Methods In one mouth ,the teeth of one side were as test group ,other side as control group ,the first molar in non-carious pit and fissure of 500 children were sealed.
英
美
- 方法将500例儿童的第一恒磨牙分为两组,一侧第1恒磨牙为一组,对侧同名牙为第2组。