牙刷更換的時機
定期每6~8週更換牙刷，若是從牙刷背面看到刷毛岔開外翻，就表示刷毛很蓬鬆了，必須更換；或是根部累積太多食物殘渣，都要考慮換新牙刷。要隨著孩子的年齡選擇適合尺寸的牙刷，切勿因貪圖方便和大人共用牙刷。

It's recommended to change a toothbrush every 6 to 8 weeks. If you can see the bristles splitting from the back of the toothbrush, it means the bristles are already too worn out and should be replaced. In addition, if the roots of the toothbrush have accumulated too much food debris, you should also consider changing a toothbrush. Make sure to select an age-appropriate toothbrush as children grow up. Parents should not share a toothbrush with children out of convenience.