Surgically assisted orthodontic alignment of impacted maxillary canines: A retrospective analysis of functional and esthetic outcomes and risk factors for failure

Introduction The initial position of an impacted maxillary canine might influence the outcome of surgically assisted exposure and orthodontic alignment. Therefore, the purpose of this study was to evaluate existing correlations between the initial position of the maxillary canine and the outcomes of treatment. Methods A retrospective cohort study was designed, containing data of 132 patients (47 males, 106 females; median age at the date of surgical exposure 14 ± 4.6 years; range, 10-39 years) with a total of 153 impacted maxillary canines. The sample was based on orthodontic referrals over 4 years at the Department of Oral and Maxillofacial Surgery, Rijnstate Hospital, Arnhem, the Netherlands. The esthetic outcome, treatment duration, and success and failure rate were investigated in relation to the initial position of the maxillary canine as assessed on pretreatment panoramic radiographs (vertical and anteroposterior sector position and angulation of the canine [α-angle]). The esthetic evaluation was performed using the Maxillary Canine Aesthetic Index. The success of treatment was defined as achieving a fully functional eruption of the canine, with an esthetically excellent result, without the need for reinterventions. Failure of treatment was defined as the need for reintervention or removal of the canine. Results In 96% of the impacted canines, a successful orthodontically assisted eruption was achieved. Age, vertical distance, and angulation are predictors of the esthetic outcome of impacted canines after treatment. Age, bilateral impaction, sector, vertical distance, and angulation are predictors of treatment duration. Age, vertical distance, and buccolingual position are predictors of the need for reintervention. Conclusions Pretreatment radiographic variables can help in predicting the outcome and treatment duration of surgically exposed maxillary impacted canines.