Aim: The aim of this study was to evaluate the smear layer removal ability of three different irrigation solutions and their effect on calcium ion loss and dentin microhardness.
Materials and Methods: Forty root samples were used in this study. Samples were divided into four groups according to the type of irrigant used as a final rinse into: group A; 5.25% Sodium hypochlorite (NaOCl) (control), group B; 17% Ethylenediamine tetraacetic acid (EDTA), group C; QMix 2in1, and group D; 0.2% Chitosan. After final rinse the measurement of Ca ions loss was done using atomic absorption spectrophotometry. Then, samples were divided longitudinally into two halves. One half of each sample was evaluated for smear layer removal ability using Environmental Scanning Electron Microscope. The other half was examined for dentin microhardness using Vickers microhardness tester. Parametric data were analyzed by One Way ANOVA test then, Games-howell test and Tukey post-hoc test and none parametric data were analyzed by Kruskal-Wallis and Dunn's test at P ≤ 0.05.
Results: NaOCl did not show any smear layer removal ability, while EDTA, QMix, and Chitosan showed complete smear layer removal and patent dentinal tubules particularly at the cervical third. EDTA, QMix, and Chitosan recorded the highest Ca ion loss and the lowest microhardness than NaOCl.
Conclusion: EDTA, QMix, and Chitosan significantly removed smear layer and so released higher amount of Ca ion which adversely affect the microhardness. It remained difficult to completely remove smear layer from the apical third and so it recorded the highest microhardness.