LAUSR

AIM To compare the weight of apically extruded debris produced during the removal of root canal filling material using various files in extracted teeth with simulated apical root resorption. METHODOLOGY The root canals of one hundred and twenty extracted mandibular premolar teeth were prepared with Revo-S files and filled using a cold lateral compaction technique with gutta-percha and a resin-based sealer (AdSeal; Meta-Biomed, Cheongwon, Korea). Sixty teeth were randomly assigned to 4 control groups (hand file, ProTaper Universal retreatment file, D-RaCe retreatment file, and Reciproc file) for the removal of root canal filling material. The apical portion of the remaining 60 teeth was modified to simulate apical root resoption and the teeth were then randomly divided into 4 experimental groups (same techniques as in control groups) for the removal of root canal filling material. Apically extruded debris was collected into pre-weighed Eppendorf tubes and then dried. The mean weight of the apically extruded debris was assessed with an analytical balance to an accuracy of 10-4 g. Data were analyzed by using two-way analysis of variance and a Tukey's post hoc test. RESULTS In the simulated apical root resorption groups, the all file systems were associated with significantly more debris extrusion compared to the groups without resorption (P < 0.05). The amount of apically extruded debris was greatest in the hand file groups compared to the other groups (P < 0.05). In the groups with simulated apical root resorption, Reciproc was associated with the least apically extruded debris (P < 0.05). Whereas there was no significant difference between the ProTaper Universal retreatment and D-RaCe files (P > 0.05). In the groups without simulated apical root resorption, there was no significant difference between Reciproc, ProTaper Universal retreatment and D-RaCe retreatment files (P > 0.05). The time required to remove the root canal filling material was: hand file > ProTaper Universal retreatment=D-RaCe retreatment > Reciproc (P < 0.05). CONCLUSIONS The weight of apically extruded debris was greater in teeth with simulated apical root resorption than in those teeth without simulated apical root resorption. Hand files were associated with more apically extruded debris in all groups during removal of the root canal filling material.