Methods Calcium hydroxide water-soluable paste was sealed into 50 root canals seperated as a observation group while formo-cresol was applied to another 50 root canals as a control group.

• 方法观察组50个根管用氢氧化钙水溶性糊剂封入根管内消毒;对照组50个根管封入甲醛甲酚。