A STUDY ON THE TEETH SHAPE AND POSITION OF NORMAL OCCLUSION IN CHINESE

Objective:To provide the basic data for the straight wire appliance which is suitable to Chinese. Methods:The modern three dimensional measurement instrument was used for the measurements of the six keys to normal occlusion in 67 Chinese models with the normal occlusion. Results:Compared with the measurements of American normal occlusion by Andrews, our data showed that the characteristics of teeth shape and position of Chinese with the normal occlusion were as follows: Crown inclinations of upper incisors, upper canines and lower canines were large. Crown angulations of incisors and canines were small. Differences of crown facial prominence between canines and lateral incisors were large. So were the differences of crown facial prominence between first molars and second premolars. However, differences of crown facial prominence between upper central and lateral incisors were small. Lower first molars of Chinese with the normal occlusion had negative offset angles. Conclusion: Chinese with the normal occlusion have their own race characteristics. The straight wire appliance suitable to Chinese should be used for Chinese patients.