After the toothbrush is used, there are water and small invisible food residues hidden between the thick bristles. In this humid environment, bacteria just use it as a breeding ground for breeding. The correct maintenance method is for children. After passing the toothbrush, rinse immediately, spin dry, and put the bristles up in a ventilated and dry place. Even if this can be done, the bacteria growing in the bristles exceeds the allowable level in about 3 to 5 months. Therefore, in addition to the correct maintenance of the toothbrush, a new toothbrush should be replaced for the child within 3 to 5 months. This cost is worth the child's dental care.
https://www.samemater.com/toothbrush/child-toothbrush/environmentally-friendly-cartoon-children-s.html