Efficacy of SmearOFF, maleic acid, and ethylenediaminetetraacetic acid combined with sodium hypochlorite in removal of smear layer from curved root canals: In vitro study

Introduction: Mechanical instrumentation of the root canal system produces an amorphous smear layer. The aim of the present research was to assess the effect of SmearOFF, 7% maleic acid (MA) and 17% ethylenediaminetetraacetic acid (EDTA) when combined with sodium hypochlorite (NaOCl) in removal of smear layer from curved root canals. Materials and Methods: Forty mandibular molars were selected of which only the mesial roots were prepared biomechanically and categorized into four equal groups on the basis of the irrigation protocol: (1) SmearOFF, (2) 7% MA, (3) 17% EDTA, and (4) 0.9% saline. Teeth were then decoronated; mesial roots were cleaved lengthwise and scanning electron microscopic analysis was performed for evaluation of existence of smear layer. Results: On intergroup comparison, there has been found to be notable dissimilarity among the SmearOFF and MA groups in coronal, middle and apical thirds of the root canal system (P > 0.05). However, in EDTA group, there was no notable difference in coronal and middle third. However, in apical one-third, smear layer was cleared less effectively when compared to SmearOFF and MA (P < 0.001). In contrary, all of saline group specimens were extensively smeared in all the parts of the root canal system. On intergroup comparison, all the test irrigants removed smear layer effectively in coronal and middle third of the root canal. Nonetheless, in apical portion, SmearOFF, and MA effectuated significantly better compared to EDTA. Conclusion: In combination with NaOCl, SmearOFF, and MA had superlative smear layer eradication efficacy in contrast to EDTA in apical third of the curved root canals.