Effect of toothbrush wear on plaque control.

The purpose of this study was to investigate the effect of progressive toothbrush wear on plaque control. At baseline (week 0), each of 20 subjects was given a new toothbrush which they used for the 9-week period of the study. At weeks 0, 3 and 6, all plaque was professionally removed. The amount of plaque which accumulated in each of the 3 successive 3-week experimental periods was assessed at weeks 3, 6 and 9. Toothbrush wear was evaluated by measuring the increase in the brushing surface area of toothbrushes at weeks 3, 6 and 9 as compared with week 0. The brushing surface area was measured by computer analysis of tracings of the brushing surface outlines obtained from standardized photographs. Despite progressive toothbrush wear, the amount of plaque which accumulated in each successive 3-week period decreased. The decrease in plaque scores between weeks 3 and 6 and between weeks 3 and 9 were found to be highly significant (p < 0.001). Toothbrush wear varied widely amongst the subjects. When plaque scores were evaluated for the 10 subjects with highest toothbrush wear, and the 10 with lowest wear, no significant differences were found between the 2 subgroups. Under the experimental conditions of this study, progressive toothbrush wear did not lead to a decrease in plaque control. The improvement in plaque scores may have been due to motivational effects resulting from study participation and anticipation of oral examinations. It was concluded that the wear status of a toothbrush may not be critical in ensuring optimal plaque control.