Comparative evaluation of smear layer removal efficacy using smear clear, glyde file prep, citric acid and edta - a scanning electron microscopy study

Objective: The objective of this study was to compare the efficacy of four decalcifying agents: Smear clear TM (Sybron Endo), Glyde FILE PREP (Dentsply maillefer), freshly prepared 20% Citric acid and freshly prepared 17%EDTA on smear layer removal using Scanning Electron Microscope.
Materials and Methods: Sixty extracted, non carious single rooted human premolar teeth were collected. Root canals were prepared up to Protaper F3 size. The samples were randomly divided into 4 experimental groups of 15 teeth each. Group 1- 1ml of freshly prepared 17% EDTA rinsed for 1 minute alternatively with 2ml of 3% Sodium hypochlorite between each instrument. Group 2- 1ml smear clear rinsed for 1 minute alternatively with 2ml of 3% Sodium hypochlorite between each instrument. Group 3- 1ml Glyde File Prep and 2ml of 3% Sodium hypochlorite are alternatively used between each instrument. Group 4- 1ml 20% Citric acid rinsed for 1 minute alternatively with 2ml of 3% Sodium hypochlorite between each instrument. The smear layer removal of all groups at the apical, middle, and coronal thirds was observed under the thermal field emission scanning electron microscope.
Results: The effect of smear layer removal by Smear clear was better than that of citric acid and freshly prepared 17% EDTA and Glyde File Prep in coronal and middle third. At the apical third freshly prepared 17% EDTA effectively removed smear layer than Smear clear, Glyde File Prep and 20% Citric acid.
Conclusion(s): All decalcifying agents could effectively, but not completely, remove the smear layer, especially in the apical third. The decalcifying agents were more effective in the coronal and middle thirds than in the apical third.