Comparison of smear layer removal ability using different protocols for the final rinse optimization

Aim. This study aimed to compare the efficacy of Tetraclean and 17% EDTA as final irrigants in the removal of the smear layer in the coronal, middle and apical thirds of the instrumented root canal. Methods. Forty extracted human permanent teeth (n =10) were randomly assigned to the following groups: (1) control group, the root canals were not submitted to any smear layer removal procedure, (2) EDTA group, (3) Liquid Tetraclean group (only liquid component of Tetraclean), (4) Tetraclean group, (powder + liquid). The specimens were submitted to scanning electron microscopy analysis. Magnifications of 500X and 1000X were used to evaluate cleaning at the apical, middle, and cervical thirds according to a three-point scoring system. Data were statistically analyzed using the Kruskal-Wallis analysis of variance test (5% significance level). Results. When the entire canal was considered, groups were ranked in the following order: 1>2≥3=4 (p<0.05). For different sections of the canal space, distance from the apex (2, 6 and 10 mm) influenced smear layer removal within each group (p<0.05). Conclusions. The use of a chelating agent leads to a higher removal of smear layer from the root canal walls. Differences between EDTA and Tetraclean were only evident at 6 mm from the apex, whereas at 2 mm both protocols had similar performances in smear layer removal from the root canal system of single-rooted permanent teeth.