Abstract: Objective: To investigate the risk factors with dehiscences and fenestrations of upper lateral incisors and canines using CBCT. Methods: CBCT images of untreated patients in China Medical University Hospital of Stomatology from 2014 to 2016 were selected. Forty-four upper lateral incisors and 43 upper canines with dehiscences or fenestrations were selected as test group, and 43 upper lateral incisors and 41 upper canines without alveolar defects were selected as control group. Results: There were significant differences on the tooth axis, the angle between tooth axis and alveolar bone axis, curvature angle of alveolar bone, alveolar bone width, differences between the root diameter and alveolar bone width, tooth position in the alveolar bone (P<0.05). There was no difference on the length of root and the distance from the root apical to the deepest point on the buccal bone (P＞0.05). Conclusion: Tooth lingual inclination, larger angle between tooth axis and alveolar bone axis, thin alveolar, more curved alveolar buccal bone, and tooth position deviated from the alveolar bone (lateral or lingual) are risk factors of dehiscences and fenestrations in maxillary lateral incisors and canines.

Key words: CBCT, Fenestration, Dehiscence