对折断于根管内的桩冠固位钉或因治疗、修复需要而必须拆除的桩冠，传统的拆除方法费时，且可造成根管壁侧穿、牙根劈裂、牙周膜损伤等意外。我们采用超声洁治器拆除３６例（４５牙）患者的断桩或完整桩冠，无一产生意外，且保留了完整牙根。现报告如下。临床资料：本组年龄１ The crown removed in the root canal nail or due to treatment, to repair the need to remove the pile crown, the traditional method of demolition time-consuming, and can cause lateral root canal wall piercing, root splitting, periodontal ligament injury and other accidents . We used an ultrasonic scaler to remove 36 cases (45 teeth) in patients with broken stakes or full pile crown, without any accident, and retained the entire root. The report is as follows. Clinical data: the age of this group