Nitrogen in human dental enamel.

Dental enamel is the structure which is first exposed to the attack of dental caries, and the success or failure of this attack depends on many factors, among them the chemical nature and structure of the enamel. Some authors (Pincus, 1939; Gottlieb, 1947) go so far as to postulate that the caries process is initially a proteolytic one. In this connexion the nitrogenous material of enamel is of interest. The object of the present experiments was to estimate the nitrogen content of enamel on samples of material which were representative of the main enamel mass and uncontaminated by dentine. Enamel is firmly attached to the underlying dentine which contains about 3-5% nitrogen compared with about 0-15% in enamel. On these figures, even a 2% dentine impurity would increase the enamel nitrogen by about 60 %.