Progress toward understanding the contribution of alkali generation in dental biofilms to inhibition of dental caries

Alkali production by oral bacteria is believed to have a major impact on oral microbial ecology and to be inibitory to the initiation and progression of dental caries. A substantial body of evidence is beginning to accumulate that indicates the modulation of the alkalinogenic potential of dental biofilms may be a promising strategy for caries control. This brief review highlights recent progress toward understanding molecular genetic and physiologic aspects of important alkali-generating pathways in oral bacteria, and the role of alkali production in the ecology of dental biofilms in health and disease. Oral bacteria that decrease mouth acidity by producing alkali are key players in preventing cavities, according to a review by Robert A Burne of the University of Florida and his colleagues. Mouths are colonized by hundreds of types of bacteria that form biofilms on teeth and contribute to either oral health or disease. Some of these bacteria decrease mouth acidity by metabolizing substances — urea and arginine — that are naturally present in saliva. Burne and colleagues reviewed evidence that these bacteria thereby encourage growth of cavity-preventing bacteria and help to remineralize teeth. They note that more research is needed to clarify whether cavity-free patients have different bacterial communities, or simply different mouth environments. Further studies could also determine whether oral health can be improved by supplementation with arginine or probiotics containing the helpful bacteria.