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CASE REPORT

Class III malocclusion with missing maxillarylateral incisors

Mauro Cozzani,a Luca Lombardo,b and Antonio Graccoa

Ferrara, Italy

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388

A 23-year-old woman with a skeletal Class III relationship, a normal vertical jaw relationship, and missing max-illary lateral incisors was treated with bidimensional fixed edgewise appliance therapy combined with orthog-nathic surgery. A functional and esthetic occlusion in an improved facial profile was established at the end ofthe surgical and orthodontic treatment. Pretreatment, posttreatment, and long-term follow-up records for the pa-tient are presented. (Am J Orthod Dentofacial Orthop 2011;139:388-96)

Class III malocclusion can involve only the denti-tion, or it might be complicated by a poorrelationship between the maxilla and the mandi-

ble. In the former situation, the mandibular first molar ispositioned half a cusp toward the midline with respect tothe maxillary molar, whereas the latter type also involvesa poor relationship between the maxilla and the mandi-ble in the sagittal plane, caused by maxillary retrusion ormandibular protrusion.1 In addition, a retruded maxillais frequently accompanied by skeletal constriction inthe transverse plane.2 The majority of Class III patientshave both dentoalveolar and skeletal components.3-5

Various factors are implicated in the etiology ofa Class III malocclusion: heredity (eg, race), environmen-tal factors (eg, functional anterior deviation of themandible or mouth breathing, which can be a positivestimulus for mandibular growth), and several patholo-gies (eg, pituitary tumors responsible for acromegaly).6

The incidence of this type of malocclusion in whitepopulations varies between 1% and 5%; in Asianpopulations, it reaches an upper range between 9%and 19%; and in Latin populations, it is about 5%.7,8

Early treatment of Class III malocclusion reduces thenecessity of a second phase of treatment.1 Severalstudies have reported that Class III skeletal discrepanciesworsen with age.9,10 Thus, the difficulty in treatingpreadolescent patients successfully increases over time.

ng Professor, Department of Orthodontics, University of Ferrara, Italy.nct Professor, Department of Orthodontics, University of Ferrara, Italy.uthors report no commercial, proprietary, or financial interest in thects or companies described in this article.t requests to: Mauro Cozzani, Department of Orthodontics, University ofa, 44100, Ferrara, Italy; e-mail, [email protected], April 2009; revised and accepted, September 2009.5406/$36.00ight � 2011 by the American Association of Orthodontists..1016/j.ajodo.2009.09.022

Nonetheless, most patients with severe skeletal Class IIImalocclusion are candidates for orthognathic surgery inadulthood, the only means of obtaining functionalocclusion and an esthetically pleasing profile.11Moreover,many adults presenting for comprehensive orthodontictherapy have additional dental and periodontal problemsthat require multidisciplinary treatment approaches.

The aim of this case report was therefore to presentthe interdisciplinary treatment of an adult patient witha Class III malocclusion complicated bymissingmaxillarylateral incisors.

DIAGNOSIS AND ETIOLOGY

A 23-year-old woman reported with the principalcomplaint of unsatisfactory esthetic appearance of herteeth. Her medical history showed no contraindicationto orthodontic therapy, and no history of trauma orserious illness. Facial photographs showed maxillaryretrusion and severe mandibular protrusion with anunesthetic smile (Fig 1). Intraoral examination of themaxillary dental arch showed a transverse skeletalconstriction, a diastema between the central incisors,and congenital absence of the permanent lateral incisors.

In themandibular arch, on the other hand,mild incisorcrowding, and anterior and bilateral crossbite with nega-tive overjet (�6.5 mm) were evident. The tooth discolor-ation was probably due to tetracycline administrationduring dental development. Class III molar and canine re-lationships were observed on both the right and left sides.The mandible deviated toward the right. The maxillaryleft lateral incisor edentulous space had been partiallyclosed by migration of the adjacent teeth (Fig 2).

Evaluation of the panoramic radiograph confirmedthat the maxillary lateral incisors were missing andshowed the impacted maxillary and mandibular thirdmolars (Fig 3). Cephalometric analysis showed a skeletal

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Fig 1. Pretreatment photographs.

Fig 2. Pretreatment dental casts.

Cozzani, Lombardo, and Gracco 389

Class III relationship, normal vertical jaw proportions(SNA-SNP/Go-Gn, 23�), and inclined mandibularincisors (lower incisor^GoGn, 84�).

American Journal of Orthodontics and Dentofacial Orthoped

TREATMENT OBJECTIVES

The skeletal objectives for this patient were correctionof the maxillary position and asymmetrical mandibular

ics March 2011 � Vol 139 � Issue 3

Fig 3. Pretreatment radiographs and cephalometric tracing.

390 Cozzani, Lombardo, and Gracco

prognathism. The dental objective of treatmentwas closure of the lateral incisor spaces to establisha functional occlusion with normal anterior overbiteand overjet.

TREATMENT ALTERNATIVES

Three treatment options were proposed to the patient.The first would involve orthodontic treatment of themax-illary and mandibular arches, reopening of the maxillarylateral incisor space, and surgical treatment to correctthe vertical and sagittal skeletal discrepancies. This optionwould also include replacing the missing maxillary lateralincisors with 2 dental implants. Although this solutionwould produce Class I molar and canine relationships onboth sides, the gingival contour and margin levels wouldbe critical and difficult to control in the long term.

Another option consisted of closing the spaces left bythe congenitally missing teeth before bimaxillary sur-gery. This choice would also require restoration of themaxillary canines to resemble lateral incisors and the firstpremolars to simulate canines.

The third choice was nonsurgical orthodontic treat-ment. This option would involve extraction of the man-dibular first premolars and replacement of the missingmaxillary lateral incisors with 2 dental implants. The

March 2011 � Vol 139 � Issue 3 American

premolar extractions and opening of the lateral incisorspaces would permit resolution of the anterior crossbiteand achieve an occlusal compromise. However, neitherfacial esthetics, skeletal asymmetry, nor the transversediscrepancy would be improved.

After consultation, the patient chose the second op-tion, and her treatment course and outcome are detailedbelow.

TREATMENT PLAN

Levelling and alignment of both arches and closure ofthe lateral incisor spaces were the first steps. Then LeFort Isurgery would be used to correct the vertical and trans-verse skeletal discrepancies and to assist in sagittal coordi-nation of the mandible. Finally, bilateral sagittal splitramus osteotomywould be used to correct the asymmetry,prognathism, sagittal maxillomandibular relationship,and dentalmalocclusion. Thefinal stepswould be occlusalfinishing and restorative rehabilitation of the maxiillarycanines and first premolars to substitute as lateral incisorsand achieve adequate occlusal and esthetic results.

TREATMENT PROGRESS

The mandibular third permanent molars and maxil-lary right deciduous lateral incisor were extracted.

Journal of Orthodontics and Dentofacial Orthopedics

Fig 4. Leveling and alignment.


Although a bidimensional appliance was used initially,the maxillary second molars were not bonded, and themaxillary canines were fitted with conventional fixedappliances (0.022 3 0.028 in) to facilitate slidingmechanics of the maxillary central incisors.

Leveling and alignment were begun with a 0.014-innickel-titanium archwire and completed with a 0.01630.022-in stainless steel wire. Space closure was achievedby using 0.018 3 0.022-in stainless steel archwires, se-lected to maintain incisor torque control (0.018 30.025-in slot) and reduce friction on the canines, premo-lars, and molars during incisor retraction (brackets,0.022 3 0.028 in) (Fig 4).

After bimaxillary surgery, esthetic recontouring ofthe maxillary canines was accomplished by usinga combination of grinding and composite resin buildups(Fig 5). In addition, the maxillary canines, which hadbeen reshaped as lateral incisors, were fitted with new0.018 3 0.025-in brackets (bidimensional prescription)


to provide precise control of torque and tipping, andthe mandibular second molars were banded. After re-bracketing of the maxillary canines (lateral incisors),a 0.016 3 0.022-in Quad-Cat (GAC International,Bohemia, NY) archwire was placed.

Subsequently, space was opened by using an 0.0183 0.025-in stainless steel archwire, and a coil spring onthe left side was used to prepare the first premolars forrestoration with canine-shaped ceramic crowns. Ulti-mately, individualized extrusion and intrusion of thecanines (lateral incisors) and first premolars (canines)were performed to obtain optimum marginal gingivalcontours for the anterior teeth (Fig 6). Final detailing,involving 8 months of treatment time, was completedwith 0.018 3 0.025-in stainless steel archwires.

TREATMENT RESULTS

At the end of treatment, Class I canine and Class IImolar relationships were achieved, and overbite and


Fig 5. Esthetic recontouring of the maxillary canines.

Fig 6. Individualized extrusion and intrusion of the canines (lateral incisors) and first premolars (ca-nines) to improve gingival contours.


overjet were within the normal limits. Facial appearanceand skeletal balance were improved, and mandibularasymmetry and prognathism had been corrected.Despite the missing lateral incisors, the patient


appeared to exhibit a natural intact dentition (Figs 7and 8).

The cephalometric changes included increases inthe ANB angle (almost ideal) and Wits appraisals, an


Fig 7. Posttreatment photographs.

Fig 8. Postreatment dental casts.


improvement in the lip relationship, and no variation inlower vertical face height (Table). Superimposition of thepretreatment and posttreatment cephalometric tracingsshowed that mandibular retraction was achieved byslight downward and forward movement of the maxilla,as well as minor maxillary incisor proclination (Fig 9).

Long-term records were collected 2 years after treat-ment (Figs 10 and 11). Posttreatment and long-termcephalograms and superimposed tracings demonstratedminimal anteroposterior changes in incisor position andlittle or no surgical relapse.

DISCUSSION

Almost 30% of adult orthodontic patients requiremulti-disciplinary management to obtain optimal treat-ment outcomes.12 Often, functional and esthetic results


can only be achieved by a combination of surgery,orthodontics, and prosthodontic rehabilitation.13

In this patient, the missing lateral incisors compli-cated the treatment of the Class III skeletal malocclusion.Orthodontic treatment of missing teeth comprises 2alternatives: closure or opening of the edentulousspaces.14-22 Many clinicians prefer to create space formissing lateral incisors with single-tooth implants orresin-bonded bridges,21,22 but, in this case, we decidedto close the spaces because of the permanence and thebiologic compatibility of the result.23

Managing patients with congenitally missing maxil-lary lateral incisors raises several important issuesconcerning the amount of space, the patient’s age, thetype of malocclusion, and the condition of the adjacentteeth. One of 3 treatment options can be selected when


Fig 9. Posttreatment radiographs and superimposed cephalometric tracings.


replacing missing lateral incisors: canine substitution,a tooth-supported restoration, or a single-toothimplant. There are also specific criteria that must beaddressed when choosing an appropriate treatment op-tion. The primary consideration must be conservation,and, in general, the treatment of choice should be theleast invasive option that satisfies the expected estheticand functional objectives.

In this context, the orthodontist plays a key role byachieving specific space requirements and positioningteeth in an ideal restorative position. For example, caninesubstitution can be an excellent treatment option forreplacing missing lateral incisors from an esthetic perspec-tive. However, if this treatment is unsuitable for the patientin question, the final result might be less than ideal.Ultimately, an interdisciplinary approach is the mostpredictable way of achieving optimal final esthetics.24


According to Rosa and Zachrisson,25,26 Class IIItreatment with space closure can be difficult to obtain,but a natural-looking result is possible with good collab-oration. Fundamental to clinical success are carefulcorrection of the crown torque, esthetic recontouring,and intentional whitening of the mesially relocatedcanine. Furthermore, to obtain an optimal level for themarginal gingival contours of the anterior teeth, individ-ualized extrusion and intrusion of the canines and firstpremolars are necessary.

In contrast, replacing the missing lateral incisors witha single-tooth implant and prosthetic crown wouldcommit the patient to a lifelong artificial restoration ina highly visible area of the mouth. In this region, toothhue and transparency, along with gingival color,contour, and marginal levels are critical and difficult tocontrol, particularly over time.27,28


Fig 10. Photographs 2 years posttreatment.

Fig 11. Cephalometric radiograph and tracing 2 years posttreatment.


American Journal of Orthodontics and Dentofacial Orthopedics March 2011 � Vol 139 � Issue 3

Table. Cephalometric analysis

Initial Final PosttreatmentSagittal skeletal relationshipsMaxillary position: S-N-A (�) 81.5 82 82Mandibular position: S-N-Pg (�) 85 81 81.5Sagittal jaw relationship: A-N-Pg(mm)

�3.5 1 0.5

Vertical skeletal relationshipsMaxillary inclination:S-N/ANS-PNS (�)

13 11.5 11.5

Mandibular inclination:S-N/Go-Gn (�)

36 37 34.5

Vertical jaw relationship:S-N/Go-Gn (mm)

23 23.5 23

Dento-basal relationshipsMaxillary incisor inclination:1-ANS-PNS (�)

116 122 121

Mandibular incisor inclination:1_ -Go-Gn (�)

84 91 90

Mandibular incisorcompensation: 1_ -A-Pg (mm)

2.5 6 5

Dental relationshipsOverjet (mm) �6.5 3 3Overbite (mm) 4.5 2 2.5Interincisal angle: 1/1_ � 136.5 126 127


Treatment outcomes and long-term results demon-strated that combined orthodontic surgery and prostho-dontic treatment of a Class III malocclusion can providea stable, intact dentition, despite the congenital absenceof the lateral incisors.

CONCLUSIONS

Interdisciplinary treatment combining orthodontics,surgery, and prosthodontics helped to achieve good es-thetic and functional results in an adult with a Class IIIskeletal malocclusion and missing lateral incisors.

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14. Carlson H. Suggested treatment for missing lateral incisor cases.Angle Orthod 1952;22:205-16.

15. Asher C, Lewis DH. The integration of orthodontic and restorativeprocedures in cases with missing maxillary incisors. Br Dent J1986;160:241-5.

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