| 摘要 |
PROBLEM TO BE SOLVED: To provide a toothbrush using a flat line in brush implantation, which does not cause cracks and whitening in a head part even when a material having low strength is used for the material of the head part.SOLUTION: A flat line 13 has a fragile part 13a. The fragile part 13a is for softening the entire of the flat line 13. When the flat line 13 comes into contact with the interior of an implant hole 12 at the time of implanting a brush B, impact escapes from the fragile part 13a and is absorbed. The fragile part 13a is achieved by a plurality of grooves 13b extending in a direction orthogonal to an implantation direction of the brush B. The plurality of grooves 13b are formed continuously in a direction perpendicular to the implantation direction of the brush B from one end to the other end of the flat line 13 on a surface in contact with the brush B of the flat line 13, and formed in parallel to the implantation direction of the brush B. |
