Objective:Compare the stress of abutment and its surface supporting tissues with forging clasp or with casting clasp or with elastic clasp retained both extention removable partial dentures(RPD).

• 目的 :比较在局部可摘义齿修复中锻造卡环、铸造卡环和隐形义齿对基牙牙周组织表面应力的差异。