Scanning Electron Microscopy Evaluation of the Smear Layer Removal Using Various Chelating Agents - An invitro Study

This in-vitro study was conducted to evaluate the efficiency of removal of smear layer from apical, middle & coronal part of the root canal system using three chelating agents. Sixty extracted single-rooted human teeth were randomly divided into 4 groups (n -15) and instrumented using protaper nickel-titanium rotary instruments. The following solutions were used to irrigate each canal subsequently: 5.25% NaOCl (control), SmearClear, 17% EDTA and 10% citric acid. Then the specimens were subjected to final irrigation with 5.25% NaOCl. Following de-coronation and splitting of roots, one-half of each root was examined under scanning electron microscope (SEM) at 1000X and 2000X magnification for smear layer at coronal, middle, and apical thirds. The results showed that there was difference in the effectiveness of three chelating agents in smear layer removal however the result was not clinically significant (p<0.0005). The protocol used in this study showed better smear layer removal in the coronal and middle third when compared to apical third.