EFFECT OF NICKEL-TITANIUM ENGINE-DRIVEN INSTRUMENT ROTATIONAL SPEED ON ROOT-CANAL MORPHOLOGY

Thirty-six mesial canals in 18 extracted human mandibular molars were randomly allocated to three experimental groups. Specimens were prepar ed and evaluated using a modified Bramante technique. Teeth were secti oned at the midroot and apical regions. Canals were prepared with the Lightspeed instruments rotating at 750, 1300, or 2000 rpm. Digitized u ninstrumented and instrumented canal images were compared via subtract ion software. There was no significant difference (p < 0.05) among the three experimental groups in the amount of dentin removed, canal tran sportation, or the ability of the instrument to remain centered in the canal.