Scanning laser microscopic surface profiles of human enamel and dentin after brushing with abrasive dentifrice in vitro.

Automatic brushing with and without commercial dentifrice containing calcium hydrogen phosphate as an abrasive, commonly available in Japan, was performed on the tangential ground surfaces of sound enamel and dentin in human young premolar teeth with loading of about 120 g for 10 minutes in vitro. Their brushed surfaces were observed with a scanning electron and a scanning laser microscope. Brushing with abrasive dentifrice caused rough surfaces to appear and the abrasion of the enamel and the dentin was measured to be about 0.1 and 1.5 microns/min in mean depth, respectively. Under brushing with only distilled water, however, the enamel surfaces remained intact while the dentin surfaces became smoother.