Surface roughening of human enamel after toothbrushing.

Grooves and scratches on the enamel surface are potential and preferential sites for bacterial adhesion. During toothbrushing groove formation is a potential risk especially in dentin. To obtain information on groove formation in enamel a profilometric experiment has been carried out on polished human enamel. The main result is that no groove formation with a depth more than a few tenths of a micrometer is observable even after 50.000 toothbrush strokes. The fact that material is removed by toothbrushing is indirect proof that enamel is removed by continuous brushing in layers more or less parallel to the original surface.