Alveolar Bone Morphology Analysis Of Upper Central Incisor In Class Ⅱ Division 1 And Division 2 By Cone-Beam Computed Tomography

Objective:We evaluate the alveolar bone morphology of adult upper central incisor between Angle Class Ⅱ division 1,division 2 malocclusion and normal occlusion by CBCT,which provided reference for orthodontic clinical tooth movement.Methods:The sample consisted of 20 normal occlusion people and 40 patients with Angle Class Ⅱ malocclusion(20 division 1 malocclusion patients and 20 division 2malocclusion patients,18~35 years old).All subjects were scanned and reconstructed into a three-dimensional(3D)structure using a micro-CT system.The Thickness of labial and lingual alveolar bone in apical region of upper central incisor,the height of labial and lingual alveolar bone in upper central incisor and inclination of upper central incisor were measured by CBCT.All statistical analyses were performed by the Statistical Package for the Social Sciences version 22.0.Results:1.The thickness of labial alveolar bone in the apical region: the thickness of the alveolar bone in division 2 of class II was smaller than that of class II division 1 and normal occlusion.The thickness of lingual alveolar bone in apical region: class II division 2 > normal occlusion > class II division 1;The total thickness of alveolar bone in the apical region: class II division 1 was smaller than the other two groups.2.The attachment height of labial alveolar bone of class II was greater than that of normal occlusion,attachment height of lingual alveolar bone: class II division 1 > class II division 2 > normal occlusion.3.The correlations between the inclination of upper central incisor and the thickness of the alveolar bone were statistically significant.With the increase of upper central incisor inclination of class II,the thickness of labial alveolar bone in apical region increases,lingual alveolar bone thickness and the total alveolar bone thickness decreases.The attachment height of the alveolar bone of the upper central incisor was not related to the inclination of the upper central incisor.Conclusion:There were differences in the morphology of alveolar bone between Class Ⅱdivision 1,Class Ⅱ division 2 and the normal occlusion.The surrounding alveolar structures was closely related to different types of malocclusion and the inclination of teeth.The morphology of alveolar bone should be evaluated before orthodontic treatment,on the basis of the results of this study,guidelines for morphology of alveolar bone can be suggested on orthodontic treatment to minimize damage of the periodontal injury.