Tooth enamel: current state of the art.

Important progress has been made relative to the growth, structure and function of enamel. Better understanding of the epithelial mesenchymal interactions during odontogenesis has been gained through tissue culture, and the predominant role of the dental papilla has been established. Differences between rodent and human amelogenesis have been demonstrated. With radioautography and cytochemistry, a significant amount of new information has been obtained on the metabolism of the ameloblasts, concerning the synthesis of proteins, glycoproteins and proteoglycans, as well as calcium transport. Numerous biochemical investigations have been devoted to developing and mature enamel matrix. The organic components of human adult enamel are mainly constituted of lipids and proteins, but further investigations are still needed to elucidate their precise nature. The so-called key-hole configuration of adult enamel can be questioned when amelogenesis is considered since the tissue does not develop in a prismatic head-tail fashion. The most important results have probably been obtained in the field of individual enamel apatite crystals shape and ultrastructure as well as in the description of the precise patterns of their carious dissolution which bears great similarities to the dissolution of synthetic apatites in acids.