Résumé
Root canal cleaning is the main purpose of canal instrumentation. Hand instruments leave more debris and smear layer on the root canal walls. The use of automated instruments is helpful in root canal cleaning. The aim of this study was comparison of hand NiTi instruments, rotary flexMaster and FKG race instruments in root canal cleaning. In this interventional and in vitro study, 75 single canal teeth with minimum curve were selected and divided into three groups of 25 teeth in each. The canals were prepared with hand NiTi file, FlexMaster and race instruments using crown down preparation technique, up to size 40. During preparation, the root canals were irrigated with 5m1 of 0 0.50% Naocl solution and at the end of instrumentation with 5 ml of normal saline. After splitting the roots longitudinally, the amount of the debris and smear layers were quantified on the basis of Hulsmann method, using a scanning electron microscope. The data were analyzed by Kruskal wallis test using SPSS statistical software. In general, flexMaster instruments left less debris than FKG race and NiTi hand instruments significantly [p<0.05]. This difference was significant in all three thirds of the canal. FlexMaster instruments left debris with the smallest size in the middle and coronal thirds of the canal but not the apical third. FlexMaster instruments left less smear layers just in the apical third of the canal significantly. No completely cleaned root canals were found with any of the three instruments. In general, FlexMaster instruments proved to have better canal cleaning in all three third of the root canal significantly