Investigation of wear in manual toothbrushes from different price categories.

This clinical study examined differences in wear in manual toothbrushes from different price categories. 140 volunteers (14 groups of 10) brushed twice daily for 2-3 minutes over a period of three or six months using the modified Bass technique and seven different toothbrushes (TB) from three price categories. A: 2 TB for under 1 Euro; B: 2 TB priced between 1 and 2 Euro; C: 3 TB priced at over 2 Euro. After a period of three or six months the increase in the bristle surface field was determined and the brush heads were rated macroscopically, by light microscopy and scanning electron microscopy (SEM) (grades 1-4: new, small, clear or very clear signs of use). The statistical analysis was performed with the Mann-Whitney U-test and Error Rates method (p < or = 0.05). All bristle fields showed an increase in surface area over the period of use. When examined macroscopically and under light microscopy, very little difference was found between three and six months of use, or between brushes from the same price category. The clearest distinction was found between categories B and C, whereby C was rated worse. In SEM it was difficult to separate the findings according to price categories. Here, the scores most often awarded were 3 and 4. The results of the three test methods differed markedly from one another. Thus no conclusions on the state of the bristles can be drawn from a marked increase in bristle field surface area. The category B TB tended to perform best.