The influence of sodium hypochlorite and root canal sealers on post retention in different dentin regions

This study evaluated the influence of 5.25% NaOCl irrigant and root canal sealers on post retention in different dentin regions. Seventy-two human incisors were decoronated at the cemento-enamel junction and randomly divided into six groups (n=12) according to irrigant and sealer technique: G1-Distilled water (DW) without sealer; G2-DW + AH Plus (Dentsply/Maillefer); G3-DW + Endofill (Dentsply/Maillefer); G4-5.251%NaOCl without sealer; G5-5.25% NaOCl + AH Plus; G6-5.25% NaOCl + Endofill. Specimens were stored in a humid environment for 30 days at 37 degrees C and were prepared with FRC Postec's drills for post insertion. The posts were cemented with Excite DSC/Variolink II (Ivoclar/Vivadent). The specimens were sectioned through their long axis into three dental slices approximately 2.5 mm each, representing the cervical (C), middle (M) and apical (A) thirds of the root preparation. After calculating the adhered area of the specimens, they were submitted to the push-out test in a universal testing machine. The data were submitted to an analysis of variance (ANOVA) at a 5% significance level and to the Tukey test (p<0.05). The mean values (MPa) obtained for cervical, middle and apical areas of the root preparation, respectively, were: G1=8.6; 12.5 and 14.3, G2=13.5; 15.4 and 16.9; G3=6.9; 10.0 and 12.1; G4=13.0; 14.9 and 15.4; G5=11.3; 13.5 and 18.0; and G6=11.0; 11.8 and 11.5. Based on the results, the eugenol-based sealer (Endofill) resulted in significantly lower mean retention strength values compared with the resin-based sealer (AH Plus). The apical region showed the greatest retention. The lowest resistance to dislodgment was found in the cervical region, mainly in the groups that used distilled water for irrigating the root canal.