Factors influencing treatment duration of impacted maxillary canines.

Objectives: To determine factors associated with treatment duration in impacted maxillary canines (IMCs) using orthopantomography and cone beam computed tomography.

Materials and methods: Seventeen linear and angular measurements were evaluated using pretreatment radiographic images of 64 patients (83 IMCs). Treatment duration from surgical exposure until the canine appeared in the oral cavity and until achieving ideal alignment were recorded in months.

Results: Average treatment duration until appearance in the mouth was 14.61 ± 9.28 months and 26.98 ± 12.44 months until ideal alignment. Buccally impacted canines emerged in 6.56 ± 3.24 months and were ideally aligned in 19.44 ± 8.49 months in comparison with palatally positioned at 16.34 ± 9.19 and 28.91 ± 12.77 months, respectively. Canines localized around lateral incisors had shorter treatment times than those localized around central incisors. Canines that were inclined >30° to the sagittal medial line (SML) had significantly longer treatment time until initial appearance in the mouth (16.31 ± 9.32) compared with those inclined less (10.82 ± 8.92). Linear regression analyses demonstrated that these factors were predictors for both treatment duration until emergence and ideal alignment of the canine.

Conclusions: Treatment duration for IMCs is lengthy, particularly for palatally and mesially positioned canines and those with greater inclinations. Palatally located canines typically require twice as much time to emerge as those positioned buccally. Canines located nearer the central incisor area take twice as much time to emerge as those located in the lateral incisor area.