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.
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.
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.
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.