the Youth Development Project of Army Military Medical University,No.2018XQN014;the Clinical Innovation Project of Army Military Medical University,No.2019XLC2014;the Science and Technology Foundation of Chongqing,China,No.cstc2014jcyjA10092.
BACKGROUND Root canal retreatment is common after root canal therapy in clinical situations.Especially,completing the retreatment of variant root canals can be challenging.This is particularly true for the molars loca...