nonsurgical treatment of an adult patient with bilateral ... · 8% to 22% of orthodontic...

CASE REPORT

Nonsurgical treatment of an adult patient withbilateral posterior crossbite

Renkai Liu,a Ma Xiaoqing,b Peter Wamalwa,c and Shu-juan Zoud

Chengdu and Shanghai, China

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106

A woman with an Angle Class III malocclusion and bilateral posterior crossbites complaining of difficulty inchewing was treated orthodontically without surgery. The treatment comprised asymmetric extractions, a remov-able mandibular lingual arch constriction appliance to narrow the mandibular arch, and a standard edgewiseappliance to align the teeth. Pretreatment, posttreatment, and 1-year follow-up records are shown.With this treat-ment strategy of constricting the mandibular arch by using a combination of removable and fixed orthodontic ap-pliances, we achieved a good result with optimal occlusion. (Am J Orthod Dentofacial Orthop 2011;140:106-14)

Posterior crossbite is a common problem in ortho-dontic practice and has been reported to occur in8% to 22% of orthodontic patients.1-3 Posterior

crossbite occurs when the buccal cusps of themaxillary posterior teeth occlude lingually to thebuccal cusps of the corresponding mandibular teeth.The origin and basic mechanisms of posterior crossbiteremain unclear, but various combinations of dental,skeletal, and neuromuscular functional componentsare known to be etiologic factors.4 The most commoncause, however, is a posterior transverse discrepancydue to reduced maxillary dental arch width alone orcombined with increased mandibular arch width.5

The management of a posterior crossbite is based onthe cause of the discrepancy between the maxillary andmandibular arch widths. Treatment usually involves theuse of a maxillary expansion appliance, which can takemany forms. The recommended treatment for youngerpatients is expansion of the maxillary arch with a remov-able expansion plate or a quad-helix appliance aftergrinding the occlusal interferences.6-9 If, however, the

raduate student, Department of Orthodontics, West China College oftology, Sichuan University, Chengdu, China.odontist, BingJiang Clinic, Arrail Dental, Shanghai, China.r dental officer, Department of Dentistry, Kenyatta National Hospital,bi, Kenya; postgraduate student, Department of Orthodontics, West Chinae of Stomatology, Sichuan University, Chengdu, China.ssor, Department of Orthodontics, West China College of Stomatology,an University, Chengdu, China.uthors report no commercial, proprietary, or financial interest in the prod-r companies described in this article.t requests to: Shu-juan Zou, State Key Laboratory of Oral Diseases, Depart-of Orthodontics, West China College of Stomatology, Sichuan University,du, China; e-mail, [email protected], July 2009; revised and accepted, November 2009.5406/$36.00ight � 2011 by the American Association of Orthodontists..1016/j.ajodo.2009.11.017

posterior transverse discrepancy is caused by increasedmandibular arch width only or combined with reducedmaxillary arch width, it is difficult to achieve thedesired effect with fixed appliances and a maxillaryexpansion appliance. Orthodontists have tried toreduce maxillary arch width, but the reduction ofmandibular arch width rarely has been reported.

The purpose of this article was to present an adultwith bilateral posterior crossbites and an excessivelywide mandibular arch treated orthodontically by usinga removable mandibular lingual arch constrictionappliance and fixed orthodontic appliances to reducethe mandibular arch width and correct the posteriortransverse discrepancy.

DIAGNOSIS AND ETIOLOGY

A 24-year-old woman was referred for orthodonticconsultation. Her chief complaint was inability to chewwell because her posterior teeth were not in contactproperly when eating. This was a longstanding problem.The extraoral examination showed that she had a straightprofile with a symmetric face and competent lips (Fig 1).Functional examination showed no abnormal features.Intraorally, she had Class III molar and Class I caninerelationships bilaterally, an anterior crossbite involvingthe maxillary lateral incisors, and a bilateral posteriorcrossbite involving the premolars and molars (Fig 2).

Both arches were U-shaped with mild crowding in theposterior segments. The posterior crossbite was due toan absolute maxillary to mandibular arch width discrep-ancy. The maxillary intermolar width between thecentral fossae of the right and left first molars was54 mm, and the mandibular intermolar width betweenthe mesiobuccal cusps of the left and right first molarswas 58 mm. The maxillary molars were inclined buccally,

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Fig 1. Pretreatment facial and intraoral photographs.

Liu et al 107

and the mandibular molars were tipped lingually. Themandibular arch had a moderate curve of Spee. Themaxillary midline was coincident with the facial midline,but the mandibular midline was deviated 1 mm to theleft. Both maxillary lateral incisors were small.

The panoramic radiograph showed all teeth presentexcept the mandibular right third molar, which wasimpacted. The patient had a large amalgam restorationin the mandibular left second molar, 2 ceramic restora-tions in the maxillary right molars, and mild generalizedperiodontal bone loss, but no active periodontal disease(Fig 3). The cephalometric tracing showed a skeletalClass I jaw relationship (Fig 4, Table I). The patient wasin good general health with no history of major systemicdiseases.

TREATMENT OBJECTIVES

The treatment objectives were to correct the anteriorcrossbite, eliminate the bilateral posterior crossbite byreducing mandibular arch width, resolve the crowding

American Journal of Orthodontics and Dentofacial Orthoped

in the maxillary and mandibular arches, correct themandibular midline deviation, and achieve a normalocclusion with ideal overjet and overbite while maintain-ing the straight pretreatment facial profile.

TREATMENT ALTERNATIVES

We considered that extraction of some mandibularteeth would be required to allow constriction of themandibular arch to correct the bilateral posteriorcrossbite and to allow correction of the anterior cross-bite. Two alternatives were considered and presentedto the patient.

1. Extraction of the mandibular second premolars.This would facilitate easier correction of the poste-rior crossbites and the anterior crowding but wouldinvolve extraction of a healthy tooth on the left sideand leave behind a poorly restored second molar.

2. Extraction of the mandibular right second premolarand left secondmolar. This extraction pattern would

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Fig 2. Pretreatment dental casts.

Fig 3. Pretreatment radiographs.

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provide enough room to retract the posterior teeth,correct the crossbites, and avoid extracting a healthytooth in the mandibular left quadrant where therewas a poorly restored tooth.

The impacted maxillary right molar was to be surgi-cally removed with both options. The patient chose thesecond plan comprising extraction of the mandibularright second premolar and left second molar, andsurgical removal of the impacted molar.

TREATMENT PROGRESS

The proposed orthodontic treatment involved the useof fixed appliances in both arches and a removablemandibular lingual arch constriction appliance. Patientcooperation was required for the removable appliance.Banding and bonding were done from second molar tosecond molar in the maxillary arch and from first molarto first molar in the mandibular arch. A 0.22 3 0.28-instandard edgewise appliance was used. The maxillaryand mandibular arches were leveled and aligned startingwith a 0.014-in nickel-titanium wire and a 0.017 30.025-in beta-titanium wire. During this time, a remov-able lingual arch constriction appliance was used tonarrow the mandibular dental arch (Fig 5). Meanwhile,an asymmetric arm fabricated in 0.9-mm stainless steel

Journal of Orthodontics and Dentofacial Orthopedics

Fig 4. Pretreatment cephalometric tracing.

Table I. Cephalometric summary

Measurement Pretreatment PosttreatmentNormal mean 6 SD(Chinese adult)

SNA (�) 85.5 85.5 81.69 6 2.54SNB (�) 84.5 84.1 78.94 6 2.19ANB (�) 1 1.4 2.75 6 1.16U1 to NA (mm) 6.6 7.1 5.56 6 3.6U1 to NA (�) 28.5 28.1 23.26 6 6.17L1 to NB (mm) 7.3 5.8 5.76 6 2.29L1 to NB (�) 24.8 25.1 27.38 6 4.74Interincisalangle (�)

125.7 125.5 123.22 6 6.18

MP:SN (�) 33.6 33.5 32.85 6 4.21FMIA (�) 66.8 63 54.6 6 6.5

S, Sella; N, nasion; A, A-point; B, B-point; MP, mandibular plane;U1, maxillary central incisor; L1, mandibular central incisor; SN,sella-nasion plane; FMIA, Frankfort-mandibular incisor angle.

Fig 5. The removable mandibular lingual arch constric-tion appliance.

Fig 6. The removable casting splint retainer.

Liu et al 109

wire was placed to distalize the maxillary left secondmolar.

Eight months later, a 0.0193 0.025-in stainless steelwire was placed. Intra-arch elastics were used for spaceclosure, and Class III elastics were used judiciously to


obtain an ideal occlusal relationship. The posteriortransverse discrepancy was fully corrected during thelast 4 months of active treatment. The entire treatmenttook 2 years 10 months, after which all fixed applianceswere removed. A Hawley retainer was used in themaxillary arch, and a removable cast splint wraparoundretainer was placed in the mandibular arch (Fig 6). Thepatient was instructed to use the retainers full time in-definitely. The maxillary left second molar was restoredafter the treatment.


Fig 7. Posttreatment facial and intraoral photographs.

110 Liu et al

TREATMENT RESULTS

Normal functional occlusion was established withnormal overbite and overjet (Figs 7 and 8). The posteriorcrossbites were corrected, and the final molar relationshipwas acceptable. The midlines were coincident with eachother and with the facial midline. The straight facialprofile was largely maintained, and the resulting profilewas satisfactory.

The constriction of the mandibular dental arch wasquite remarkable. On the dental casts, the maxillaryintermolar width between the central fossa of the rightand left first molars decreased by 5.0 mm, and the man-dibular intermolar width between the mesiobuccal cuspsof the left and right first molars decreased by 11.0 mmafter treatment (Table II). The posttreatment radiographsshowed no evidence of root resorption (Fig 9). Thesuperimposed pretreatment and posttreatment cephalo-metric tracings showed no skeletal changes in themaxilla or the mandible (Fig 10, Table I). The patient


was happy with the results achieved and still satisfiedat the 1-year retention appointment (Figs 11 and 12).

DISCUSSION

Posterior crossbites are common problems in ortho-dontic practice. In most cases, posterior transversediscrepancies are due to insufficient maxillary arch width;therefore, expanding the maxillary arch is a major goal ofposterior crossbite treatment. Numerous treatment mo-dalities have been recommended to expand the maxillaryarch.6-9 Orthodontic effects include tooth tipping andbodily movement of the maxillary posterior teeth andthe canines. Midpalatal suture opening is the skeletalresponse to maxillary expansion, particularly in youngpatients.7,10 However, if applied to adult patients, thepossibility of successful palatal expansion is decreased,because the sutures have a more interdigitated form andgreater resistance to mechanical forces.11 In patients, es-pecially adults, when a broad mandibular arch is a factor


Fig 8. Posttreatment dental casts.

Table II. Changes in arch width dimensions

Measurement (mm) Pretreatment PosttreatmentOne-yearfollow-up

Maxillaryintermolar width

54 49 50

Maxillaryinterpremolar width

45 40 40

Mandibularintermolar width

55 44 44

Mandibularinterpremolar width

45 38 38

Maxillary intermolar width, between the central fossae of the rightand left first molars.Maxillary interpremolar width, between the central fossae of theright and left first premolars.Mandibular intermolar width, between the mesiobuccal cusps of theright and left first molars.Mandibular interpremolar width, between the mesiobuccal cusps ofthe right and left first premolars.

Liu et al 111

in the etiology of posterior crossbites, the treatmentapproach should be focused on both arches and not belimited to constricting the maxillary arch.12 Reduction ofthe mandibular arch width has, however, been rarelyreported. So we tried to design a removable mandibularlingual arch constriction appliance to reduce the mandib-ular arch width.


This appliance was fabricated from 0.8-mm stainlesssteel round wire. This wire size was required to generatethe necessary force because of the relatively long freespan of wire. The wire was bent to conform to the shapeof mandibular lingual arch to reduce the patient’sdiscomfort. Two helices were incorporated to increasethe length of the wire and reduce its load around the cur-vature for better force delivery. Activation was done bycompressing the helices so that the force was deliveredby spring action as it opened.

Treatment with a constriction mandibular lingualarch appliance can be used primarily in the permanentdentition to correct a posterior crossbite. The mandib-ular arch width is reduced by decreasing the width ofthe removable mandibular lingual arch moving themolars lingually. To allow this movement, space isrequired in the arch, and this can be obtained by anyspace-gaining method. In this patient, reduction ofthe dental arch was quite remarkable, and the toothaxes returned to normal, which was conducive forperiodontal health.

Decreasing the mandibular arch width is restricted byalveolar bone and the tongue. In most patients with pos-terior crossbite, there is to varying degrees a skeletalcomponent to the problem. In adults, when skeletalgrowth is nearly complete, minor skeletal malocclusions


Fig 9. Posttreatment radiographs.

Fig 10. Superimposed cephalometric tracing.

112 Liu et al

can be camouflaged by orthodontic treatment alone.The constriction mandibular lingual arch can also beused in patients with a mild skeletal malocclusion.

Patients with a broad mandibular arch might havea hypertrophic tongue. Schwenzer et al13 concludedthat the incidence of relapse was less when reductionof tongue size was combined with orthodontictreatment. The size of the tongue might, therefore, bean essential factor in treatment stability.14 We used a re-movable cast splint wraparound retainer, which controlstongue function and position similar to a tongue cribappliance, and restored the mandibular left secondmolar.15 Muscle balance can play a decisive role in finaltooth positions, and mandibular arch retention shouldbe long term. Comparison of the posttreatment dentalcasts and the 1-year posttreatment dental casts showedlittle difference.

CONCLUSIONS

This case demonstrates that a removable mandibularconstriction lingual arch appliance can be an effectivemethod to reduce the width of a wide mandibular archin the permanent dentition.


REFERENCES

1. Kutin G, Hawes RR. Posterior cross-bites in the deciduous andmixed dentitions. Am J Orthod 1969;56:491-504.

2. Heikenheimo K, Salmi K. Need for orthodontic intervention infive-year-old Finnish children. Proc Finn Dent Soc 1987;83:165-9.

3. Egermark-Eriksson I, Carlsson GE, Magnusson T, Thilander B. Alongitudinal study on malocclusion in relation to signs and symp-toms of cranio-mandibular disorders in children and adolescents.Eur J Orthod 1990;12:399-407.

4. Harrison JE, AshbyD. Orthodontic treatment for posterior crossbites.Cochrane Database of Systematic Reviews 2000;1:CD000979.

5. Andrade Ada S, Gamerio GH, Derossi M, Gaviao MB. Posteriorcrossbite and functional changes. A systematic review. Angle Or-thod 2009;79:380-6.

6. Boysen B, La Cour K, Athanasiou AT, Gjessing PE. Threedimensional evaluation of dentoskeletal changes by quad-helixor removable appliances. Br J Orthod 1992;19:97-107.

7. Sandikcioglu M, Hazar S. Skeletal and dental changes aftermaxillary expansion in the mixed dentition. Am J Orthod Dentofa-cial Orthop 1997;111:321-7.

8. Erdinc A, Ugur T, Erbay E. A comparison of different treatmenttechniques for posterior crossbite in the mixed dentition. Am JOrthod Dentofacial Orthop 1999;116:287-300.

9. Bjerklin K. Follow-up control of patients with unilateral posteriorcross-bite treated with expansion plates or the quad-helix appli-ance. J Orofac Orthop 2000;61:112-24.


Fig 11. One-year posttreatment photographs.

Liu et al 113

10. Handelman CS, Wang L, BeGole EA, Haas AJ. Nonsurgical rapidmaxillary expansion in adults: report on 47 cases using the Haasexpander. Angle Orthod 2000;70:129-44.

11. Takeuchi M, Tanaka E, Nonoyama D, Aoyama J, Tanne K. An adultcase of skeletal open bite with a severely narrowedmaxillary dentalarch. Angle Orthod 2002;72:362-70.

12. Bartzela T, Jonas I. Long-term stability of unilateral posteriorcrossbite correction. Angle Orthod 2007;77:237-43.


13. Schwenzer N, Voy ED, Niemczyk HM. Effect of tongue reductionon the orthodontic and surgical treatment of dysgnathia. J Maxil-lofac Surg 1977;5:15-20.

14. Kawakami S, Yokozeki M, Takahashi T, Horiuchi S, Moriyama K.Siblings with spaced arches treated with and without partial glos-sectomy. Am J Orthod Dentofacial Orthop 2005;127:364-73.

15. Huang GJ, Justus R, Kennedy DB, Kokich VG. Stability of anterioropenbite treated with crib therapy. Angle Orthod 1990;60:17-24.


Fig 12. One-year posttreatment dental casts.

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