Abstract: Objective To study the risk factors of wedge-shaped defects. Methods Thirty patients with total 420 maxillary teeth were selected. And the Teetester occlusal analysis system was employed to record premature contact teeth, disocclusion time (DT) and occlusal force through which the risk factors were thus statistically revealed. Results Among the maxillary teeth, premolars occupied 46.49%, which illustrates that the maxillary premolar region is the susceptible area of wedge-shaped defects. Among 64 premature contact teeth, 42 were defected teeth, according to Chi-square statistics, Pearsonχ2=25.732, P<0.001, OR=4.0, 95% Confidence interval (2.282~7.015), which illustrates that premature contact is a risk factor. Moreover, among 26 over disocclusion time teeth, 17 were defected teeth, according to Chi-square statistics, Pearsonχ2=9.285, P<0.05, OR=3.427, 95% Confidence interval (1.489~7.890), which illustrates that disocclusion time is another risk factor. The difference of occlusal force between 41 defected teeth and normal teeth were obvious (P<0.05). And the difference of occlusal force between 43 pairs of deeper defected teeth and lighter defected teeth were obvious (P<0.05) too. Conclusion The maxillary premolar region is the susceptible area of wedge-shaped defects. Premature contact teeth, disocclusion time, and occlusal force are risk factors.

Key words: Wedge-shaped defects, Premature contact, Disocclusion time