[Re-examination of the masticatory function of the first permanent molar].

The biting force of the first permanent molar, from children in the first grade of elementary school to adults in their seventies, was measured in 1959 and in 1987. Comparison between these two sets of data showed no significant difference in each age. The biting force of the second milk molar of kindergarteners aged from 4 to 5 years old, showed a decrease of nearly 5 kilograms on the average and in particular. The number of the children whose biting force was less than 15 kilograms increase. There was a negative correlation between the depth of the periodontal pocket of every kind of tooth and the biting force, and the average of the correlation coefficient was about minus 0.3. Especially, there was negative correlation between the depth of the periodontal pocket of the first permanent molar of patients in their forties and their biting force.