Year : 2010 | Volume
: 28 | Issue : 1 | Page : 38--41
Management of an impacted and transposed maxillary canine
A Deepti, R Rayen, J Jeevarathan, MS Muthu, Prabhu V Rathna
Department of Pediatric Dentistry, Meenakshi Ammal Dental College, Maduravoyal, Chennai, India
Department of Pediatric Dentistry, Meenakshi Ammal Dental College, Alapakkam Main Road, Maduravoyal, Chennai
Maxillary canine-lateral incisor transposition is a relatively rare anomaly, with both dental and facial esthetic implications. This is a case report of a maxillary canine-lateral incisor transposition that was successfully treated by surgical-orthodontic treatment followed by esthetic reshaping of the involved teeth.
|How to cite this article:|
Deepti A, Rayen R, Jeevarathan J, Muthu M S, Rathna PV. Management of an impacted and transposed maxillary canine.J Indian Soc Pedod Prev Dent 2010;28:38-41
|How to cite this URL:|
Deepti A, Rayen R, Jeevarathan J, Muthu M S, Rathna PV. Management of an impacted and transposed maxillary canine. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2023 Jan 27 ];28:38-41
Available from: http://www.jisppd.com/text.asp?2010/28/1/38/60477
Transposition is a relatively rare dental anomaly, characterized by an interchange in the position of 2 adjacent permanent teeth on the same side of the dental arch.  It is identified as complete transposition when the crowns and the roots of the involved teeth exchange places in the dental arch; and incomplete transposition when the crowns are transposed but the roots remain in their normal positions.  The canine is one of the most commonly involved teeth in the transposition phenomenon. , Tooth transposition generally occurs in the maxilla and is often associated with other dental anomalies, such as agenesis, retained primary canine and peg-shaped or small maxillary lateral incisors. , Transpositions affect both sexes, but female patients have been reported to outnumber male patients in the prevalence of this anomaly.  The condition may occur both unilaterally or bilaterally, but a greater incidence of unilateral cases has been reported. Left side dominance has also been reported. ,, Some studies ,,,, have reported the prevalence of transposition as 0.4%. The etiology of transposition is still obscure. However, transposition of tooth buds at anlage stage; migration of a tooth during eruption; heredity; retained deciduous teeth; and trauma have been proposed as possible etiological factors. ,,
The canine shows the highest incidence of transposition with the first premolar, ,, less often with the lateral incisor, ,,,, rarely with the central incisor  and extremely rarely with the second premolar  or first molar.  Transposition in the maxilla is always a result of displacement and ectopic eruption of the maxillary canine, whereas transposition in the mandible is typically a result of distal migration of the mandibular lateral incisor. Conversely, the mandibular canine develops and erupts in its relatively normal anatomic position. 
Transpositions were classified according to Peck and Peck as 
Maxillary canine-first premolar (Mx.C.P1)Maxillary canine-lateral incisor (Mx.C.I2)Maxillary canine to first molar site (Mx.C to M1)Maxillary lateral incisor-central incisor (Mx.I2.I1)Maxillary canine to central incisor site (Mx.C to I1)Mandibular lateral incisor-canine (Mnd.I2.C)Impacted teeth are those with a delayed eruption time or that are not expected to erupt completely, based on clinical and radiographic assessment.  Permanent maxillary canines are the second most frequently impacted teeth. The prevalence of their impaction is 1%-2% in the general population, and palatal impaction is most frequent (85%). , Common causes of canine impaction can be local or genetic. The local factors include congenitally missing lateral incisors, supernumerary teeth, odontomas, transposition of teeth and other mechanical determinants that all interfere with the path of eruption of the canine.  Maxillary canines develop high in the maxilla, are among the last teeth to develop and travel a long path before they erupt into the dental arch.  These factors increase the potential for mechanical disturbances resulting in displacement and thus, impaction. Methods of diagnosis that may allow for early detection and prevention should include a family history, visual and tactile examinations by the age of 9 to 10 years and a thorough radiographic assessment. Because there is a high probability that palatally impacted maxillary canines may occur with other dental anomalies, the clinician should be alert to this possibility. 
This is a rare case report of an impacted and transposed permanent maxillary canine with lateral incisor (Mx.C.I2). A PUBMED search revealed a single similar case of bilateral maxillary canine impaction with incomplete lateral incisor transposition in an adult. The case was treated by relocating the canines in their correct position in the arch. The impacted teeth were driven through the sockets of the extracted primary teeth.  In this case, as it was a complete transposition, the treatment plan included surgical exposure and orthodontic repositioning of the canine in its transposed position, followed by esthetic reshaping to make it look like the contralateral lateral incisor.
A 12-year-old female patient reported to the Department of Pediatric Dentistry with the chief complaint of missing upper front tooth. Past medical and dental history was noncontributory. Clinical examination revealed permanent dentition with missing right maxillary permanent canine [Figure 1]. The contralateral canine was present, and the permanent laterals were smaller in size. A palatal bulge was present in relation to the unerupted canine. The girl had a class I molar relationship. Radiographic examination revealed a mature impacted right maxillary permanent canine which was in complete transposition with the permanent lateral incisor [Figure 2]. The treatment plan consisted of creating space for the canine, followed by surgical exposure and orthodontic alignment and reshaping of the canine.
A fixed orthodontic appliance along with e-chain was placed to gain space for the canine [Figure 3]. Once the space was gained, the canine was exposed surgically by raising a palatal flap. A lingual button was bonded on the exposed palatal surface of the canine, and the flap was sutured back over the crown leaving a 0.010-inch ligature wire fixed over the button and passing through the mucosa to apply orthodontic traction [Figure 4]. Once the canine was considerably visible, the lingual button was replaced with a Begg bracket, and elastic traction was used to align the teeth. Periodic radiographs were taken to monitor the movement of the impacted and transposed canine. After 13 months of treatment, the canine was orthodontically aligned in its transposed position [Figure 5] and the brackets were debonded. Following shade matching (A2 shade, 3M ESPE), the transposed canine and lateral incisor were recontoured and reshaped to look like the contralateral lateral incisor and the canine [Figure 6].
The maxillary canines are important keystones in the dental arch, both for good esthetics and normal masticatory function. Any bony obstruction, insufficient bone development, crowding or resistance of the neighboring teeth such as a retained primary canine, may deflect a permanent canine from its eruptive path.  When deflected lingually, it may become palatally impacted, lying in an oblique or horizontal position. It may however be displaced mesially and become transposed with lateral incisor, or distally and become transposed with premolar.  In this case, the canine was palatally impacted as well as transposed with the lateral incisor mesially. The possible reason for this can be transposition of the tooth bud during the anlage stage, which in turn resulted in the impaction of the canine.
As stated by Shafer,  leaving the impacted canines may result in serious sequelae: Displacement of the adjacent teeth and shortening of the dental arch, internal resorption, formation of follicular cysts, external resorption of the canine and adjacent teeth, recurrent infections especially when the tooth is partially erupted, recurrent pain, or combinations of the above. To avoid any such sequelae, decision was made to treat the impacted canine by surgical-orthodontic treatment.
Early diagnosis and detection of a developing transposition is based on clinical examination followed by complete radiographic survey. When detected early enough, interceptive treatment may resolve the developing malocclusion. This may be especially true for the displaced mandibular lateral incisors.  When incipient transposition is detected early enough, interceptive treatment should be initiated to remove the retained mandibular primary teeth and guide the ectopic mandibular lateral incisors to their normal places in the arch.  Similarly the interceptive treatment in case of an impacted canine is extraction of the primary canine. However, extraction of the primary cuspid does not guarantee correction or elimination of the problem. If there is no radiographic evidence of improvement 1 year after treatment, more aggressive treatment, such as surgical exposure and orthodontic eruption, is indicated. 
Treatment options in case of transposition include alignment of the involved teeth in their transposed positions, extraction of one of the transposed teeth, or a complete orthodontic correction to their normal anatomic positions. [ 1] In incomplete transpositions, where the crowns are transposed but the roots are in normal position, uprighting and rotating the involved teeth is the procedure undertaken to place them in normal alignment provided sufficient space is available in the arch.  When a transposition is complete, repositioning the teeth in their normal positions is complex and may be damaging to the teeth or supporting structures. Multiple factors such as the position of the root apices, dental and facial esthetics, acceptable occlusion, patient age, motivation, expected compliance and the extra length of treatment time should be carefully considered in deciding upon treatment options. Hence in the case of complete transpositions, alignment of the teeth in their transposed positions with reshaping of their incisal surfaces will give an acceptable esthetic result. In this case the transposition was complete, and hence we decided to align the teeth orthodontically in the transposed positions and then reshape them for the purpose of esthetics. The patient and her parents were extremely satisfied with the results.
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