Comparative evaluation of removal of smear layer using newer rotary endodontic files: A scanning electron microscope study

AIM: The aim of this study is to evaluate the smear layer removal efficacy of newer rotary files using scanning electron microscopic analysis at the coronal, middle, and apical third of the root canal. MATERIALS AND METHODS: In this study, sixty permanent human single-rooted teeth with complete, mature root apices without any anatomic variation having straight patent root canal extracted for periodontal cause were included. The samples were cleaned to remove debris, calculus and rinsed with sodium hypochlorite to remove organic tissue and then stored in distilled water. All the samples were decoronated with the help of carborundum disc at root length of 12 mm to obtain segments similar in length. After this, all the samples were randomly divided into four groups -Protaper universal, Protaper Gold, EDM, and Revo-S. After cleaning and shaping, samples in each group were finally flushed with normal saline. Samples were then dried. Grooves were made into the root in the buccal and lingual portion of the root using a diamond bur and the samples were split longitudinally into two halves using stainless steel chisel and mallet. Preparation for scanning electron microscope was done and phototmicrographs at ×3000 were taken. RESULT: Chi square test and Kruskal–Wallis test was used for statistical analysis. Result of this study showed that Revo –S was found to be best amongst the groups and EDM was the poorest. CONCLUSIONS: Based on the present study, Revo-S files showed the best smear layer removal in the coronal, middle, and apical 1/3(rd) of the root canal when compared to other groups. Within the parameters of the study, Revo –S was found to be best amongst the groups and EDM was the poorest. The quality of various files according to ranks of smear layer removal was found to be: Group IV > Group II > Group I > Group III.