Removal of calcium hydroxide intracanal medicament by different irrigants and irrigating techniques: a cone beam computed tomography analysis.

The aim of this study was to use cone beam computed tomography (CBCT) to evaluate the removal of calcium hydroxide (Ca[OH]2) from root canals after using different irrigation and activation protocols. Root canals (n = 128) were filled with Ca(OH)2 and scanned using CBCT. The Ca(OH)2 was removed after 1 week using 1 of 12 groups (G1-G12) according to the final irrigating solution: G1, 6% sodium hypochlorite (NaOCl) + 18% etidronic acid (EA) with no activation; G2, NaOCL + EA + passive ultrasonic irrigation (PUI); G3, NaOCl + EA + Finishing File (FF); G4, NaOCl + EA + NaviTip FX irrigation needle (NTFX); G5, 3% NaOCl + 17% ethylenediaminetetraacetic acid (EDTA) with no activation; G6, NaOCl + EDTA + PUI; G7, NaOCl + EDTA + FF; G8, NaOCl + EDTA + NTFX; G9, 3% NaOCl with no activation; G10, NaOCl + PUI; G11, NaOCl + FF; G12, NaOCL + NTFX. The amount of residual Ca(OH)2 was assessed by CBCT. Group comparisons were performed using 1-way analysis of variance and Student-Newman-Keuls post hoc test (P = 0.05). Group 7 showed the least residual Ca(OH)2 (10.83%), which was not significantly different from G6 (13.79%) (P > 0.05). The percentage of residual Ca(OH)2 found in these 2 groups was significantly less than that found in the other groups (P < 0.05). None of the protocols could completely remove Ca(OH)2 from the root canal system, but the plastic rotary FF and PUI, in conjunction with NaOCl and EDTA, removed significantly more Ca(OH)2 than the other irrigation activation protocols tested.