Abstract
The prevalence of dental caries in first permanent molars was measured in 220 children who have been under regular dental care at the Pediatric Dental Clinic, Tohoku University School of Dentistry. While the caries prevalence rate of first permanent molars reached approx.50 % five years after the eruption, the number of filled surfaces per restored tooth was less than 2.0. The caries prevalence of the permanent mandibular first molars was significantly higher than the caries prevalence of the permanent maxillary first molars. However, the occlusal surface showed no significant differences between the maxillary and mandibular molars. While comparing the female to male group, the caries prevalence rate was significantly higher and the peak of caries occurrence on every surface was earlier in the females. Pit and fissure sealants were applied to approx.75 % of first permanent molars and the occlusal caries were reduced as a result of sealing. When sealants were applied to the teeth diagnosed as C1,50 % were restored due to development of caries. This was a significantly higher rate than that applied to sound teeth. Our study indicates that most of the occlusal caries occured in the earlier stage of 1-2 years after the eruption, before sealants were applied. The buccal fissure of the lower molars and the occlusal fissures both showed high caries prevalence. It was suggested that prevention of fissure caries immediately following eruption until the sealant is applied is an important issue in our present dental care system.
