A polarized light and scanning electron microscopic study of sodium-fluoride treated, acid-etched, caries-like lesions of human enamel.

Precipitation of reaction products into the surface zone and the superficial aspect of the body of the carious lesion occurred after NaF treatment of etched lesions. Surface porosities were noted when NaF treatment was preceded by acid-etching with unbuffered phosphoric acid, which may allow acid-resistant resin bonding to the lesion surface and adjacent sound enamel.