Regular teeth cleaning ( brushing ) and nail clipping are also important .

经常的 牙齿清洁（刷牙） 和修剪 指甲也是非常重要的。

Teeth were randomly separated into six groups of 10 each and 2 positive controls . All experimental teeth were covered with three layers of nail varnish to prevent leakage from the root surface leaving the apical 2-3 mm uncovered .

并将其随机分为6组，每组10 颗， 并有2 颗作为阳性对照。