CARIES INCIDENCE IN RELATION TO SALIVARY MUTANS STREPTOCOCCI AND FLUORIDE VARNISH APPLICATIONS IN PRESCHOOL-CHILDREN FROM LOW-FLUORIDE AND OPTIMAL-FLUORIDE AREAS

Caries incidence during a 2-year period was studied in 4- to 5-year-ol d children from three areas with contrasting levels of natural fluorid e (F) in the drinking water and different regimens of topical fluoride varnish applications; group A (n = 448) was from an area with a low l evel off (0.1 ppm) and semi-annual applications of fluoride varnish; g roup B (n = 374) was from a low F area (0.1 ppm) and no fluoride varni sh treatments; group C (n = 206) was from an area with optimal F (1.2 ppm) and fluoride varnish treatments. All children were clinically ass essed at baseline and after 2 years according to WHO criteria. The num ber of salivary mutans streptococci was estimated and scored at baseli ne and after 2 years with the Strip mutans method. The varnish contain ing 0.1% F was applied every 6 months on all accessible tooth surfaces after cleaning with a pumice paste. Basic preventive care was given t o all children and restorative treatment on individual indications. Hi gher levels (p<0.05) of salivary mutans streptococci were found in the low-fluoride areas compared to the optimal fluoride area at baseline and after 2 years. The caries incidence (mean dft +/- SD) in the diffe rent groups was A: 0.65+/-1.40; B: 1.09+/-1.85; C: 0.53+/-1.09. The di fference between group B and groups A and C was statistically signific ant (p<0.05). A positive relationship (p<0.05-0.001) between salivary mutans streptococci scores at baseline and caries incidence was found in all three groups. This study confirms the close association between salivary mutans streptococci and caries incidence in preschool childr en and suggests a caries-reducing effect of topical applications of th e fluoride silane varnish.