牙体严重缺损,常用嵌体或人造冠来修复。1958年Markleg首用金属丝支架作固位钉以加强银汞合金的固位作用和抗压作用,Enoch曾安置4～8个固位钉在无外侧壁的牙洞用银汞合金充填,也能增加对移位的抗力,并用于修 Serious tooth defects, commonly used inlays or artificial crown to repair. In 1958, Markleg first used wire braces as retention pins to reinforce amalgam retention and compressive forces. Enoch placed 4 to 8 retention pins in silver-free amalgam-free dental cavities. Can increase the resistance to displacement, and used to repair