Neurotoxic effects of root canal sealers with different compounds on rat sciatic nerves

The aim of this study was to determine the neurotoxic effects of root canal sealers with different compounds on rat sciatic nerves. A total of 40 male Sprague-Dawley rats were randomly divided into 5 groups: Control, AH Plus, Smartpastebio, Sealapex, and Guttaflow. Sciatic nerves of the rats were exposed and the compound action potentials were recorded for initial, 5, 30 and 120 minutes (early period) and 2 weeks (late period) by using an electrophysiologic data acquisition system for all groups and nerve conduction velocities were calculated. All the rats were sacrificed for histopathological evaluation following late period calculations and sciatic nerves were removed including the non-paste-contaminated area. Statistical evaluation of the data was performed by using Kruskall-Wallis and Mann-Whitney U tests for intergroup variables and Friedman and Wilcoxon test for intragroup variables with correcting p values. It was detected that reduction was observed in nerve conduction velocity in all study groups however this reduction was only statistically significant in AH Plus paste in intragroup evaluations when initial values were compared with 120th minute values (p<0.0125). It was observed that AH Plus and GuttaFlow pastes reached almost near initial nerve conduction velocity values in the late period. Only the difference in AH Plus paste was statistically significant when changes in nerve conduction velocity in initial and late period were compared (p<0.05). When intergroup comparisons were performed, it was observed that statistically significant difference occurred in 30th minute in Sealapex group and 120th minute in AH Plus group compared with the Control group (p<0.0125). It was found that Sealapex paste demonstrated more degenerative effect compared with other pastes in histological evaluation. Though all the pastes used in this study exerted various neurotoxic effects on sciatic nerve, this neurotoxicity was not strong enough to completely block nerve conduction velocity. Key Words: Root canal treatment, Sealer extrusion, Paresthesia, Electrophysiological Processes, Histopathological evaluation