Removal of calcium hydroxide from simulated internal resorption cavities with different irrigation activation methods

Objective: Ca(OH)2 has been established as the most frequently used intracanal medicament for internal resorption treatment. However, Ca(OH)2 has to be completely removed before the canal filling because any Ca(OH)2 residue on dentin walls can affect the dentinal bond strength and the penetration of sealers into the dentin tubules and cause to apical leakage. This study aimed to assess the effectiveness of XP, EA, Er, Cr: YSGG LAI, PUI techniques in removing calcium hydroxide from simulated internal resorpsion cavities. Method: Seventy five single-rooted mandibular premolar teeth were instrumented with WaveOne Gold reciprocal moving file system. The teeth were fixed in modified Eppendorf vials with silicone impression material and subsequently, teeth were split into two halves with a separator disc and internal resorption cavities were formed in the apical 1/3 region of the teeth. The teeth were reassembled, and Ca(OH)2 was delivered into the root canals with a lentulo file. The access cavities were sealed with a temporary filling material and teeth were stored at 37ºC and 100% humidity for 1 week. Then the specimens were irrigated with 5 mL %2,5 NaOCl and 5 mL %17 EDTA and the activation was performed to the teeth with EA, PUI, LAI and XP agitation methods. After the process has run out, the teeth were separated again and the presence of Ca(OH)2 in the internal root resorption cavities were assessed by stereomicroscopy. Area calculation was done with the Image J program. Results: Remnants of Ca(OH)2 in simulated internal root resorption cavities were found in all experimental groups. EA, PUI, LAI and XP were superior to CSI. There were no significant difference between these groups (P > 0,05). Conclusions: In all groups Ca(OH)2 residues remained in internal resorption cavities, Activation methods used, were found to be superior to conventional irrigation with needle. Keywords: XP-Endo Finisher, EndoActivator, PUI, Er,Cr: YSGG laser, internal root resorption, calcium hydroxide