Caries in the primary teeth and salivary Streptococcus mutans and lactobacillus levels as indicators of caries in permanent teeth.

The relation between dental caries in the primary and permanent dentitions of the same individuals was studied during the period of general decline of caries in the child population. The caries activity of the study group in their teens, measured by cariesrelated microbial tests and clinical parameters, was low. However, the results suggest hat caries experience of the primary dentition was associated with caries experience of the subsequent permanent dentition. The association was strong in persons who were cariesinactive and weaker in those who were caries-active in the primary dentition. Numerous previous studies have shown a significant correlation between caries experience in the primary and permanent dentitions. 1 However, there has been a strong decline in the caries prevalence during the last 10 to 15 years in many countries, including Finland. While 10 years ago only 10-20% of the 5-year-old children living in Helsinki were caries free, 60% of 5-year-old children are currently caries free. As an example of caries prevalence in the permanent dentition, the corresponding DMFT for 15year-old children in 1975 and 1985 were 12.4 and 5.6. It has been shown that the decline in caries also is reflected in the levels of salivary Streptococcus mutans and lactobacilli (Klock and Krasse 1985), which measures have been used to indicate caries activity in a child population. 2 In this longitudinal study the object was to determine whether this decline in caries has affected the association between caries in the primary and permanent dentitions. The authors also wanted to evaluate the levels of S. mutans and lactobacilli in saliva of the child group and determine Adler 1968; Hill et al. 1967; Klein et al. 1981; Parfitt and Parfitt 1954; Poulsen and Holm 1980. Klock and Krasse 1979; Zickert et al. 1982; Zickert et al. 1983. whether their present caries activity can be confirmed using bacteriologic tests. Methods and Materials The study group consisted of 129 Finnish children living in Helsinki, part of a larger follow-up study on oral health and dental development (Nystr/Sm 1982). The children were examined annually from the age of 6 months. Preventive and restorative dental care was provided for all children at public dental care centers. Treatment was provided on a yearly basis and included dietary information, oral hygiene instructions, and topical fluoride treatment. Fluoride mouth rinses were given at school every second week beginning at the age of 7 years. Fluoride tablets were given for about one-third of the children from the age of 6 months to the age of 12 years. From the age of 6 months to the age of 8 years two-thirds of the children were given mineral preparations which consisted of bone meal. During each visit in the present study the children were motivated for caries prevention and, if necessary, sent to have preventive and restorative care. At the final examination, the children were 1217 years old (mean age 15.5). Carious lesions were recorded according to M61let (1966). Radiographic examination has been performed in susceptible cases to aid in clinical diagnosis. The incipient lesions, including visible decalcified spots on the enamel and enamel surface lesions in the radiograph, were not recorded. DMFS, DS, and dmfs indices (decayed, missing, and filled surfaces) were used. In the primary teeth the cumulative dmfs index was calculated by counting all affected surfaces up to the age of 9 years. The level of salivary Streptococcus mutans and lac126 CARIES EXPERIENCE: Alaluusua et al.