Applicability of acid-etching techniques for fluoride determination on enamel after topical fluoride treatment

Abstract

A common technique for fluoride gradient determination of enamel is based on acid-etching of thin enamel layers. The dissolution of CaF₂-like material in two different acid-etching solutions was compared with the dissolution of pure CaF₂. The results showed that the CaF₂-like material deposited on enamel after a topical treatment with 2% NaF dissolved almost completely in the 1 M HClO₄ and 1.6 N HCI/70% glycerol solutions. The dissolution of pure CaF₂ in the same solutions was low. Even after 30 min, less than 9% of the CaF₂ had dissolved. It was concluded that acid-etching techniques for fluoride determination could be used on enamel treated topically with fluoride. The study also indicated that CaF₂-like material may have chemical properties different from pure CaF₂.