Effects of toothbrushing prior and/or subsequent to dietary acid application on smear layer formation and the patency of dentinal tubules: an SEM study.

Dentine sensitivity is a quite common condition, associated with open dentinal tubules patent all the way to the pulp. The purpose of this in vitro study was to assess the effects of toothbrushing preceded and/or followed by dietary acid application on the patency of dentinal tubules. Dentine sections were prepared from recently extracted human molars and, after removal of the smear layer, were treated as follows: 1) toothbrushing alone; 2) toothbrushing followed by exposure to orange juice; and 3) toothbrushing subsequent to orange juice exposure. All specimens were observed in the scanning electron microscope (SEM) at a standard magnification and the patency of the dentinal tubules estimated. Results showed that toothbrushing alone was the most effective in occluding the tubules, followed by toothbrushing subsequent to dietary acid application, and then by toothbrushing prior to dietary acid application. From the results of this study it may be that in cases of dentine sensitivity toothbrushing should not precede or follow dietary acid application but be separate from mealtimes. Clinical research is required to confirm the findings of this in vitro study.