OBJECTIVETo perform the quantitative study of tooth occlusal surface wear by a noncontact 3D image survey system.

METHODSThirty-two old people's complete dental casts in five years which had normal occlusion were studied. The same way was used to determine the individual reference surface, and the range of the maxillary first molar occlusal surface was delimited by the unite regulation. Then the quantity of wear in five years and wear rate of maxillary first molar occlusal surface were measured by the noncontact 3D image survey system.

RESULTSWear of maxillary first molar occlusal surfaces was as follows: the mean height loss was 0.293 mm in five years and the mean wear rate was 0.059 mm/year; the mean volume loss was 97.881 mm(3) in five years and the mean wear rate was 19.576 mm(3)/year.

CONCLUSIONSUnder the necessary conditions, the noncontact 3D image survey system is an effective method to measure the wear of dental occlusal surface, but some set-up conditions need to be improved further.