Evaluation of the effect of duration of application of Smear Clear in removing intracanal smear layer: SEM study

Abstract

Aim: To evaluate the effect of duration of application of 17% ethylene diamine tetraacetic acid (EDTA) and SmearClear on the removal of intracanal smear layer by SEM. Materials and Methods: Seventy-two extracted maxillary incisors were root canal instrumented and randomly distributed into three groups of 24 teeth each according to different final irrigation regimens, Group A-17% EDTA + 1% sodium hypochlorite (NaOCl), Group B-SmearClear + 1% NaOCl, Group C (Control group)-Distilled water + 1% NaOCl. Further each group was subdivided into 3 subgroups according to the duration of application of the irrigating solutions for 1, 3 and 5 minutes. Following de-coronation and splitting of roots, one-half of each root was examined under scanning electron microscope (SEM) at 1000Χ magnification for smear layer at 6 mm and 2 mm levels. Data were subjected to statistical analysis using Kruskal-Wallis and Mann-Whitney U test (P < 0.05) Results: At 6 mm level, the mean smear scores were similar with both 17% EDTA solution and Smear Clear, however, at 2 mm level, they were significantly lower with Smear Clear (P < 0.05). The smear scores decreased as the duration of application of either 17% EDTA or Smear Clear increased from 1 to 5 minutes. Conclusion: Final irrigation with either 17% EDTA solution or Smear Clear followed by 1% NaOCl was effective in removing the smear layer for all three durations of applications. But, in the apical third, Smear Clear was more effective when compared with 17% EDTA solution.