dove-tail groove

The dovetail of occlusion were prepared in the one group,the two retention grooves were prepared in the buccal or lingual axial angle in the other group.

方法　后牙邻面龋和邻面龋 (面损坏不超过 1/ 3)患牙2 76颗 ,常规制备邻面洞后 ,随机分为 2组 ,一组在面按常规备制成鸠尾 ,另一组仅在颊轴角及舌轴角处作 2条固位沟 ,两组均用银汞合金充填 ,随访 3年。