[Elasticity and deviation angle of toothbrush in Korean adults].

The purpose of this experiment was to establish a simple and general recommendation criteria to evaluate the toothbrush whether it was usable or not. We gave 94 adults the same toothbrushes and required them to use only those toothbrushes and recollected them after 4 weeks' use. Then, we determined elasticity loss, deformation degree and deviation angle of the used toothbrushes. From the above data, we compared and analyzed the correlation between loss of elasticity loss and deviation angle. The obtained results were as follows: 1. In Korean adults, there was no statistical difference between elasticity loss and deviation angle according to both age and sex group (p greater than 0.05). 2. There was no statistical correlationship between elasticity loss and deviation angle (r = 0.15, p greater than 0.05). 3. It was regarded that the determination of deviation angle was more simple method than that of elasticity loss for the evaluation of useful period of toothbrush. 4. In Korean adults, the average usable period of toothbrush was estimated about 1 month.