Effect of apically separated rotary instruments on bacterial leakage of obturated root canals using resilon.

: The purpose of this study was to determine the effect of a separated rotary instrument on the time required for bacterial penetration of obturated root canals using Resilon. Eighty-four extracted human maxillary premolars with single canals were used in this study. Group 1 consisted of teeth obturated with gutta-percha and AH-26 sealer (n=15); Group 2 consisted of teeth obturated similarly to Group 1 but without a separated file; Group 3 consisted of teeth obturated with Resilon and Epiphany sealer (n=15); and Group 4 consisted of teeth obturated similarly to Group 3 but without a separated file. Six teeth were used as positive controls, and six teeth were used as negative controls for each experimental group. Negative controls were obturated similarly to experimental teeth. On the other hand, positive controls were obturated with gutta-percha or Resilon without sealer. A suspension of Enterococcus faecalis was placed in the access chamber daily, and penetration was determined when turbidity was noted in the culture broth during a three-month period. No significant difference between experimental groups was observed. However, differences between experimental groups and control groups were statistically significant.