Relationship Between the Initial Position of Palatally Displaced Canines and Treatment Duration

Abstract

This prospective study aimed to assess the positional features of palatally displaced maxillary canines (PDCs), their relationship with both cephalometric and dental cast measurements and treatment duration. Pretreatment panoramic and lateral cephalometric radiographs and dental casts of 46 patients (23 patients with uni/bilateral PDC and 23 patients with Class I malocclusion) were collected. The mesial inclination of the permanent canine to the midline (α angle), the distance from the cusp tip of the permanent canine to the occlusal line (d distance), and the mesial position of the crown of the displaced canine (sector) were measured on the panoramic radiographs. SNA°, SNB°, ANB°, SN-GoGn°, SN-PP°, and PP-MP° angles and sagittal inclinations of the PDCs’ (C-PP°) were measured on cephalometric radiographs. Arch length discrepancies and transversal arch measurements were also performed. The Student’s t-test, Mann-Whitney U test and Kruskal-Wallis test were used to compare variables that were not normally distributed while ANOVA was used for the normally distributed data.  The arch widths were similar between the groups while crowding was significantly greater in the PDC group. A negative correlation was found between the α angle and vertical plane angle (SN-GoGn°). Treatment duration was positively correlated with α angle and d distance but there was no relationship with the sagittal angulation of the PDC to the palatal plane (C-PP°) and the treatment duration. Treatment duration can be expected to be longer with every increase in the angle of the PDC to the midline and distance from the occlusal plane.