SALIVARY LACTOBACILLI EXPLAIN DENTAL-CARIES BETTER THAN SALIVARY MUTANS STREPTOCOCCI IN 4-5-YEAR-OLD CHILDREN

The present comparative study was undertaken to determine which of the bacteria, lactobacilli (lbc) and mutans streptococci (ms), in saliva better explains the variation of caries in 2728 South African 4-5-yr-o ld children. Caries was diagnosed according to WHO criteria. For Ibc, the Dentocult system was used. The number of ms in stimulated saliva w as counted on MSB agar plates. For correction of confounding factors, data on the frequency of intake of sweets were derived from extensive interviews. Oral hygiene was determined according to the simplified de bris index of GREENE & VERMILLION. Simple correlation analyses between dmfs and bacterial counts were done for the total material and for th ree caries intervals by calculating Spearman's and Pearson's coefficie nts of correlation. Multivariate regression analyses were done on all intervals to correct for the confounding effects of regular intake of sweets, presence of salivary ms or Ibc, and oral hygiene. Of the child ren, 68% had detectable Ibc in the saliva, and 74% had ms. Except for children with more than 6 dmfs, the explanatory values, i.e., percenta ge of variation in dmfs explained, were higher for lbc than for ms. Be fore correction, the values for the total material were 15 vs 6%; for children with caries, 7 vs 5%; for those with 1-6 dmfs, 5 vs 0.4%; and for those with more than 6 dmfs, 0.3 vs 2%. All r-values were reduced after correction, indicating that the confounders explain some of the correlation between dmfs and bacterial count. As was the case before correction, the percentage of variation in dmfs explained by lbc after correction was higher than that for ms, except for children with more than 6 dmfs. The results suggest that lbc explain the variation in ca ries among preschool children better than ms, but the question of whet her lbc is a better predictor remains.