Statement of problem. Although all the processes of loss of hard tissue are important, attrition on the occlusal surfaces commands our attention. Purpose of study. The enamel wear rate of 18 young adults over 2 consecutive years was measured independently by volume loss and mean depth loss. Any significant differences in tooth wear resulting from gender and a clinical diagnosis of bruxism were identified. Material and methods. A strict protocol for dental impressions provided epoxy models, which were digitized with a null point contact stylus. AnSur software provided a complete morphologic description of changes in the wear facets. Results. The mean loss for all teeth measured was 0.04 mm 3 by volume and 10.7 μm by depth for the first year. Conclusions. These numbers were approximately doubled at 2 years of cumulative wear. (J Prosthet Dent 1997;77:313-20.).