A systematic study of the plaque removal efficiency of worn toothbrushes.

This study described a new in vivo methodology for measuring and comparing plaque removal efficiencies of different toothbrush designs and used it to quantify the loss of plaque removal efficiency of worn toothbrushes, as well as to elucidate the causes. Worn toothbrushes produce statistically significant and large decreases in plaque removal ability depending upon their state of wear. While both bristle matting and bristle tapering contribute to this loss, the former appears to be the more potent. Thus brush designs that are resistant to bristle matting should show markedly superior durability. An indirect conclusion from the bristle tapering results is that the softer a brush, the less plaque it will remove. As a practical conclusion, it is recommended that a standard toothbrush be discarded when it shows signs of matting, regardless of age.