Human tooth development the cells of the IEE secrete an organic matrix against the dentin. This matrix immediately mineralizes and becomes the initial layer of the tooth's enamel. Outside the dentin are the newly formed ameloblasts in response to the formation of dentin, which are cells that continue the process of enamel formation; therefore, enamel formation moves outwards, adding new material to the outer surface of the developing tooth. Enamel formation is called amelogenesis and occurs in the crown stage (advanced bell stage) of tooth development. "Reciprocal induction" governs the relationship between the formation of dentin and enamel; dentin formation must always occur
Tooth decay rarely does caries affect the cementum alone. Roots have a very thin layer of cementum over a large layer of dentin, and thus most caries affecting cementum also affects dentin. In the Western world, the primary approach to dental hygiene care consists of tooth-brushing and flossing. The purpose of oral hygiene is to remove and prevent the formation of plaque or dental biofilm. While evidence that flossing prevents tooth decay is limited, the practice is still generally recommended. As the amount of bacterial plaque increases, the tooth is more vulnerable to dental caries when carbohydrates in the food are left