Acid Production in Dental Plaque After Exposure to Probiotic Bacteria

The increasing interest in probiotic lactobacilli in health maintenance has raised the question of potential risks. One possible side effect could be an increased acidogenicity in dental plaque. The aim of this study was to investigate the effect of probiotic lactobacilli on plaque lactic acid (LA) production in vitro and in vivo.

Methods. subjects (n=18) were given lozenges with probiotic lactobacilli (L. reuteri DSM 17938 and ATCC PTA 5289) or placebo for two weeks in a double-blinded, randomized cross-over trial. The concentration of LA in supragingival plaque samples was determined at baseline and after 2 weeks. Salivary counts of mutans streptococci (MS) and lactobacilli were estimated with chair-side methods.

Inclusion Criteria:

• moderate to high counts of salivary mutans streptococci (>104 CFU) as estimated with the Dentocult SM chair-side test,
• no visible open caries lesions or periodontal disease,

Exclusion Criteria:

• smokers,
• ingestion of probiotic bacteria within the last two months,
• ingestion of antibiotics within the last two months