う蝕
Teeth are bathed in saliva and have a coating of bacteria on them (biofilm) that continually forms. The development of biofilm begins with pellicle formation. Pellicle is an acellular proteinaceous film which covers the teeth. Bacteria colonize on the teeth by adhering to the pellicle-coated surface. Over time, a mature biofilm is formed and this create a cariogenic environment on the tooth surface. The minerals in the hard tissues of the teeth (enamel, dentin and cementum) are constantly undergoing processes of demineralization and remineralization. Dental caries results when the demineralization rate is faster than the remineralization and there is net mineral loss. This happens when there is an ecologic shift within the dental biofilm, from a balanced population of micro-organisms to a population that produce acids and can survive in an acid environment.