The efficacy of 5% maleic acid, 6% phosphoric acid and 17% EDTA in smear layer removal - a scanning electron microscopic investigation

. Smear layer is amorphous irregular layer that contains inorganic dentin debris and organic material such as pulp tissue, odontoblastic processes, necrotic debris and microorganisms. It is present on root canal walls touched by instruments during instrumentation. The aim of this study was to compare the efficacy of 6% Phosphoric acid, 17% EDTA and 5% Maleic acid in smear layer removal using scanning electron microscope analysis. Material and Methods. The study included eighty extracted teeth. All teeth were randomly assigned into the three experimental groups (17% EDTA, 5% Maleic acid, 6% Phosphoric acid) and one control group (sodium hypochlorite). Smear layer removal in all groups in apical, middle, and coronal thirds was observed using scanning electron microscope analysis. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests. Also, Friedman and Wilcoxson tests were used to compare different sections in each group (a=0.05, SPSS ver. 15). Results. There was no significant difference observed between three experimental groups. All tested irrigants were capable of removing smear layer (p>0.05). Also, there was a significant difference between different regions of root canals in all experimental groups except in phosphoric acid group. Conclusion. The effectiveness of EDTA, Maleic acid and Phosphoric acid is comparable and all of them are efficient in removing smear layer.