Toothbrush resistance and fluoride retention of sound, etched, fluoridated, and remineralized bovine enamel.

The wear resistance of tooth enamel that had undergone eight different treatments regarding the bonding procedure has been investigated. In comparison to sound enamel, the outer 3 microns of the etched-surface enamel show a decreased wear resistance against toothbrushing in vitro. Remineralization, either direct or preceded by acidified phosphated fluoride (APF) application, did not improve the wear resistance. The prophylactic effect of the APF treatment of etched enamel is considerable and is not lost after the soft, outer surface layer has worn off.