CASE REPORT

Unusual orthodontic approach to a maxillarycanine-premolar transposition and a missinglateral incisor with long-term follow-up

Milton Meri Benitez Farret,a Marcel Marchiori Farret,b Alessandro Marchiori Farret,b and Henrique Hollwegc

Santa Maria, Rio Grande do Sul, Brazil

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In this case report, we present an unusual approach that was used to treat a 14-year-old patient with a bi-lateral canine-premolar transposition and a missing maxillary lateral incisor. The orthodontic treatmentinvolved maintaining the transposition and creating a space for lateral incisor replacement. Toward theend of the treatment, accentuated buccal root torque was performed, and lateral group function was estab-lished to improve the treatment outcome. Finally, an ideal esthetic and functional occlusion was achieved.The 8-year posttreatment follow-up records show the stability of this treatment. (Am J Orthod DentofacialOrthop 2012;142:690-7)

Tooth transposition is a relatively rare condition inwhich a permanent tooth develops and erupts ina position normally occupied by another perma-

nent tooth.1-6 Maxillary canine-premolar transpositionis the most frequent type of tooth transposition, andseveral theories have been proposed to explain thiscondition. Genetic origin,2,4-9 prolonged retention ofdeciduous teeth, supernumerary teeth, and localpathologic processes are some reported causes.3,6-8,10

Transpositions in the mixed dentition are usuallycorrected when the dentoalveolar process has adequatewidth, the canine involved in the transpositionhas not completely erupted, and the transposition isnot yet completed.1,11-13 However, when the teethinvolved have fully erupted and are almost aligned,and the dentoalveolar process is narrow, a satisfactoryresult can be obtained by maintaining the trans-posed teeth, preventing root resorption and gingivalrecession, and avoiding prolonged orthodontictreatment.12-14

ssor and chairman, Department of Orthodontics, Federal University ofMaria, Santa Maria, Rio Grande do Sul, Brazil.te practice, Santa Maria, Rio Grande do Sul, Brazil.ssor, Department of Prosthodontics, Federal University of Santa Maria,Maria, Rio Grande do Sul, Brazil.uthors report no commercial, proprietary, or financial interest in the prod-r companies described in this article.t requests to: Marcel Marchiori Farret, 1000/113 Floriano Peixoto St,Maria, RS, Brazil 97015370; e-mail, marcelfarret@yahoo.com.br.itted, November 2010; revised and accepted, March 2011.5406/$36.00ight � 2012 by the American Association of Orthodontists./dx.doi.org/10.1016/j.ajodo.2011.03.027

Here, we present a patient with bilateral maxillarycanine-premolar transposition and a missing maxillarylateral incisor, who was treated by maintaining thetransposed tooth positions with particular attention tofunction and esthetics. We also present the long-termfollow-up findings.

DIAGNOSIS AND ETIOLOGY

A healthy 14-year-old girl came to us with her par-ents for the treatment of crowding of the teeth inboth arches and the absent maxillary right permanentlateral incisor and left permanent canine. She hada straight profile and symmetric facial development(Fig 1). The intraoral clinical examination showed anAngle Class II malocclusion with left subdivision. Weobserved prolonged retention of both maxillary decid-uous canines, absence of the right lateral incisor,and complete transposition of the right permanentcanine with the first premolar. In addition, a unilateralposterior crossbite on the left side was observed(Fig 2).

The radiographic examination showed completetransposition on the right side and impaction of themaxillary left permanent canine with accentuated mesialinclination and incomplete transposition with the firstpremolar. Moreover, the absence of the maxillary rightlateral incisor was confirmed (Fig 3). Cephalometrically,she had a good facial pattern with the mandibular inci-sors in a good position and the maxillary incisors slightlyretroclined (Fig 4; Table).

Fig 1. Pretreatment facial and intraoral photographs.

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TREATMENT OBJECTIVES

The treatment objectives for this patient were to (1)correct the posterior crossbite on the left side, (2) es-tablish a Class I molar relationship on the left side,(3) extract the maxillary deciduous teeth, (4) maintainthe maxillary canine-premolar transposition on theright side and perform a prosthetic replacement ofthe permanent lateral incisor, (5) move the impactedcanine on the left side while maintaining the transpo-sition, and (6) establish ideal overbite, overjet, and ad-equate occlusion with group function in lateralexcursion.

TREATMENT ALTERNATIVES

Three treatment options were available for this pa-tient. The first was corrective positioning of the trans-posed teeth to their normal positions in the arch.

American Journal of Orthodontics and Dentofacial Orthoped

However, the dentoalveolar width was too narrow topermit the movement of these 2 teeth through thebone, so this treatment option was rejected. The secondoption was extraction of the maxillary first premolars toestablish Class I canine and Class II molar relationships;this option was also discarded, because the maxillaryleft permanent canine was positioned in an accentu-ated distal position and would require orthodonticmovement over a large area to establish the Class I re-lationship.

The third option considered was to maintain thetransposition, moving the right first premolar to the po-sition of the lateral incisor on the right side to achievea Class I relationship and, on the left side, leaving thepremolar in the position of the canine. This alternativewas considered esthetically harmful, because of thechange it would cause in the gingival contour and toothshape and color. Moreover, after the treatment, the

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Fig 2. Pretreatment dental casts.

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lateral function on the right side would be canine disclu-sion, whereas on the left side it would be group function.

Fig 3. Pretreatment radiographs.

TREATMENT PROGRESS

Initially, bonded buttons were placed on the lingualsurfaces of the maxillary left second premolar and firstmolar and on the buccal surfaces of the mandibularleft second premolar and first molar. Subsequently, elas-tics were used over 2 months to correct the crossbite. Inthe third month, a standard edgewise appliance, 0.0223 0.028 in, was bonded on the mandibular arch. Inthe following months, the teeth in the maxillary archwere sequentially bonded, and the deciduous teethwere extracted to permit appropriate aligning andleveling of the arch. To provide adequate area for this,both maxillary canines were not bonded during theinitial period, when the first premolars were movedtoward the mesial aspect. On the left side, the first pre-molar was moved until it established contact with thelateral incisor, and then the canine naturally occupieda favorable position in the arch, as seen in the radio-graphs (Fig 5).

In addition, a coil spring was used between thefirst and second premolars to widen the space,

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Fig 4. Pretreatment cephalogram and tracing.

Table. Cephalometric summary

Measurement Norm Pretreatment* Posttreatmenty

SNA (�) 82 83 81SNB (�) 80 78 78ANB (�) 2 5 3Mx1.NA (�) 22 19 24Mx1-NA (mm) 5 5 6Md1.NB (�) 25 25 24Md1-NB (mm) 5 7 6Mx1.Md1 (�) 131 133 130SN.GoGn (�) 32 29 29FMA (�) 25 21 22FMIA (�) 60 62 62IMPA (�) 95 97 96Upper lip-S line (mm) 0 0 �2Lower lip-S line (mm) 0 1 �2

*Pretreatment records at age 14 years 2 months; yPosttreatment re-cords at age 17 years 9 months.

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and elastomeric chains were used between the cen-tral or lateral incisor and the first premolars to im-prove the anterior movement. To maintain the spacefor prosthetic replacement, a compressed coil springwas also placed between the right central incisorand first premolar. Toward the end of the treat-ment, a 0.021 3 0.025-in stainless steel archwirewas inserted to establish optimal torque of the an-terior teeth. For the first premolars, accentuatedbuccal torque was used to the roots to simulate ca-nine prominence and give the required support tothe lips.

Accentuated lingual torque of the canine roots wasused to prevent too much prominence on both sides.Vertical elastics were used for the subsequent 2months to improve intercuspation of the teeth, andthen the appliances were removed. A circumferentialmaxillary retainer with a provisional right lateral inci-sor was used in the maxillary arch, whereas a bondedcanine-to-canine retainer was placed in the mandibu-lar arch.

TREATMENT RESULTS

The facial pattern was maintained (Fig 6), and thetreatment provided the following outcomes: Class I mo-lar relationships on both sides, maxillary first premolarsperforming the function of the canines in a Class I rela-tionship with the mandibular canines, and adequate

American Journal of Orthodontics and Dentofacial Orthoped

overbite and overjet. Lateral group function was estab-lished to prevent overload on the first premolars. Themaxillary and mandibular midlines remained mis-matched even at the end of treatment, with a 1.0-mmdeviation between them, and a space of 0.5 mm re-mained between the left lateral incisor and the first pre-molar; this was filled with composite resin after theretention period.

The lateral incisor space was restored witha bonded restoration, because the patient was too

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Fig 5. Periapical radiographs of the maxillary left side during treatment: A, while the first premolar wasbeing moved anteriorly; B, after opening of the space, the canine started the extrusion and occupieda better position in the arch.

Fig 6. Posttreatment facial and intraoral photographs.

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young to receive an implant immediately after ortho-dontic treatment (Fig 7). The posttreatment pano-ramic radiograph showed good parallelism of the

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roots and no root resorption. An accentuated rootcurvature of the left first premolar root could beseen (Fig 8). Cephalometrically, the patient had

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Fig 7. Posttreatment dental casts.

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a similar pattern as in the beginning of the treatmentas seen in the final cephalogram and the superimpo-sition (Figs 9 and 10). The 8-year posttreatment (6years postretention) records showed that the occlusionremained stable over the years, and that the condi-tions of the hard and soft tissues were also maintained(Fig 11).

Fig 8. Posttreatment radiograph.

DISCUSSION

Maxillary canine-premolar transposition is the mostfrequent type of transposition treated by orthodon-tists2,4-9 and is frequently associated with other dentalanomalies such as absence of teeth, as seen in thispatient.9,13,15 The etiologic factors for transpositionare variable; in this patient, the cause probably was theprolonged retention of the deciduous teeth, which isconsidered one of the most common causes fortranspositions.4,6,8,10

There are several treatment options available forcanine-premolar transpositions that might or mightnot involve extraction of permanent teeth.2,7,10,11,14

In the nonextraction treatment option with narrowdentoalveolar bone, it is preferable to maintainthe transposition, because attempts to restorethe normal tooth positions could lead to a pro-longed treatment period along with irreversible

American Journal of Orthodontics and Dentofacial Orthoped

consequences such as root resorption and gingivalrecession.1,7,13,16

The orthodontic treatment option of maintainingthe canine-premolar transposition has limitationswith respect to esthetic and functional rehabilita-tion.3,14,16 There are differences in size, shape, andcolor between the teeth involved, and this canoccasionally create esthetic problems with thepatient's smile.3,10,16 Furthermore, the gingivalmargin of the premolar is positioned more occlusallyrelative to the canine. Therefore, it could requiregingival recontouring after treatment, or extrusionof the canine and equilibration of the cusp. In our

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Fig 9. Posttreatment cephalogram and tracing.

Fig 10. Overall superimposition of the initial and finalcephalometric tracings on the sella-nasion line at sella.

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patient, the amount of equilibration would have beentoo extensive if the canines were extruded, so wepreferred gingival surgery. However, the patient andher parents believed that periodontal surgery wasnot necessary. Therefore, the gingival leveldiscrepancy remained and affected the overallesthetics.

In our patient, stripping was performed on the me-sial and distal surfaces of the canines to reduce themesiodistal width and to achieve a better functionalrelationship with the mandibular canine.17 Anotherimportant issue to be considered was the interferencebetween the palatal cusps of the transposed premolarand the mandibular canine that normally occurs intranspositions.16 However, in our patient, an accentu-ated buccal root torque was accomplished; conse-quently, lateral group function was established.Thereafter, no interference was observed betweenthe cusps at the end of treatment, and reshapingwas not necessary.

CONCLUSIONS

Such unusual treatment should be accompaniedby long-term follow-up to observe the stabilityand the condition of the occlusion. In our patient,the reevaluation conducted 8 years after treatmentand 6 years after retention showed an optimal func-tional occlusion with good stability of the toothpositions.

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This type of treatment is not the conventional proto-col for tooth transpositions. The appropriate treatmentshould be selected only after careful diagnosis, whichcan vary from patient to patient.

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Fig 11. Facial and intraoral photographs 8 years after the end of treatment (6 years postretention).

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REFERENCES

1. Bocchieri A, Braga G. Correction of a bilateral maxillary canine-first premolar transposition in the late mixed dentition. Am J Or-thod Dentofacial Orthop 2002;121:120-8.

2. Halazonetis DJ. Horizontally impacted maxillary premolar and bi-lateral canine transposition. Am J Orthod Dentofacial Orthop2009;135:380-9.

3. Maia FA, Maia NG. Unusual orthodontic correction of bilateralmaxillary canine-first premolar transposition. Angle Orthod2005;75:266-76.

4. Peck S, Peck L. Classification of maxillary tooth transpositions. AmJ Orthod Dentofacial Orthop 1995;107:505-17.

5. Peck S, Peck L, Kataja M. Concomitant occurrence of canine mal-position and tooth agenesis: evidence of orofacial genetic fields.Am J Orthod Dentofacial Orthop 2002;122:657-60.

6. Shapira Y, Kuftinec MM.Maxillary tooth transpositions: character-istic features and accompanying dental anomalies. Am J OrthodDentofacial Orthop 2001;119:127-34.

7. Babacan H, Kilic B, Bicakci A. Maxillary canine-first premolartransposition in the permanent dentition. Angle Orthod 2008;78:954-60.

8. Camilleri S. Maxillary canine anomalies and tooth agenesis. Eur JOrthod 2005;27:450-6.

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9. T€urkkahraman H, Sayin MO, Yilmaz HH. Maxillary canine transposi-tion to incisor site: a rare condition. Angle Orthod 2005;75:284-7.

10. Ciarlantini R, Melsen B. Maxillary tooth transposition: correct oraccept? Am J Orthod Dentofacial Orthop 2007;132:385-94.

11. Asensi JC. Mixed unilateral transposition of a maxillary canine,central incisor, and lateral incisor. Am J Orthod Dentofacial Orthop2010;137(Suppl):S141-53.

12. Parker WS. Transposed premolars, canines and lateral incisors. AmJ Orthod Dentofacial Orthop 1990;97:431-48.

13. Sato K, Yokozeki M, Takagi T, Moriyama K. An orthodontic case oftransposition of the upper right canine and first premolar. AngleOrthod 2002;72:275-8.

14. Kuroda S, Kuroda Y. Nonextraction treatment of upper canine-premolar transposition in an adult patient. Angle Orthod 2005;75:472-7.

15. Ruellas ACO, de Oliveira AM, PithonMM. Transposition of a canineto the extraction site of a dilaceratedmaxillary central incisor. Am JOrthod Dentofacial Orthop 2009;135(Suppl):S133-9.

16. Vitale C, Militi A, Portelli M, Cordasco G, Matarese G. Maxillarycanine-first premolar transposition in the permanent dentition. JClin Orthod 2009;43:517-23.

17. Bruno MB, Barraso Salom~ao M, Vilella Ode V, Mucha JN. A newspring for correction of maxillary canine-premolar transposition.J Clin Orthod 2008;42:303-7.

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