Can acids produced from probiotics demineralize the tooth and cause progression of caries: a critical review

Background: Probiotics are live microorganisms which that provide various health benefits to the host upon administration in adequate amounts. Lactobacilli, Propionibacterium, and Bifidobacterium are common “Lactic Acid-producing bacteria (LAB)” present in various probiotic formulations. These probiotic bacteria release many organic acids, mainly lactic acid, acetic acid, and propionic acid into their surrounding environment. Increased concentration of these inorganic and organic acids reduces the saliva’s critical pH to below 5.5, and initiates demineralization. Thus, the present review aims to critically appraise the existing evidence on this emerging clinical perspective and double edged nature of the probiotic bacteria, and explain as to how probiotic supplements increase the risk of tooth decay. Results: Lactobacilli and Bifidobacterium were associated with rampant caries in preschool children and progression of caries. All probiotics were acidogenic as they decreased the pH of the saliva, demineralized and eroded the enamel. Probiotics also release extracellular polysaccharides that help to release essential elements like calcium and phosphorous from the enamel surface. The lactic acid-producing efficiency of probiotics is increased when combined with supragingival plaque. Low pH was attributed to the interaction of Lactobacilli with other microorganisms. Conclusion: Acids release from probiotics bacteria can lower the critical pH of the oral cavity to below five, and play a role in demineralization of the tooth and progression of caries.