Scanning Electron Microscopic Evaluation of Debris and Smear Layer after Use of Revo-S and CMA Instruments in Straight Root Canals

Abstract

Aim: To compare the cleanliness of root canal walls are following instrumentation with Revo-S and CMA using scanning electron microscopy SEM. Materials and Methods: 30 single-rooted human maxillary incisors with straight root canals freshly extracted for periodontal reasons were selected. Selected teeth were divided into two equal groups and prepared with Revo-S and CMA endodontic instruments. Irrigation was performed with 2.5% NaOCl, 17% EDTA solutions and final rinse with saline solution. The roots were split into two halves with a chisel and all the canals examined using SEM. The presence of debris (at 350x magnification) and smear layer (at 1500x magnification) was recorded at coronal, middle and apical thirds of root canals using a 4-point scoring system. Data were evaluated statistically using the T test of independent specimens and significance was predetermined at P<0.05. Results: None of the two groups achieved completely debrided root canals. In the coronal and middle thirds, the canal walls were clean, with no or only small areas of debris and smear layer. In the apical region, higher scores in terms of debris and smear layer were found. There were no significant differences between the two groups in smear layer and debris removal throughout the three portions of the root canal walls (P>0.05). Conclusion: In this study significant differences were not found between the root canals shaped with Revo-S and CMA NiTi rotary instruments. Both instruments produced a clean and debris-free dentine surface in the coronal and middle third, but were unable to produce dentine surfaces free from smear layer in the apical third.