Abstract: Objective: To measure the alveolar bone thickness at different sites of upper incisor in adult patients of Angle Ⅱ with CBCT. Methods: According to inclusion criteria, 150 adult patients were included: 50 cases in Angle Ⅱ¹ group, 50 cases in Angle Ⅱ² group, and 50 cases in normal occlusion group. The acquired CBCT image data were imported into the Invivo5.0 image processing software for 3D reconstruction. The thickness of alveolar bone on the maxillary labial side on the sagittal plane of the tooth body was measured, and the percentage of labial alveolar bone thickness to the total alveolar bone thickness was calculated. Results: 1) The turn of thickness in labial alveolar bone at different sites was: individual normal occlusion group, AngleⅡ¹ group, and Angle Ⅱ² group. However, in the root tip, the turn was: Angle Ⅱ¹ group, individual normal occlusion group, and Angle Ⅱ². 2) The turn of thickness of labial alveolar bone was: apical region, middle of the root, and the neck of the root (P<0.05). Conclusion: The labial alveolar bone thickness in upper incisors was related to the type of malocclusion. Except apical area, the thickness of labial alveolar bone of central incisor was less than 2 mm. The percentage of labial alveolar bone thickness to total alveolar bone thickness was less than 20%.

Key words: Adult Angle Ⅱ malocclusion, Upper incisors, Alveolar bone thickness, CBCT