Method: A double-blind, randomized, placebo-controlled clinical trial was performed, in which 54 7-10 year old children (119 in total) were selected belonging Maipú, Santiago de Chile. The subjects were randomly assigned (STATA 11.2) in two parallel groups: intervention group consumed the probiotic dairy drink containing Lactobacillus johnsonii (10⁷ ufc/ml) and the control group a placebo, during 8 weeks daily. Each participant was examined in three different moments. Salivary streptococci mutans and lactobacilli were enumerated with the test CRT bacteria at an initial moment, at 8 and 4 weeks after consumption ceased. Mann-Whitney test was used to compare the two groups and the Wilcoxon Matched Paired test to compare the distribution of values in between days . The significance level was set at 0.05 for all tests.
Result: A statistically significant reduction (p= 0.006) of salivary streptococci mutans was recorded after the consumption during 8 weeks of dairy drink containing Lactobacillus Johnsonii, effect that is seen 4 weeks after the consumption ceased only in the probiotic group (p=0.0083). The salivary Lactobacilli levels were reduced in both groups, being statistically significant only in placebo group and with non differences when both groups were compared.
Conclusion: Daily consumption of probiotic Lactobacillus Johnsonii dairy drink , may reduce salivary levels of streptococci mutans in children, during the period of consumption and 4 weeks afterwards. Even when the probiotic therapy could become a promising alternative therapy in the conservative management of dental decay, future placebo-controlled clinical trials are needed to evaluate ideal strains with standardized methods and results before any probiotic clinical recommendation in oral health.