Influence of Irrigation Sequence on the Adhesion of Root Canal Sealers to Dentin: A Fourier Transform Infrared Spectroscopy and Push-out Bond Strength Analysis

Introduction: There is a lack of evidence on the chemical interaction between sealers and dentin. The influence of irrigation on the chemical interaction between root canal sealers and dentin was analyzed by using Fourier transform infrared spectroscopy (FTIRS) and measurement of dislocation resistance. Methods: Single-rooted teeth (n = 120) were instrumented with 3% NaOCl as the irrigant and divided into 4 groups (n = 30) on the basis of irrigation protocol: group 1, 3% NaOCl, 17% EDTA, water; group 2, 17% EDTA, 3% NaOCl, water; group 3, 3% NaOCl, QMix, water; group 4, 3% NaOCl, water. Each group was divided into 3 subgroups (n = 10) on the basis of the root canal sealer: A, epoxy resin (AH Plus); B, silicone (RoekoSeal); C, calcium hydroxide (Sealapex). The dislocation resistance was assessed by using push-out bond strength test. The data were statistically analyzed by three-way analysis of variance and Holm-Sidak tests (P = .05). Dentin powder treated as per the conditioning protocols mentioned was mixed with the sealers and analyzed by FTIRS. Results: A significant interaction was observed between irrigation protocol, type of sealer, and root segment (P < .001) for AH Plus but not for RoekoSeal and Sealapex (P > .05). AH Plus showed the highest bond strength (P < .05). FTIRS showed chemical bonding between AH Plus and dentinal collagen. In groups 2 and 4, no chemical bonding was observed. Conclusions: Bond strength of sealers is differentially. affected by the irrigation protocol. The epoxy resin sealer AH Plus chemically bonds to dentinal collagen. This interaction is influenced by the irrigation protocols.