Influence of continuous chelation on the push-out bond strength of epoxy resin and calcium silicate sealers in oval root canals.

Abstract

Objectives: To compare the push-out bond strength (POBS) of AH Plus and TotalFill BC Sealer in long oval canals prepared with the Self-Adjusting File Infinitum (SAF Infinitum) system.

Materials and methods: Thirty mandibular canines with long oval canals, selected by micro-CT analysis and anatomically matched, were assigned to three irrigation-protocol groups (n = 10): 2.5% NaOCl (4 min, 4 mL/min); 2.5% NaOCl/HEDP (4 min, 2 mL/min); and 2.5% NaOCl/HEDP (2 min, 2 mL/min). Each group was subdivided by sealer (AH Plus or TotalFill BC Sealer, n = 5) and filled using the single-cone technique. Roots were sectioned into coronal, middle, and apical slices for POBS testing and failure mode analysis. POBS was analyzed using a Gamma generalized linear mixed-effects model with a log link and tooth as a random intercept, followed by Bonferroni-adjusted pairwise comparisons (α = 0.05).

Results: Neither irrigation protocol (P = 0.879) nor sealer (P = 0.769) significantly affected POBS, and no two- or three-way interactions were significant (all P > 0.7). In contrast, POBS differed significantly across root thirds (P < 0.001), with higher values in the apical than in the coronal (P = 0.001) and middle thirds (P < 0.001), and higher in the coronal than in the middle third (P = 0.005). Adhesive failure at the sealer-gutta-percha interface predominated overall (80% AH Plus, 93% TotalFill BC) and was universal in the middle third.

Conclusions: In long oval canals prepared with SAF Infinitum, POBS differed significantly according to root third but not according to sealer type or irrigation protocol.

Clinical relevance: When the SAF Infinitum system is used with a single-cone filling technique, short-term POBS does not appear to differ according to the irrigation protocol or sealer type under the conditions tested. Sealer and irrigation choices may therefore be guided by other biological and clinical considerations rather than by short-term push-out bond strength alone.