材料和方法一、病例选择:通过临床和X线片检查诊断为慢性根尖周炎者,凡经常规根管治疗三次以上,根管内有渗出物,或根尖周有疼痛(叩痛)者,为本治疗的适应证。共治疗60例,男32例,女28例,年龄24～60岁,平均42岁,上、下前牙40颗,上双尖 Materials and methods First, the choice of case: through clinical and X-ray examination diagnosed as chronic apical periodontitis who often three times more than root canal treatment, exudate in the root canal or periapical pain (percussion pain ) Who, based on the indications for treatment. A total of 60 cases of treatment, 32 males and 28 females, aged 24 to 60 years old, with an average of 42 years old, upper and lower anterior 40,