Influência da velocidade do movimento reciprocante na remoção do material obturador em retratamentos de canais radiculares

Abstract

The present study evaluated the influence of the speed of the reciprocating movement in the removal of filling material in retreatment of root canals. Forty anterior mandibular human teeth had their root canals prepared by the crown down technique, being filled by the hybrid Tagger technique. After three months ,the specimens were randomly divided into two retreatment groups according to the speed of the reciproc system R50 instruments, without solvent. In group 1 the instruments were driven at 600 rpm and in group 2 at the speed indicated by the manufacturer, of 300rpm. To evaluate the percentage of residual filling material, the teeth were longitudinally sectioned, and photographed under a dental operating microscope with 8X magnification. Images were transferred to a computer, and residual filling material was quantified using Image Tool software (University of Texas Health Science Center, San Antonio, TX). Results were compared using Mann- Whitney non-parametric test (p < .05). All teeth examined had filling remnants within the canal. No statistically significant difference (p > .05) in residual filling material was observed among the groups, with 5.10% in group1, and 6,1% in group 2. Thus, it is concluded that mechanized instruments with reciprocating kinematics for retreatment of root canals is an efficient operative resource and that the increase of the speed to 600 rpm does not influence the removal of filling material when compared to the speed recommended by the manufacturer.