Residual fluoride concentrations and scanning electron microscopic examination of root surfaces of human teeth after topical application of fluoride in vivo.

Fluoride concentrations in root surfaces of human teeth after a single topical application with a 2% acidulated sodium fluoride solution in vivo were investigated. Increased residual fluoride concentrations in the root surfaces and precipitations on the peritubular dentin, as revealed by SEM micrographs, may be factors in reducing hypersensitivity.