Comparison of smear layer removal ability of different agitation system in the apical third of the root canal using SEM: an in vitro study

Introduction: Sodium Hypochlorite (NaOCl) remains gold standard as a result of its antimicrobial effect and tissue dissolution properties, but it has no effect on inorganic portion of smear layer. Thus the combination of NaOCl and EDTA has been proven to have the perfect ability in removal of both organic and inorganic debris. These irrigants when used with conventional syringe irrigation were unable to penetrate the apical portion of the root canal, so new activation devices have come in the market which claims to be effective in delivering the irrigant to the working length. Objective/Aim: This study evaluated and compared the efficacy of recently introduced irrigation activation devices EndoActivator, Passive ultrasonic irrigation and Laser on removal of smear layer from the apical third of instrumented root canal using Scanning electron microscope. Methods: Forty three single rooted teeth were prepared with the help of protaper files and divided into four groups. Group I: EDTA only, Group II: Endoactivator, Group III: Laser, Group IV: Passive Ultrasonic Irrigation (PUI). Three specimens were not treated with any smear layer removal protocol and were immediately sectioned and sent for SEM examination. The remaining 40 samples from 4 groups after treatment with different activation system were also sectioned and sent for SEM examination. The data obtained were statistically analysed using Friedman’s test. Results: All the four groups removed smear layer and the laser showed best smear layer removing capability compared to other groups but was significant only with respect to control and group I (EDTA group without any activation) (p<0.05). Conclusions: Within the limitations of the study, all the activation systems were able to remove the smear layer from the apical third of the root canal with laser showing the best result followed by Endoactivator and then PUI.