Abstract: | The aim of this study was to examine the smear layer removal capacity of various etidronate treatments. Seventy‐eight roots were instrumented up to apical size X4 and randomly divided into five treatment groups and a positive control group (n = 13). Groups were as follows: irrigation with 5 ml of sterile saline (control) for 3 min, 5 ml of 17% ethylenediaminetetraacetic acid (EDTA) for 3 min, 5 ml of 9% A1‐hydroxyethylidene‐1,1‐bisphosphonate (HEBP) for 3 min, 5 ml of 18% HEBP for 3 min, irrigation with 5 ml of 1% sodium hypochlorite (NaOCl) + 9% HEBP for 3 min, and 5 ml of 2% NaOCl + 18% HEBP for 3 min. The roots were examined using a scanning electron microscope. The smear layer scores in the 2% NaOCl + 18% HEBP group were lower than those in the other treatment groups and the control group (p < .05). There were no significant differences among the treatment groups in the smear layer scores of the coronal and middle thirds. However, the smear layer scores in the 2% NaOCl + 18% HEBP treatment group were lower those in the 9% HEBP and 18% HEBP treatment groups in the apical third (p < .05). In the clinical setting, the recommended concentration of HEBP is 18%, and it should be used with an oxidizing agent to ensure optimum smear layer removal. |