Development of difficulty index for management of impacted maxillary canine: A CBCT-based study

The aim of this study was to propose an Impacted Canine Treatment Difficulty Index using Cone-beam Computed Tomography (CBCT) imaging to assess difficulty anticipated during the alignment of impacted maxillary canine and further validate the index in clinical set up.

Pre-treatment CBCT of 15 patients with unilateral or bilateral impacted maxillary canine aged between 12 and 30 years were selected. All the following five factors were assessed on CBCT image: 1) angulation, 2) vertical position, 3) bucco-palatal position, 4) horizontal position and 5) rotation. Two orthodontists evaluated the pre-treatment CBCT for the selected five factors and allocated a total difficulty score. To validate the proposed difficulty index in clinical settings, a team of oral and maxillofacial surgeons were included in the study to grade the difficulty encountered during surgical procedure.

The distribution of difficulty score recorded by observer 1 was significantly associated with the difficulty score recorded by observer 2 (P-value < 0.001), with relatively higher level of linearly weighted Cohen's kappa value of 0.610. The distribution of difficulty score recorded by oral and maxillofacial surgeon was significantly associated with the difficulty score recorded by observer 1 (P-value < 0.01), with relatively higher level of linearly weighted Cohen's kappa value of 0.667. The distribution of difficulty score recorded by orthodontist was significantly associated with the difficulty score recorded by observer 1 (P-value < 0.001), with relatively higher linearly weighted Cohen's kappa value of 0.819.

Impacted Canine Treatment Difficulty Index using CBCT imaging could be used to assess the difficulty that would be anticipated during the alignment of impacted maxillary cuspid.