Effect of three newer generation rotary files on smear layer removal using fumaric acid as an irrigant: A SEM study

BACKGROUND: To evaluate the efficacy of the smear layer removal with Fumaric acid when used in combination with new generation files Hyflex Electrical Discharge Machining (HEDM) file, Neoendo file, and Blueflex file. MATERIALS AND METHODS: Sixty extracted mandibular premolars with single-canal were selected for this study. Radiographs were taken to confirm the presence of single canal and absence of any type of calcifications, resorption, cracks, and fractures. The teeth were decoronated to a standardized length of 12 mm and working length was determined with ISO #15 K file. After this, teeth were randomly divided into 2 main groups – Control and Experimental group. In Control group, root canal instrumentation was performed with Neoendo, Blueflex, and HEDM files, respectively, along with 1 ml of 17% ethylenediaminetetraacetic acid (EDTA), and in Experimental group, root canal instrumentation was performed with Neoendo, Blueflex, and HEDM files, respectively, along with 1 ml of 0.7% fumaric acid for 1 min. Longitudinal grooves were prepared with slow-speed silicon carbide disc on the buccal and lingual surfaces of each root. Preparation for scanning electron microscope was done and phototmicrographs at ×3000 were taken. STATISTICAL ANALYSIS: The results were analyzed using ANOVA test for comparison of smear layer scores among various groups and Tukey's HSD test was used for paired comparisons of total smear layer scores. CONCLUSIONS: On the basis of the present study, Blue flex file along with fumaric acid was found to be best among the groups and Neo endo along with EDTA was the poorest.