IN VITRO EVALUATION OF THE LIGHTSPEED AND PROFILEROTARY SYSTEMS IN THE PREPARATION OF CURVED ROOT CANALS

Abstract

This in vitro study has been conducted on ninety freshly extracted human mandibular molars having mesial canal angulations ranging between 20 to 40 degrees in order to evaluate the effect of the Profile and the Lightspeed rotary systems on curved root canals together with their recommended .obturation techniques, which are the Thermafil and the Simplifill respectively. This evaluation was conducted in comparison to the standard step-back instrumentation technique using nickel titanium hand K-files and the standard lateral condensation obturation technique. • •.41' This evaluation was conducted on three bases:

1- Canal cleanness: it was evaluated through histologic sectioning of the instrumented canals, for the presence of remaining pulp tissues, predentin, and debris. Statistical analysis of the data showed no significant difference between the Profile, Lightspeed, and Nitiflex files in cleaning curved root canals at #35 apical preparations. 2- Change in canal angulation from both buccal and proximal views: it was assessed by digital radiography analysis of pre and post­ instrumentation radiographs after injection of the tested canals by a radio-opaque material. Statistical analysis of the data showed that the Lightspeed resulted in significantly less change in canal angulation from both buccal and proximal views than did the hand instrumentation technique, and there were no significant difference between any other sub-groups.