Comparison of the extruded apical debris rate following rotary and hand instrumentation techniques during endodontic retreatment

ABSTRACT

Non-surgical retreatment is a way to correct the factors responsible for the failure of previous endodontic treatment. In recent years, rotary instrumentation systems have created a new option for both clinicians and patients. The aim of the present study was to quantify and compare the amount of debris extruded from apical foramen during endodontic retreatment using rotary and hand instrumentation techniques with and without use of chloroform. In this invitro experimental study, root canals of 96 extracted single-root human teeth were instrumented by passive step back technique in three different working lengths optimum, over and under [three subgroups a, b, c]. they were then obturated by a combination of cold lateral and warm vertical compaction methods. After removal of gutta-percha, re-instrumentation was performed in three groups as follows group A; stainless sled K-type hand files plus chloroform, group B; rotary Ni-Ti files plus chloroform and group C; rotary Ni-Ti files without chloroform. Finally, the weight of extruded debris was blindly determined. The results were analyzed by Univariate ANOVA. In all groups, the mean weight for extruded debris was not more than 0.37 gr. The weight of extruded debris was ranked as Group B>Group C>Group A. The differences between three groups and subgroups were statistically significant [P<0.001]. The results of this study showed that the largest amount of extruded debris during retreatment was found after using rotary files with solvent and in canals with overfilled obturation