Buccal Bone Thickness of Maxillary Incisors Adjacent to Palatally Impacted Canines: A Split-Mouth CBCT Study

Background and Objectives: To compare the buccal bone thickness of adjacent maxillary incisors between the impacted and contralateral control sides in patients with unilateral palatally impacted canines (PICs) using a split-mouth cone-beam computed tomography (CBCT) design. Materials and Methods: CBCT records of 26 patients with a unilateral PIC (18 females, 8 males; mean age, 17.35 ± 4.58 years) were retrospectively analyzed. Buccal bone thickness was measured at five equally spaced levels from the root apex (Level A) to the buccal alveolar crest (Level E) for the central and lateral incisors. Alveolar crest height, incisor torque and rotation, follicular width, canine localization, canine-to-root proximity, and root resorption were also assessed. Results: The impacted side showed significantly reduced buccal bone thickness at the two most apical levels of the lateral incisor: Level A (-0.81 mm; p < 0.001) and Level B (-0.35 mm; p = 0.004). No side differences were observed at the remaining lateral incisor levels or at any central incisor level. In the orientation-adjusted sensitivity model accounting for incisor torque and rotation, Level A remained significant (-0.75 mm; p < 0.001), whereas Level B was attenuated (p > 0.005). Lateral incisors on the impacted side also showed reduced labial torque (-4.97°; p = 0.001) and greater mesiobuccal rotation (-12.23°; p < 0.001). Conclusions: PICs were associated with localized apical reduction in buccal bone thickness of the adjacent lateral incisor, accompanied by reduced labial torque and greater mesiobuccal rotation. Buccal bone thickness may represent a relevant consideration during CBCT-based treatment planning for PICs.