Oral and dental diseases among 1, 315 employees of a financial institution in Shiga Prefecture were examined by dentists. Each number of F-teeth, D-teeth, M-teeth and DMF-teeth was counted. The influences of such factors as sex, age, periodontal disease, calculus, malocclusion, and tooth brushing were determined quantitatively by the quantification analysis I.
The average number of teeth of each type per person was as follows: F-teeth 6.45 for males and 8.57 for females, D-teeth 3.29 and 2.41, M-teeth 1.37 and 1.49, and DMF-teeth (DMFT) 11.47 and 12.48, respectively. The number of F-teeth was greatly influeced by the place of employment, sex, and age. Yokaichi and Imazu-Kinomoto showed an increase in the number of F-teeth. The average number of F-teeth per person decreased above 40 years of age in males, and above 50 years of age in females.
The greatest influence on the number of D-teeth was the place of employment. Imazu-Kinomoto showed an increase in the number of D-teeth, and Minakuchi and Yokaichi showed a decrease. Age had the strongest influence on the number of M-teeth. Both the extent of increasing the number of M-teeth, and the average number of M-teeth per person bacame larger with age. Above 50 years of age, the average number of M-teeth per person remarkably increased. The average number of DMF-teeth per person was also greatly influenced by age. The DMFT plotted by age showed a J-curve for males and a reversed L-curve for females.
Periodontal disease, calculus, and malocclusion had scarcely influenced on the number of F-, D-, M-, and DMF-teeth. However, the influence of the tooth brushing on the number of D-teeth and M-teeth showed a linear correlation.
