|Budget Amount *help
¥6,900,000 (Direct Cost : ¥6,900,000)
Fiscal Year 1995 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1994 : ¥6,100,000 (Direct Cost : ¥6,100,000)
The purpose of the present study was to inveatigate the effects of some factors on cleaning by toothbrushing, and determine optimum conditions to sufficiently clean tooth surfaces. Using a special brushing machine, the effects of the surface configuration, the toughness of brush bristles, and the stroke, angle and force of brushing on the cleaning were investigated based on the principles of friction work. In relation to these results, the elastic properties of the bristles were measured. A clinical study and the machine testing were carried out to determine the optimal conditions of toothbrushing. From the results of these studies, the following conclusions are drawn.
1. The cleaning effect of toothbrushing is affected by the configuration of a tooth surface, the toughness of bristles, and the stroke, angle, force, speed and frequency of brushing. Ingeneral, the surface configuration, the brushing stroke, angle, and force have interactions each other, and thus the effects of these factors vary with the change of the other factors. 2. The bristles hardly contact the concave surfaces under some specific conditions (i. e. brushing angle : 90ﾟ, force : 200gf). On the convex surfaces of a premolar and a molar, the contact and the frictional movement of the bristles are very little under some specific conditions (i. e. brushing angle : 90ﾟ, stroke : 10mm, force : 400gf). These may be the main reasons for remaining plaque after brushing.
3. The following conditions are recommended to obtain high cleaning effect both on convex and concave surfaces. 1) brushing angle : 90ﾟ, bristles : high stiffness, brushing force : 300-400gf, brushing stroke : use both 10mm and 20mm, 2) brushing angle : 90ﾟ, bristles : high stiffness, brushing stroke : 10mm, brushing force : use both 200gf and 400gf, 3) brushing angle : 45ﾟ, bristles : high stiffness, brushing force : 300-400gf (In this case, longer brushing time may by required.)