Abstract
In 432 subjects, analysis was made of erupted teeth according to the kinds of teeth and according to the groups of teeth and of the carious conditions at Hirogamimura, Kitauonuma-gun, Niigata Prefecture during a 9-year-period from 1981 to 1989. In addition, examination was made of the effectiveness of the results of evaruation based on the caries activity test (Cariostat®) at the start of the reuption of the permanent teeth as a mean of prediction of carious conditions kinds of teeth and the groups of teeth. The results were as follows:
1) The kind of tooth eariest susceptible to caries was the mandibular first molar (about 70% suffered from caries 2 years post-eruptively), followed by the maxillary first molar (about 50% suffered from caries 2 years post-eruptively). The second molar showed a similar caries inclination as the first molar.
2) The kind of tooth least susceptible to caries was the mandibular cuspid tooth, followed by the maxillary cuspid tooth and the mandibular incisors.
3) By groups according to time of birth, the group involving later birth showed lower caries-suffering inclination, and this was noted for the first molar, maxillary incisors and bicuspid teeth and especially to a remarkable extent for first molar from three years after eruption on.
4) The results of evaruation by Cariostat at the start of eruption of the permanent teeth and the DMF ratio following eruption of permanent teeth showed a positive correlation concerning the kinds and groups of teeth having a high tendency to suffer from caries and to an especial extent for the mandibular and maxillary first molars. On the other hand, no such correlation was noted concerning the kinds and groups of teeth having a low tendency to suffer from caries. The group of maxillary incisors showed such positive correlation in conncidence with the time-course of caries-suffering condition.
5) The relationship between the results of evaruation by Cariostat at the start of eruption of permanent teeth and D ratio, F ratio following eruption of the permanent teeth showed different aspects according to the kinds and groups 788of teeth, indicating a positive correlation almost in coincidence with the cariestreating condition.
6) Mandibular bicuspid teeth showed an age rerayed tendency to suffering from caries and correlations with DMF ratio, D ratio and F ratio were poor.
7) The above results suggested Cariostat at the start of eruption of permanent teeth to be an effective index of prediction of the aged carious condition of permanent teeth according to the kinds and groups of teeth.
