Evaluation of smear layer removing with chemical and fizical methods: SEM analysis

BACKGROUND: Crucial action during the endodontic therapy is canal disinfection and elimination of smear layer. The aim of the paper was to make evaluation of smear layer elimination with EDTA and Nd: YAG laser. MATERIAL AND METHOD: 60 single root human teeth extracted from prosthetic or orthodontic reasons were included in this study. After removal of the crowns of teeth endodontic treatment was realized. According to the method of removing the smear layer teeth were divided into two groups: in the first group of 30 teeth, after the final irrigation we had used 17% EDTA for 2 minutes, and in the second group of 30 teeth 8 sec. irradiation with Nd: YAG laser was used. After the elimination of smear layer, all examined teeth were longitudinally cut and prepared for SEM analysis, in coronary, middle and apical third of the root. RESULTS: The elimination of smear layer is an important procedure in the endodontic therapy and multiple methods can be used for that. The results of our research showed that both methodologies are effective for smear layer elimination. EDTA solution efficiently and simpler in combination with irrigation successfully eliminates smear layer in the coronary and middle third of the root of the tooth. Nd: YAG laser is successful method for sterilization of channel space but requires specific equipment. CONCLUSION: Both methods are effective for removing smear layer but the choice still depends from the pulp disease, the endodontic treatment itself and from the selection and the decision of the therapist