Impaction of the maxillary permanent canine has an

CLINICIAN S CORNER Failure after closed traction of an unerupted maxillary permanent canine: Diagnosis and treatment planning Giulio Alessandri Bonetti, a Serena Incerti Parenti, b Giuseppe Daprile, c and Marco Montevecchi d Bologna and Ferrara, Italy This report describes the treatment of a 13-year-old girl with unerupted maxillary permanent canines. It illustrates how recognizing an unexpected problem influenced the decision-making process. Despite 6 months of closederuption traction, the left canine had not erupted. However, the neighboring teeth were intruded, suggesting a diagnosis of canine ankylosis. When the site was surgically reopened, the wire chain used for the orthodontic traction appeared to be osseointegrated. It was renewed, and traction was applied for another 16 months, and the tooth was successfully brought into the arch. Bone tissue passing through the chain might have prevented forced eruption. In young patients with unerupted maxillary permanent canines, failure of closed traction can be attributed to ankylosis, and this accounts for tooth extraction as the treatment of choice. However, this clinical report suggests that additional measures might be warranted before the definitive diagnosis of ankylosis can be made and the tooth extracted. (Am J Orthod Dentofacial Orthop 2011;140:121-5) Impaction of the maxillary permanent canine has an estimated prevalence of 1.7% in the general population, but the incidence might be higher in those who have been referred to orthodontists. 1-3 This might be explained by the tooth being deflected from its normal eruptive path and becoming either labially, centrally, or, more often, palatally impacted. 4 With an adequate clinical and radiographic diagnosis in the mixed dentition stage, 4-13 palatally or centrally displaced maxillary permanent canines have been shown to frequently correct with early extraction of the deciduous canines, 9,14-17 or concomitant extraction of the deciduous canines and first molars. 18,19 This reduces the need for orthodontic appliances and also the incidence of resorption on the adjacent incisor roots, a Assistant professor, Department of Orthodontics, School of Dentistry, University b Postgraduate student, Department of Orthodontics, University of Ferrara, Italy. c Visiting professor, Department of Periodontology, School of Dentistry, University d Assistant professor, Department of Periodontology, School of Dentistry, University The authors report no commercial, proprietary, or financial interest in the products or companies described in this article. Reprint requests to: Giulio Alessandri Bonetti, Department of Orthodontics, Alma Mater Studiorum, University of Bologna, Via San Vitale 59, 40125 Bologna, Italy; e-mail, giulio.alessandri@unibo.it. Submitted, August 2009; revised and accepted, September 2009. 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2009.09.025 which might occur in nearly 50% of patients with ectopic canines. 1,20,21 If the diagnosis is made at a later stage (after 12-13 years of age), 21 surgical exposure followed by traction of the tooth with orthodontic forces is often required. 3,14,22-24 Failures to respond to direct orthodontic extrusive traction in the absence of any mechanical obstruction of the eruption pathway (caused by odontomas, odontogenic tumors, or supernumerary teeth) have been generally attributed to an unhealthy periodontal membrane (ie, tooth ankylosis). 3,14,25 The purpose of this clinical report was to describe an unexpected problem encountered during the treatment of an unerupted maxillary permanent canine, the recognition of which enabled a change in the diagnosis and, consequently, in the decision-making process, thus allowing a successful clinical outcome. CASE REPORT A 13-year-old girl was referred for orthodontic consultation. The clinical examination showed an Angle Class I occlusion with moderate mandibular anterior crowding and persistence of both the maxillary right and left deciduous canines (Fig 1). The patient s medical and dental histories were unremarkable, and no family history of maxillary canine impactions was reported. No maxillary permanent canine bulges could be palpated. There was distal-palatal rotation of the maxillary 121

122 Alessandri Bonetti et al Fig 1. Intraoral frontal and lateral views before treatment. left lateral incisor, possibly due to a displaced permanent canine lying on its root (Fig 1). Panoramic and periapical radiographs confirmed the presence of both unerupted maxillary permanent canines; the right canine was centrally located in a vertical position, and the left canine was palatally displaced and inclined mesially, high in the alveolar process, with its crown overlapping the root of the adjacent lateral incisor (Fig 2, A). The treatment plan consisting of a surgicalorthodontic approach was explained to the patient and her parents, and their informed consent was obtained. The maxillary deciduous canines were extracted, both maxillary permanent canines were surgically exposed under local anesthesia, and an orthodontic buttonhole connected to a wire chain was bonded directly onto them. Initially, orthodontic traction was activated on the right canine only to prevent excessive vertical and anteroposterior anchorage loss on the maxillary permanent incisors. Furthermore, due to a relatively more feasible position, this tooth should have been brought into the arch in a shorter period of time compared with the left canine. The tooth successfully erupted during 2 months of orthodontic traction, and a bracket was bonded on its buccal surface. Once fully aligned in the dental arch, greater anchorage had been obtained for orthodontic extrusive traction to be activated on the left side. After 6 months of orthodontic traction by the closederuption approach, clinical and radiographic analysis showed no movement of the left permanent canine associated with an intrusive movement of the adjacent teeth (Figs 2, B, and 3), suggesting a diagnosis of ankylosis. A second surgery was thus scheduled to remove the unerupted tooth. At reentry, the canine showed mobility, and the direction of orthodontic traction was correct, but the wire chain appeared to be osseointegrated (Fig 4). After that finding, the surgeon (G.D.) and the orthodontist (G.A.B.) decided not to extract the canine, but to renew the wire chain and reactivate the orthodontic Fig 2. Panoramic radiographs: A, before treatment; B, after 6 months of active traction, the maxillary left canine had not moved, but the neighboring teeth intruded, and their roots began to converge. traction on the left side. The evidence of initial tooth movement proved that the diagnosis of ankylosis was incorrect. For this reason, it was decided to continue the treatment, and, after a further 16 months of active orthodontic traction, the left permanent canine was successfully aligned in the dental arch (Figs 5 and 6). DISCUSSION When a combined surgical-orthodontic approach is undertaken, the patient should be informed of the possibility of failure, a factor that, together with the July 2011 Vol 140 Issue 1 American Journal of Orthodontics and Dentofacial Orthopedics

Alessandri Bonetti et al 123 Fig 3. Intraoral photographs after 6 months of active traction. Fig 4. Osseointegration of the wire chain was found when the site was reopened. Arrows indicate bone tissue passing through the chain. increased treatment time, must be considered in the decision-making process. 25,26 A successful treatment outcome might not be warranted before treatment by either clinical or radiographic diagnostic criteria. 27 Rarely, the diagnosis of ankylosis can be made before treatment, if the periodontal ligament space is radiographically discontinuous or not evident. 28 Now, however, such a radiographic assessment might not be possible by either conventional radiographs (periapical intraoral or panoramic radiographs), computed tomography, or magnetic resonance imaging, because the pericoronal space seen radiographically might represent scar tissue instead of a normal follicle. 29 Only the detection of any eruptive movements occurring after the application of an orthodontic extrusive force will indicate a good prognosis. 24,27 Movement of impacted teeth by closed traction could be prevented, in the absence of any mechanical obstruction, by tooth ankylosis, scar tissue blocking the wire chain, or incorrect direction of the orthodontic traction. 3,14,25 In this clinical report, an initial diagnosis of ankylosis was made, since an unerupted maxillary permanent canine did not move after orthodontic traction. At surgical reentry to extract the tooth, the initial diagnosis was changed because of the osseointegration of the wire chain and the tooth s mobility. The outcome of this clinical report indicates that, if a proper differential diagnosis among factors associated with failure after closed traction had not been made, a maxillary permanent canine with a healthy periodontal ligament would have been extracted, thus forcing a young girl with an otherwise good dental alignment to undergo a surgical extraction and a subsequent single-tooth replacement by implant or prosthetic therapy, or, otherwise, an orthodontic therapy to close the space of the canine after compensatory extractions of 3 premolars. CONCLUSIONS In young patients with unerupted maxillary permanent canines, it is only after a surgical reentry and a negative finding relative to bone or scar tissue passing through the chain (if the orthodontic traction was correctly directed) that a definite clinical diagnosis of ankylosis can be made and the tooth extracted. In the patient in this report, the 2-month period before orthodontic traction could perhaps be hypothesized as a possible causative factor for the osseointegration of the wire chain. However, no other studies are currently available to support this potential association. American Journal of Orthodontics and Dentofacial Orthopedics July 2011 Vol 140 Issue 1

124 Alessandri Bonetti et al Fig 5. Intraoral photographs at the end of treatment. Fig 6. Panoramic radiograph at the end of orthodontic treatment. The neighboring tooth shows an apparent reduction in root length compared with the initial panoramic radiograph. This can be attributed to a slight apical root resorption, possibly due to the preexisting permanent canine position but, also, to increased buccal inclination of the maxillary incisors. REFERENCES 1. Kurol J. Early treatment of tooth-eruption disturbances. Am J Orthod Dentofacial Orthop 2002;121:588-91. 2. McDonald F, Yap WL. The surgical exposure and application of direct traction of unerupted teeth. Am J Orthod 1986;89:331-40. 3. Zuccati G, Ghobadlu J, Nieri M, Clauser C. Factors associated with the duration of forced eruption of impacted maxillary canines: a retrospective study. Am J Orthod Dentofacial Orthop 2006; 130:349-56. 4. Jacobs SG. Localization of the unerupted maxillary canine: how to and when to. Am J Orthod Dentofacial Orthop 1999;115:314-22. 5. Shapira Y, Kuftinec MM. Early diagnosis and interception of potential maxillary canine impaction. J Am Dent Assoc 1998;129: 1450-4. 6. Warford JH Jr, Grandhi RK, Tira DE. Prediction of maxillary canine impaction using sectors and angular measurement. Am J Orthod Dentofacial Orthop 2003;124:651-5. 7. McSherry PF. The ectopic maxillary canine: a review. Br J Orthod 1998;25:209-16. 8. Ericson S, Kurol J. Radiographic examination of ectopically erupting maxillary canines. Am J Orthod Dentofacial Orthop 1987;91: 483-92. 9. Power SM, Short MB. An investigation into the response of palatally displaced canines to the removal of deciduous canines and an assessment of factors contributing to favourable eruption. Br J Orthod 1993;20:215-23. 10. Lindauer SJ, Rubenstein LK, Hang WM, Andersen WC, Isaacson RJ. Canine impaction identified early with panoramic radiographs. J Am Dent Assoc 1992;123:91-2, 95-7. 11. Ericson S, Kurol J. Longitudinal study and analysis of clinical supervision of maxillary canine eruption. Community Dent Oral Epidemiol 1986;14:172-6. 12. Ericson S, Kurol J. Radiographic assessment of maxillary canine eruption in children with clinical signs of eruption disturbance. Eur J Orthod 1986;8:133-40. 13. Alessandri Bonetti G, Zanarini M, Danesi M, Incerti Parenti S, Gatto MR. Percentiles relative to maxillary permanent canines inclination by age: a radiologic study. Am J Orthod Dentofacial Orthop 2009;136:486:e1-6. 14. Kurol J, Ericson S, Andreasen JO. The impacted maxillary canine. In: Andreasen JO, Petersen JK, Laskin DM, editors. Textbook and colour atlas of tooth impactions: diagnosis, treatment, prevention. Copenhagen, Denmark: Munskgaard; 1997. p. 124-64. 15. Leonardi M, Armi P, Franchi L, Baccetti T. Two interceptive approaches to palatally displaced canines: a prospective longitudinal study. Angle Orthod 2004;74:581-6. 16. Baccetti T, Leonardi M, Armi P. A randomized clinical study of two interceptive approaches to palatally displaced canines. Eur J Orthod 2008;30:381-5. 17. Ericson S, Kurol J. Early treatment of palatally erupting maxillary canines by extraction of the primary canines. Eur J Orthod 1988; 10:283-95. 18. Alessandri Bonetti G, Incerti Parenti S, Zanarini M, Marini I. Double vs single primary teeth extraction approach as prevention of permanent maxillary canines ectopic eruption. Pediatr Dent 2010; 32:407-12. 19. Alessandri Bonetti G, Zanarini M, Incerti Parenti S, Marini I, Gatto MR. Preventive treatment of ectopically erupting maxillary permanent canines by extraction of deciduous canines and first molars: a randomized clinical trial. Am J Orthod Dentofacial Orthop 2011;139:316-23. 20. Ericson S, Kurol J. Resorption of incisors after ectopic eruption of maxillary canines. A CT study. Angle Orthod 2000;70:415-23. 21. Bjerklin K, Ericson S. How a computerized tomography examination changed the treatment plans of 80 children with retained and ectopically positioned maxillary canines. Angle Orthod 2006;76:43-51. 22. Zuccati G. Bilaterally impacted maxillary canines: a case report in an adult. Eur J Orthod 1994;16:325-8. 23. Schmidt AD, Kokich VG. Periodontal response to early uncovering, autonomous eruption, and orthodontic alignment of palatally impacted maxillary canines. Am J Orthod Dentofacial Orthop 2007; 131:449-55. 24. Bishara SE. Impacted maxillary canines: a review. Am J Orthod Dentofacial Orthop 1992;101:159-71. July 2011 Vol 140 Issue 1 American Journal of Orthodontics and Dentofacial Orthopedics

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