A comparison was made between the scrub method and the roll method of brushing teeth.
It has been reported that when the roll method of brushing is used, plaque removal, as indicated by the decrease in plaque score, is proportional to the product of the brushing force and the frequency of brushing strokes, and that the largest plaque removal is obtained by brushing with a force of 800g at 30 strokes per twenty seconds. The manual dexterity for manipulating toothbrushes was evaluated by means of a tri-axial strain gauge on the handle of the toothbrush.
In this study of plaque removal using the scrub method, the brushing force was determined by a cathode-ray tube oscilloscope attached to a tri-axial strain gauge on the handle of the toothbrush. The frequency of brushing strokes was determined by synchronization with a metronome. It was concluded that the largest plaque removal was obtained by the scrub method with a force of 400g and 80 strokes per twenty seconds. Plaque removal with the scrub method was proportional to the product of the brushing force (100-400g) and the frequency of brushing strokes (40-80times/20sec).
The better the manual dexterity of handling the toothbrush, the more plaque was removed. The dexterity was evaluated by the direction and magnitude of the strain in the handle and the motions of the brush.
It was found that, for those subjects who showed a 100% decrease in plaque, there was an inverse relationship between brushing force and the frequency of strokes. This was not necessarily the case when the decrease in plaque was less than 100%. This was also a common phenomenon with the roll method.
