The Formation of Early Carious Lesions in Dental Enamel

Abstract

The permeability of the enamel, after being subjected to acid, increases noticeably. Such affected areas stain a bright red with aqueous solns. of alizarin red S, the first substance to be affected being the prism sheath, followed by the interprism substance and, finally, the body of the prism. Ninhydrin, Morgan-Elson and Hotchkiss reactions indicated that the protein structure of enamel is not broken down by decalcification by acid but it could be destroyed by boiling in strong acid. A mucopolysaccharide was demonstrated in the normal enamel. Normal enamel was also shown to be permeable to solns. of silver nitrate which penetrated along paths similar to those followed by the penetration of acids. These investigations offer some indication as to the method of formation of a carious lesion.