Effect of Probiotics on Dental Caries Risk: A Systematic Review

Objectives: To evaluate the evidence of probiotic effects on dental caries risk and dental caries lesion development.
Methods: A systematic review was done. Randomized Clinical Trials (RCTs) without time or language restrictions were searched (up to May 2015). We searched in the following electronic databases: Pubmed, Web of Knowledge, Scopus and Embase; a hand searching based on the included papers was also conducted. “Probiotics” AND “Dental caries” AND “Clinical trial” were the MeSH terms used and only RCTs where dental caries was the primary outcome were considered. Two reviewers carried out study selection independently with disagreements being resolved by discussion. Relevant information was recorded in worksheets and scoring against CONSORT 2010 checklist assessed the trials quality report, papers were deemed as excellent (≥20 items), good (19-13 items) and poor (≤12 items).
Results: The search strategy identified 232 citations, 61 RCTs were found and 6 met the inclusion criteria. According to the CONSORT guidelines, one trial was rated as excellent and five as good. These papers had a parallel double-blind design; the number of participants was higher than 100 including children and adults and the most common probiotics used were L. rhamnosus GG and L. rhamnosus LB21. Three studies used milk-containing probiotic as vehicle; the shortest intervention took seven months and the longest 21. The caries risk reduction was calculated using the dmft/DMFTs index and stimulated whole saliva and/or plaque samples were taken for the microbial analysis. Half of RCTs found a statistically significant caries reduction and the others showed an apparent caries risk reduction but not statistically significant.
Conclusions: The evidence is not conclusive. However, the use of probiotics may be promising if we have in mind that a reduction of mutans streptococci and lactobacilli counts have been demonstrated and that could be used as surrogate outcome for dental caries.