The influence of final endodontic irrigation techniques and irrigants on the push-out resistance of glass fiber posts.

This study evaluated the influence of different combinations of 3 final endodontic irrigation techniques (positive-pressure irrigation [PPI], passive ultrasonic irrigation [PUI], and continuous ultrasonic irrigation [CUI]) and 2 irrigants (5.25% sodium hypochlorite [NaOCl] and 2% chlorhexidine [CHX]) on the push-out resistance of glass fiber posts. Ninety bovine roots were prepared and divided into 6 groups (n = 15): PPIN, PPI with 5.25% NaOCl; PUIN, PUI with 5.25% NaOCl; CUIN, CUI with 5.25% NaOCl; PPIC, PPI with 2% CHX; PUIC, PUI with 2% CHX; and CUIC, CUI with 2% CHX. In the PPI groups, a 30-gauge needle was used to deliver the irrigating solution. In the PUI groups, a 30-gauge needle was used to deliver the irrigating solution, which was activated for 10 seconds by means of a stainless steel file mounted on an ultrasonic unit. In the CUI groups, delivery and continuous agitation of the irrigating solution for 10 seconds were performed using a stainless steel file mounted on the ultrasonic unit. After canal preparation was completed, glass fiber posts were cemented with a dual-cure resin cement. The roots were sectioned into 1-mm-thick slices (coronal, middle, and apical thirds). After 7 days' storage in distilled water, the slices were submitted to a push-out test. The mean bond strength values were compared using 2-way analysis of variance and Tukey post hoc test (P < 0.05). The mean (SD) overall bond strength values of the specimens were as follows: PPIN, 4.46 (1.43) MPa; PUIN, 6.13 (2.35) MPa; CUIN, 7.41 (1.83) MPa; PPIC, 3.59 (1.70) MPa; PUIC, 5.49 (1.41) MPa; and CUIC, 6.0 (1.63) MPa. Irrespective of the irrigating solution, continuous ultrasonic irrigation achieved significantly greater push-out bond strengths for glass fiber posts, mainly at the apical third of the root specimens (P < 0.05).
Competing Interests: The authors report no conflict of interest pertaining to any of the products or companies discussed in this article.