Effect of Smear Layer on the Apical Seal of Endodontically Treated Teeth: An ex vivo Study

AIM: The purpose of this study was to evaluate the effect of smear layer on apical seal of endodontically treated teeth. MATERIALS AND METHODS: Sixty freshly extracted human maxillary central incisor teeth were selected and were randomly divided into two experimental groups. Group A of 25 teeth and group B of 25 teeth and a control group of 10 teeth. Cleaning and shaping of the root canals were performed using endodontic K-files up to no. 50 size file in step-back technique. During the process, in root canals of group A, 17% EDTA (ethylenediaminetetraacetic acid) followed by 3% NaOCl (sodium hypochlorite) was used as root canal irrigant. In group B, MTAD (mixture tetracycline citric acid and detergent) was used as a root canal irrigant. In control group, saline was used as root canal irrigant. The root surfaces were then coated with nail polish of both experimental groups and control group. The samples were then immersed in India ink dye for 1 week at 37°C. RESULTS: The statistical analysis of the results showed that the apical leakage was significantly more in teeth, where smear layer was not removed. CONCLUSION: The removal of smear layer improves the longterm apical seal and success of endodontically treated teeth. CLINICAL SIGNIFICANCE: The development and maintenance of apical seal is desirable and considered to be a major prerequisite to improve the outcome of root canal treatment.