- Volume 6 Issue 1
The author collected 146 men's stone models and 175 women;s stone models over the age of twenties, and studied area ratio of attrition of molars. Area ratio of attrition = (area of attrition / area of occlusal surface)*100(%) All data were analyzed by means of statistical method, and following results were obtained. 1. There was correlation between age and area ratio of attrition, that is, area ratio of attrition was increased with aging process. 2. Regression equtions and coefficients of correlation showed a significant meaning. 3. Generally, upper teeth showed higher tendency of area ratio of attrition, being compared with lowers. 4. Being compared with male and female, there was no uniform difference.