| 摘要 |
The present invention provides a toothbrush comprising, in a bristle implanting surface, a central bristle bundle group formed from two or more central bristle bundles positioned substantially centrally on the bristle implanting surface, a first outside bristle bundle group formed from two or more outside bristle bundles with the central bristle bundle group interposed therebetween, and a second outside bristle bundle group. A region encircled by an annular line that joins the outer edge of implanted bristle holes positioned on the outermost periphery of the central bristle bundle group and wherein the central bristle bundles are implanted shall be a central implanted bristle region, the value obtained by dividing the total number of bristles in the central bristle bundle group by the area of the central implanted bristle region shall be the central implanted bristle density, the region for the first outside bristle bundle group shall be the first outside implanted bristle region, the region for the second outside bristle bundle group shall be the second outside implanted bristle region, the value obtained by dividing the total number of bristles in the first and second outside bristle bundle groups by the sum of the area of the first outside implanted bristle region and the area of the second outside implanted bristle region shall be the outside implanted bristle density, and the implanted bristle density ratio indicated by the outside implanted bristle density/the central implanted bristle density shall be 1.6-6.0. The present invention provides a toothbrush that can provide both a gentle sensation on the gums and highly effective cleaning of the tooth cervix. |
