The performance of ProTaper system during the endodontic retreatment

Resumo

The development of new rotary instruments for endodontic treatment
demands new studies to evaluate their efficacy on the retreatment of
root canals. The scope of this study was to analyze the partial or total
removal of the filling material by the ProTaper system in the retreatment
of gutta-percha-filled root canals, as well as the time required to reach
the previous working length. Thirty-six human canines were equally
divided in three groups (n=12) and had their root canals prepared by
the following methods: GI=Thermafill system; GII=McSpadden; GIIIlateral condensation. After that, all specimens were retreated without
solvent and using the ProTaper system. The time necessary to remove
the filling material was registered. After the removal of the filling material,
the specimens were sectioned longitudinally and magnified images of
the sections were recorded and printed. The presence or absence of
remaining filling material was registered. The results showed a significant
statistical difference between the McSpadden group and the others with
relation to the time required for filling removal. All groups exhibited an incomplete removal of the filling material. It can be concluded that
although the rapidity that the ProTaper instruments reached the working
length, the system has to be associated to another retreatment.