Alkali production by oral bacteria and protection against dental caries

pH is a key environmental factor affecting the physiology, ecology and path ogenicity of the oral biofilms colonizing the hard tissues of the human mou th. Much attention has been focused on the production of organic acids thro ugh the metabolism of carbohydrates by pathogenic oral bacteria. Now, evide nce is emerging that alkali generation, particularly through ammonia produc tion from arginine and urea, plays major roles in pH homeostasis in oral bi ofilms and may moderate initiation and progression of dental caries. This s hort review highlights recent progress on understanding molecular genetic a nd physiologic aspects of ammonia generation by prominent oral bacteria. (C ) 2000 Federation of European Microbiological Societies. Published by Elsev ier Science B.V. All rights reserved.