THE FORMATION OF EARLY CARIOUS LESIONS IN DENTAL ENAMEL

PART II

¹ Institute of Dental Research, United Dental Hospital, Sydney, Australia

1. The permeability of enamel subjected to the action of acid buffer solution was noticeably increased. When stained with alizarin red S on the surface, all structures were uniformly involved. At a deeper level, the affected areas were restricted to the margins of the prisms, the prism sheaths, and interprismatic substance, while the deepest penetration was confined to the areas of the prism sheaths.

2. Ninhydrin, Morgan-Elson, and Hotchkiss tests were made on enamel under various conditions. These revealed that (a) the protein structure of enamel is not broken down by acid decalcification; it can be broken down by boiling in strong acid; and (b) the protein of enamel contains a hexosamine indicating the existence of a mucopolysaccharide.

3. Enamel is permeable to solutions of silver nitrate. The route by which such solutions penetrate is identical with that taken by the solutions of lactic acid.