Effects of interactions between sealers and irrigants on the physicochemical and surface characteristics of endodontic sealers

Objectives: Endodontic irrigants, including chlorhexidine digluconate (CHX) and sodium hypochlorite (NaOCl), are commonly used and may interact chemically with root canal sealers, affecting their physicochemical properties and surface structure. This study evaluated the effects of clinically relevant irrigation solutions on the physicochemical and microstructural properties of the epoxy resin-based AH Plus Jet (AHP) and calcium silicate-based AH Plus Bioceramic (AHPB) sealers. Materials and methods: Sealers were placed in Teflon molds, and irrigants (2% CHX, 2.5% NaOCl, or 0.9% saline) were applied to the top surface of each specimen before incubation at 37 °C and 95% relative humidity for 72 h. Physicochemical properties (setting time, microhardness, solubility, dimensional change), chemical properties (ion release, pH changes), and surface characteristics (scanning electron microscopy (SEM)–energy-dispersive X-ray spectroscopy, contact angle) were assessed following the ISO 6876:2012 standard. Additional analyses were conducted after immersion in Hank’s balanced salt solution (HBSS) for 28 days. Statistical analysis included one-way ANOVA, paired t-tests, and repeated measures ANOVA. Results: Exposure to irrigants significantly prolonged the setting times of both AHP and AHPB. AHP exhibited significantly increased solubility beyond ISO standards and showed reduced microhardness after NaOCl exposure. AHPB demonstrated high solubility exceeding ISO standards under all tested conditions, particularly after CHX exposure. Both sealers maintained dimensional changes in accordance with ISO requirements. AHPB demonstrated significantly reduced calcium ion release following CHX and NaOCl exposure yet maintained high alkalinity (pH > 10). After 28 days of immersion, SEM analysis revealed uniform spherical precipitates on AHPB surfaces in the saline and control groups, whereas CHX- and NaOCl-exposed groups showed irregular deposits. In addition, CHX exposure significantly reduced contact angles on AHP surfaces after aging. Conclusions: CHX and NaOCl affected the physicochemical properties of both sealers. AHP was most affected by NaOCl, exhibiting delayed setting, reduced hardness, and increased solubility. AHPB was primarily influenced by CHX and NaOCl, showing increased solubility, reduced calcium ion release, and retention of irrigants on its surface, while element concentration and alkalinity were not affected by sealer–irrigant interactions. Clinical relevace: The choice of final irrigant can substantially influence the performance of root canal filling materials. Understanding sealer–irrigant interactions can help clinicians choose combinations that optimize sealing efficacy and long-term treatment success.