. The issue of how to treat

maxillary lateral agenesis with a skeletal Class III jaw

relationship is always a matter of some controversy,

mainly because treatment takes longer, is more difficult,

and can be performed in a variety of ways.The present case report describes orthodontic

treatment for a patient with an Angle Class III

malocclusion, a missing maxillary right lateral incisor,

a peg-shaped maxillary left lateral incisor, a skeletal

Class III jaw base relationship caused by a small

maxilla, and retroposition of the maxilla.

CASE REPORT

Case Summary

A female patient, 10 years and 10 months old, was

brought to the clinic by her parents, who were worried

about the protrusion of the girls mandible and about amaxillary lateral incisor that had not erupted. The

patients medical history showed no contraindications

to orthodontic therapy. In the family history, the girls

mother had mandibular protrusion. The patient had aconcave profile, with protrusion of the lips. Intraorally,

she had an Angle Class III molar and premolar

relationship on the left side and an Angle Class I

molar and premolar relationship on the right side, with

an overbite of +0.8 mm and an overjet of 21.0 mm. A

a Assistant Professor, Department of Orthodontics, School of

Dentistry, Aichi-Gakuin University, Aichi, Japan.b Associate Professor, Department of Orthodontics, School ofDentistry, Aichi-Gakuin University, Aichi, Japan.

c Chair and Chief Professor, Department of Orthodontics,School of Dentistry, Aichi-Gakuin University, Aichi, Japan.

Corresponding author: Masako Tabuchi, Department ofOrthodontics, School of Dentistry, Aichi-Gakuin University, 2-11 Suemori-dori, Chikusa-ku Nagoya 464-8651, Japan(e-mail: [email protected])

Accepted: May 2009. Submitted: December 2008.G 2010 by The EH Angle Education and Research Foundation,Inc.

DOI: 10.2319/122908-661.1 405 Angle Orthodontist, Vol 80, No 2, 2010


2/14

supernumerary tooth was present on the lingual side ofthe maxillary incisors, and it had a short root. The

maxillary left lateral incisor was peg-shaped and small.The maxillary dentition spacing was +5.8 mm, and+2.0 mm was present in the mandibular arch. Themaxillary dental midline was almost coincident with thefacial midline, but the mandibular dental midlinedeviated 1.5 mm to the right with respect to the facialmidline (Figures 1 and 2). Panoramic, periapical, andocclusal radiographs revealed the absence of themaxillary right lateral incisor (Figure 3). Lateral ceph-

alometric measurements (Table 1) showed a skeletalClass III jaw base relationship (ANB 5 22.9u) with themaxilla in retroposition (SNA 5 75.3u) in comparison to

normal values for female Japanese of corresponding

age. The maxillary incisors were labially inclined

relative to the FH plane (U1-to-FH 5 121.6u). The

mandibular incisors were within a range of 1.0standard deviation of the Japanese normative mean

relative to the mandibular plane angle (L1-to-MP 5

97.7u) and FH plane (FMIA 5 53.9u). The size of the

maxilla was small, while the mandible was large.

Diagnosis

The patient was diagnosed with an Angle Class III

malocclusion with a missing maxillary right lateral incisor.

In addition, she had a peg-shaped maxillary left lateral

Figure 1. Pretreatment facial and intraoral photographs.

406 TABUCHI, FUKUOKA, MIYAZAWA, GOTO

Angle Orthodontist, Vol 80, No 2, 2010


3/14

incisor, a skeletal Class III jaw base relationship caused

by a small maxilla, and retroposition of the maxilla.

Treatment Plan

In consultation with the patient and parents, a

treatment plan was devised based on the diagnostic

records, and the following treatment objectives weredeveloped: (1) enucleation of the supernumerary tooth

and the short root on the lingual side of the maxillary

incisors; (2) extraction of the maxillary left lateral incisor

to achieve bilateral symmetry in the absence of the

maxillary right lateral incisor; (3) maxillary protraction

therapy in maxillary retrognathism and production of

skeletal changes with anterior movement of the maxilla;

(4) closure of the space caused by the missing and

extracted teeth by forward movement of the canines

and premolars using a maxillary protractor with edge-

wise appliances; (5) achievement of Class II molar

occlusion and normal incisor relationships with edge-wise appliances; and (6) retention to achieve stabiliza-

tion of improved tooth alignment and facial esthetics.

Treatment Alternatives

The first alternative involved orthodontic treatment

placing the maxillary right canine into its natural position

within the dental archto open space for prosthodontic

replacement of the right lateral incisor. However,

considering esthetic issues as well as the patients

age, we found it difficult to prescribe treatment thatwould require a 10-year-old to use a removableprosthesis until age 18, when she could receive a fixedprosthesis or implant. We felt that the use of aremovable retainer with an artificial lateral incisor duringadolescence might not be easy for the patient.

The second alternative was orthodontic treatment withextraction of the mandibular premolars. The position ofthe mandibular anterior teeth was slightly forward, butaxial inclination was N-L. Retroclination of the mandib-ular permanent incisors has been reported in manystudies of maxillary protraction.10 If the mandibularpremolars were extracted, excessive retroclination ofthe mandibular incisors would a cause for concern.

Our patient was judged as able to obtain excellentocclusion and profile without extraction of the mandib-

ular premolars. In addition, the patient expressed thedesire to avoid extraction, so we opted for mandibularnonextraction therapy.

Treatment Progress

Caries control and oral hygiene instruction wereperformed. Treatment was started in the maxilla byextraction of the supernumerary tooth and the leftlateral incisor. Subsequently, standard edgewise ap-pliances (0.018-inch 3 0.025-inch) were immediately

placed on the maxillary incisors, canines, and firstmolars. After a 7-month period of leveling and mesialspace closure with an elastomeric chain between the

Figure 2. Pretreatment dental casts.

CLASS III MALOCCLUSION TREATED BY PROTRACTOR 407



4/14

incisor and canine, a palatal bar was placed on the firstmolars, together with edgewise appliances on the firstpremolars. At the same time, an open-coil spring wasplaced between the first premolar and the first molar toadvance the first premolar on a 0.016-inch 3 0.016-inch stainless steel wire and maintain rigidity. The

elastic bands were connected from Kobayashi hookson the first premolar to a protractor, and then theintraoral component was pulled forward using about

150 g of elastic force unilaterally in a 20u to 30udirection downward from the occlusal plane. Inaddition, the patient wore a protraction facial maskfor more than 13 hours a day for 18 months, not onlyas anchorage for the advancement of the maxilla butalso to effect mesial movement of the maxillary

posterior teeth. Mesial movement was performed withthe maxillary first premolar, second premolar, and firstmolar, sequentially (Figures 4 and 5). When moving

Figure 3. (A) Pretreatment cephalograph. (B) Pretreatment panoramic radiograph. (C) Occlusal and periapical radiographs.




5/14

the first molar to the mesial, a tip-back bend was given

to the 0.017-inch3 0.025-inch stainless steel wire archto prevent mesial tipping, and the wire was reduced foreasy movement. During mesial movement of the first

molar, fixed appliances were put into place on theremaining teeth. The patient wore Class III elastics.

Finally, both canines were reshaped slightly on theincisal edge. Sixty-six months were needed for

treatment, including time for growth observation.

Retention consisted of a bonded lingual wire on themaxillary and mandibular teeth, including the canines.

In addition, wrap-around retainers were fabricated tomaintain alignment.

RESULTS

As a result of treatment and appliance use, mutually

acceptable overbite and overjet were obtained, and a

Class II molar relationship with tight interdigitation wasachieved. Also, the space in the anterior dental region

was closed. There was an improvement in lip closureand lip protrusion (Figures 6 through 8). Superimposi-

tion of the pretreatment and posttreatment tracingsaccording to anterior cranial base showed that the

SNA angle increased from 75.3u to 77.2u and the SNB

angle decreased from 78.2u to 77.5u, such that theANB angle increased from 22.9u to 20.3u. Ramus

inclination increased from 90.9u to 96.0u. The gonialangle decreased from 127.1u to 122.6u. Mandibular

plane angle (FMA) was almost the same as pretreat-ment. Tipping movements of both maxillary and

mandibular incisors occurred lingually by 17.1u at U1

and by 12.9u at L1, such that the interincisal angle ofthese teeth showed an increase. Furthermore, the

maxillary molars had moved to the mesial with notipping of the posterior crowns (Figure 9; Table 1). The

posttreatment panoramic radiograph showed no root

resorption (Figure 8). There were no signs or symp-toms of any temporomandibular disorder during thetreatment and retention periods. Acceptable occlusion

and facial profile were also maintained during the 3-year retention period (Figures 10 through 13).

DISCUSSION

Maxillary Protractor

Various types of maxillary protractors have beenclinically modified and used for treating patients with

severe skeletal Class III malocclusions.1113 The use ofreverse headgear for the treatment of Class IIImalocclusion was described more than 100 yearsago.14 It has been demonstrated that reverse headgearcan be an effective method in the treatment of Class IIImalocclusion with a retrusive maxilla. Other studieshave confirmed the efficacy of maxillary protractortreatment with rapid maxillary expansion.15,16 Someresearchers have also concluded that protraction

therapy is useful in Class III malocclusions withmaxillary retrognathism and produces favorable den-toalveolar, skeletal, and profile changes.17,18 In the

Table 1. Cephalometric Measurements

Measurement

Pretreatment

(10 y 10 mo)

Posttreatment

(16 y 4 mo)

Postretention

(19 y 5 mo)

SNA angle (u) 75.3 77.2 77.7

SNB angle (u) 78.2 77.5 78.2

ANB angle (u) 22.9 20.3 20.5

Facial angle (u) 86.3 85.9 86.5

Convexity (u) 22.7 2.1 1.3

A-B plane (u) 4.9 1.9 2

FMA (u) 28.4 28.8 28.8

U1-to-FH (u) 121.6 104.5 108

FMIA (u) 53.9 66.8 64.6

Interincisal angle (u) 112.2 142.3 136.6

Gonial angle (u) 127.1 122.6 122.5

Ramus inclination (u) 90.9 96.0 95.8

A9-Ptm9 (mm) 42.2 44.6 45.1

Gn-Cd (mm) 112.6 119.5 120.9

Pog9-Go (mm) 74.9 81.0 81.8

Cd-Go (mm) 53.0 56.9 56.9

Figure 4. Protractor design.




6/14

Figure 5. Intraoral views of treatment. (A) Start of leveling. (B) Start of advancement of the first premolar. (C) End of advancement of the first

premolar and start of advancement of the second premolar. (D) Start of advancement of the first molar. (E) End of space closure.




7/14

present patient, maxillary protractors with fixed appli-

ances were chosen in the hope of not only providing

anchorage for the advancement of the maxilla but also

moving the maxillary posterior teeth mesially.A downward increase in point A has been reported in

recently published clinical studies on maxillary pro-

tractors.19 In addition, animal studies have shown that

the forward movement and anterior displacement of

the maxilla can be proven by histological changes.20,21

In this case, as the cephalometric skeletal structures

changed, the ANB angle showed a significant increase

as the result of an increase in the SNA angle and a

decrease in the SNB angle. It seems that the

orthopedic forces on the maxilla and the mandible

were effective and advantageous for this patient.

Regarding mandibular changes induced by a maxil-

lary protractor, clockwise rotation of the mandible hasbeen reported in several studies.18,2224 Others have also

concluded that the mandible was positioned backward,

and posterior rotation of the mandible was significant

following maxillary protractor therapy. Because the chin

is one of the anchorage regions for a protraction device,

a force can be applied directly to the mandible.10,25 Using

such a device in the present patient, maxillary protractor

therapy resulted in backward relocation of the ramus

plane and closing of the gonial angle, with no significant

Figure 6. Posttreatment facial and intraoral photographs.




8/14

change in the mandibular plane angle. These findingssuggest that the forward movement of point B wasrestricted by changing the mandibular growth andforward movement of the maxilla by the remodeling ofthe circummaxillary sutures. From these results, we

believe that this maxillary protractor therapy led to goodresults skeletally.

Proclination and forward movement of the maxillaryincisors and retroclination of the mandibular incisorshave been reported in many studies of maxillary

protraction.10,23,25,26 In the present patient, both themaxillary incisors and the mandibular incisors weretipped lingually. In addition to providing root buccaltorque, this combination of maxillary protractor andnontorque brackets has also been extremely effective inthe forward displacement of maxillary and alveolar bone.

Orthodontic Treatment in Patients with Missing

Teeth

Congenitally missing teeth affect the occlusalrelationship between the maxilla and the mandible,including the inclination of neighboring teeth, extrusionof antagonistic teeth, and midline shift. In addition,when orthodontic treatment is performed in a patientwith missing teeth, problems concerning the missing

teeth must be considered, along with the relationshipsbetween the jaws, gnathic growth, discrepancy, andesthetic concerns. Therefore, treatment strategies and

decisions about a treatment regimen tend to become

difficult.27 Class III is the most frequent malocclusion

seen in patients with missing maxillary teeth. In

persons with congenitally missing maxillary teeth with

skeletal Class III, the consequences can be significant

and may necessitate surgery.The present patient was diagnosed as having an

Angle Class III malocclusion with the absence of the

maxillary right lateral incisor and a peg-shaped maxillary

left lateral incisor, together with a skeletal Class III jaw

base relationship caused by a small maxilla and retro-

position of the maxilla. Extraction of the small, peg-

shaped left lateral incisor was carried out, along with

treatment to achieve bilateral symmetry. The maxillary

posterior teeth have drifted sufficiently, the spaces have

closed, and there is no tipping of the posterior crowns.

Some authors prefer an implant or prosthetic solution

because they feel that some aspects of space closure

are disadvantageous. When the option is to close thespace left by maxillary lateral incisor agenesis, the

dentist must rely on some important variables such as

the different color, shape, and size of the canine in the

lateral site; the different root prominences; and the

different height of the gingival scallops. On the other

hand, Carlson28 described how the spaces might be

physically closed without orthodontic treatment when

maxillary lateral incisors were missing. He reported that

the space may be closed as long as the facial

Figure 7. Posttreatment dental casts.




9/14

configuration is not adversely affected. In addition,Nordquist et al29 reported a follow-up survey of patientsin whom the maxillary incisor was congenitally absent,and the space was closed by orthodontic treatment andby prosthodontic treatment. There was no difference inocclusal function between the two, and when the spaces

were closed, the periodontium was healthier. Further-more, Senty30 reported that there was no apparentchange in facial balance when maxillary canines were

moved mesially. Therefore, we chose to close the spaceof the missing and extracted teeth by forward movementof the canine and premolars using maxillary protractionwith edgewise appliances. As a result, not only themaxillary premolars but also the molars moved mesially,and a Class II molar relationship with tight interdigitation

was achieved. The root resorption is slightly greater thannormal and the gingival contour is a little higher thannormal, but both are at acceptable levels without

Figure 8. (A) Posttreatment cephalograph. (B) Posttreatment panoramic radiograph.




10/14

significant biological damage. The patient was pleased

with her smile and appearance, and she was happy not

to have required a prosthetic device.

However, we must consider the following two points

about the first premolar with regard to the position of

the canine. First, it is important that the lingual cusp of

the first premolar not cause arthritis of the jaw.

Secondly, rotation should be mesial. Then the first

premolar can serve as an adequate substitute for the

canine, both functionally and esthetically.31

Figure 9. Superimpositions of pretreatment (solid line) and posttreatment (dotted line) cephalometric tracings. (A) Superimposed on sella-nasion

plane at sella. (B) Superimposed on palatal plane at ANS. (C) Superimposed on mandibular plane at menton.




11/14

In addition, many clinical treatments, such as crown

torque, reshaping, and bleaching of the canine, shouldbe considered. These techniques can provide addi-tional improvements that will help mimic the look of a

natural intact dentition and the function of unilateralincisors.32

The duration of treatment for this patient was 66

months, including growth observation, but theresults reinforced by the long-term record make thistreatment outcome very good despite the risks

involved.

CONCLUSION

N The combination of maxillary protractor and non-

torque brackets was effective not only for correcting

skeletal Class III malocclusion but also for accom-

plishing forward movement of the maxillary posterior

teeth.

REFERENCES

1. Campbell PM. The dilemma of Class III treatment. Early or

late? Angle Orthod. 1983;53:175191.

Figure 10. Facial and intraoral photographs 3 years after treatment.




12/14

2. Guyer EC, Ellis EE III, McNamara JA Jr, Behrents RG.Components of Class III malocclusion in juveniles andadolescents. Angle Orthod. 1986;56:730.

3. McNamara JA Jr, Brudon WL. Orthodontic and OrthopedicTreatment in the Mixed Dentition. Ann Arbor, Mich: Need-ham Press; 1993:117129, 283295.

4. Irie M, Nakamura S. Orthopedic approach to severeskeletal Class III malocclusion. Am J Orthod. 1975;67:377392.

5. Thilander B, Myrberg N. The prevalence of malocclusion inSwedish schoolchildren. Scand J Dent Res. 1973;81:1221.

6. Masaki F. The longitudinal study of morphological differenc-es in the cranial base and facial structure between Japaneseand American whites. Nippon Kyosei Shika Gakkai Zasshi.1980;39:436456.

7. Graber TM. Current Orthodontic Concepts and Techniques.Philadelphia, PA: WB Saunders; 1969:927947.

8. Jacobson A, Evans WG, Preston CB, Sadowsky PL.Mandibular prognathism. Am J Orthod. 1974;66:140171.

9. Graber TM. Orthodontics: Principles and Practice. Philadel-

phia, PA: WB Saunders; 1966:709713.10. Kajiyama K, Murakami T, Suzuki A. Comparison of

orthodontic and orthopedic effects of a modified maxillaryprotractor between deciduous and early mixed dentitions.Am J Orthod Dentofacial Orthop. 2004;126(1):2332.

11. Ishii H, Morita S, Takeuchi Y, Nakamura S. Treatment effectof combined maxillary protraction and chincap appliance insevere skeletal Class III cases. Am J Orthod DentofacialOrthop. 1987;92:304312.

12. Baik HS. Clinical results of the maxillary protraction inKorean children. Am J Orthod Dentofacial Orthop. 1995;108(6):583592.

13. Alcan T, Keles A, Erverdi N. The effects of a modifiedprotraction headgear on maxilla. Am J Orthod DentofacialOrthop. 2000;117:2738.

14. Potpeschnigg H. Eine Zahnrichtmaschine. Dtsch Viertel- jahres Z Zahnheilk. 1875;15:3436.

15. McNamara JA Jr. An orthopedic approach to the treatment

of Class III malocclusion in young patients. J Clin Orthod.1987;21:598608.

16. Turley PK. Orthopedic correction of Class III malocclusionwith palatal expansion and custom protraction headgear.

J Clin Orthod. 1988;22:314325.17. Macdonald KE, Kapust AJ, Turley PK. Cephalometric

changes after the correction of class III malocclusion withmaxillary expansion/facemask therapy. Am J Orthod Den-tofacial Orthop. 1999;116:1324.

18. Nartallo-Turley PE, Turley PK. Cephalometric effects ofcombined palatal expansion and facemask therapy on ClassIII malocclusion. Angle Orthod. 1998;68:217224.

19. Shanker S, Ngan P, Wade D, Beck M, Yiu C, Hagg U, WeiSH. Cephalometric A point changes during and after

maxillary protraction and expansion. Am J Orthod Dentofa-

cial Orthop. 1996;110:423430.20. Nanda R. Protraction of maxilla in rhesus monkeys by

controlled extraoral forces. Am J Orthod. 1978;74:121141.

21. Jackson GW, Kokich VG, Shapiro PA. Experimental andpostexperimental response to anteriorly directed extraoralforce in young Macaca nemestrina. Am J Orthod. 1979;75:318333.

22. Ngan P, Hagg U, Yiu C, Merwin D, Wei SH. Soft tissue and

dentoskeletal profile changes associated with maxillaryexpansion and protraction headgear treatment. Am J OrthodDentofacial Orthop. 1996;109:3849.

Figure 11. Dental casts 3 years after treatment.




13/14

23. Kajiyama K, Murakami T, Suzuki A. Evaluation of themodified maxillary protractor applied to Class III malocclu-

sion with retruded maxilla in early mixed dentition.

Am J Orthod Dentofacial Orthop. 2000;118:549559.24. da Silva Filho OG, Magro AC, Capelozza Filho L. Early

treatment of the Class III malocclusion with rapid maxillaryexpansion and maxillary protraction. Am J Orthod Dentofa-cial Orthop. 1998;113:196203.

25. AltugZ, ArslanAD.Skeletal and dentaleffectsof a mini maxillaryprotraction appliance. Angle Orthod. 2006;76:360368.

26. Kapust AJ, Sinclair PM, Turley PK. Cephalometric effects offace mask/expansion therapy in Class III children: a

comparison of three age groups. Am J Orthod DentofacialOrthop. 1998;113:204212.

27. Hirukawa K, Iwata R, Kurosawa M, Kondo T, Goto S.

Statistical investigation about the prevalence of congenitallymissing permanent teeth. Nippon Kyosei Shika GakkaiZasshi. 1999;58:4956.

28. Carlson H. Suggested treatment for missing lateral incisorcases. Angle Orthod. 1952;22:205216.

Figure 12. (A) Cephalograph 3 years after treatment. (B) Panoramic radiograph 3 years after treatment.




14/14

29. Nordquist GG, McNeill RW. Orthodontic vs. restorativetreatment of the congenitally absent lateral incisorlongterm periodontal and occlusal evaluation. J Periodontol.1975;46:139143.

30. Senty EL. The maxillary canine and missing lateralincisors: esthetics and occlusion. Angle Orthod. 1976;46:365371.

31. Terada Y, Yamazaki O, Furusawa H, Hirose H, Miyazaki T,Sasakura H, Hanada K, Hanai N. The unusual alignment withunusual extraction in the upper and lower anterior segments.Nippon Kyosei Shika Gakkai Zasshi. 1982;41:355368.

32. Rosa M, Zachrisson BU. Integrating esthetic dentistry andspace closure in patients with missing maxillary lateralincisors. J Clin Orthod. 2001;35:221234.

Figure 13. Superimposed posttreatment (solid line) and postretention (dotted line) cephalometric tracings.



Documents

Skeletal Class 3 Maloccusion