Effect of a clamp on toothbrush bristle deterioration

The purpose of this study was to evaluate, in vitro, the effectiveness of a device to prevent toothbrush deterioration. Ten toothbrushes from each of four brands, Oral-B 40, Py-co-pay Softex 12.0 row, Butler #330, and Oral-B 20, were divided into control and experimental groups. Toothbrushes were fixed into a machine that simulated toothbrushing by producing a reciprocating motion 41.5 mm in length at a rate of 380 strokes/min. Bristles slid over a ceramic disc that had a hardness similar to dental enamel. Pressure (450 g) was applied at a right angle to the toothbrush while it moved back and forth in a slurry of toothpaste. The pressure was calibrated with load cells. Toothbrushes were run for 15 minutes followed by a drying cycle for a total of four hours, or approximately equivalent to brushing twice daily for six months. During the drying cycle the bristles of the toothbrushes in the experimental group were compressed 3/4 their length from the brush head with a clamp (Gregory Patent #4884311). Bristle deterioration was evaluated based on Wear Index (WI), a quantitative means of ranking brushes in various stages of deterioration. Data on WI and WR showed that toothbrushes in the experimental group had significantly (< or = 0.005) less deterioration. Improvement in wear resistance was dependent on size and configuration of the bristles. Compressing the bristles between brushings retains the non-matted shape of the bristles and reduces their deterioration.