Clinical and microbiological caries-risk parameters at different stages of dental development.

Caries incidence and activity in general are not linear functions, but show several intensity peaks at different stages of life. The purpose of this study was to evaluate, whether the transition from the primary to the permanent dentition is accompanied by any significant changes in several clinical and microbiological parameters commonly used as predictors of caries activity. Sixty children and adolescents, aged 3 to 16, participated in the study and according to age were assigned to 4 different dentition groups (primary, early mixed, late mixed, permanent). The results indicate, that there is a significant decrease in salivary Streptococcus mutans and Lactobacillus spp. counts in the late mixed dentition group compared to the primary and the early mixed dentition group. Furthermore, in the permanent dentition group the stimulated salivary flow rate was significantly higher than in all other groups. Differences regarding plaque score and salivary buffering capacity were not significant for all groups examined. It is concluded, that the transition from the primary to the permanent dentition in general is accompanied by significant, yet temporary decline in the numbers of caries-associated microorganisms, reflecting marked differences in caries incidence and activity, previously reported by other authors.