Abstract: The attrition on 1144 permanent teeth (except M3) on 70 crania was investigated. The results show that when M1 presents II scale of attrition, I1and I2, present III, I1, C°Il or III, the others II; when MI III, Il, I2 and C III, the others II; when M1 IV, the others III. Accoding to the results the author thinks that three factors, the form of the occlusal surface, the period of being used and dental function, effectively influence the dental wear. Generally speaking, the smaller the contacting area on the occlusal surface of teeth, the faster the wear; the longer the period of being used, the heavier the wear; the more important the function, the heavier the wear.
In addition, the attrition scale of the relative teeth on the maxilla and the mandible, and of bilateral symmetrical teeth were also observed and compared. The results show that most of the pairs present same attrition scale.

Key words: Dental wear