以往残根（冠）多采用简易成品桩或铸造桩予以保留和修复［１］。上部塑料修复体易老化，不耐磨，塑料或复合树脂与成品桩的结合强度有限，修复后会出现塑料变色及磨损，甚至脱落［２］。铸造桩核避免了简易树脂桩冠的缺点，其精密度高，在异位牙改向或作桥基牙固位体时易... In the past residual roots (crown) more simple finished pile or casting pile to be retained and repaired [1]. The upper plastic prosthesis is easy to aging and not wear-resistant. The combination strength of plastic or composite resin and finished product pile is limited, plastic discoloration, wear and even plastic shedding will occur after the repair [2]. Casting stubs to avoid the shortcomings of simple resin crown, the high precision, in the direction of the alien tooth to change or as a bridge abutment bit holder easy ...