In addition,45 teeth with chronic apical periodontitis were also divided into two groups,one was treated with CRD(25 teeth), the other was continually treatd with usualdrug.

• 另外还分析了45例龋源性慢性根尖周炎，痰管形成，常规封药1.；2次仍有症状，其中25例改用自制CRD材料治疗，20例继续常规治疗作对照。