Bond Strength to Gutta-Percha of a Novel Phase-Stable Epoxy Resin Sealer Compared With Six Endodontic Sealers

Aim: To evaluate the bond strength of the reformulated epoxy resin-based sealer AH Plus Ribbon to gutta-percha using a previously described microshear bond strength test, and to compare its performance with that of six commercially available endodontic sealers representing different chemical classes. Methodology: One hundred and forty gutta-percha discs (10 mm × 2 mm) were fabricated from standardized sheets and randomly allocated to seven groups (n = 10 microshear specimens per group, assembled from 20 discs) according to the sealer evaluated: AH Plus Ribbon, AH Plus, EndoSequence BC Sealer, NeoSealer Flo, Pulp Canal Sealer, Endomethasone N and Sealapex. A standardized volume of sealer (0.1 mL) was placed between two gutta-percha discs under a constant load (0.0981 N) for 200 s. After storage at 37°C for 7 days in contact with phosphate-buffered saline-moistened gauze, microshear bond strength was determined using a universal testing machine at a crosshead speed of 0.5 mm/min. Bond strength values (MPa) were analysed by one-way ANOVA and Tukey's HSD post hoc test (α = 0.05). Results: No premature failures occurred during specimen preparation, storage, or testing. Sealer type significantly influenced bond strength to gutta-percha (p < 0.001). AH Plus Ribbon and AH Plus exhibited the highest bond strengths and did not differ significantly from each other (p = 0.722). Pulp Canal Sealer and Endomethasone N showed intermediate bond strength, whereas EndoSequence BC Sealer, NeoSealer Flo and Sealapex exhibited the lowest values, with no significant differences among them (p > 0.05). Conclusions: AH Plus Ribbon exhibited bond strength to gutta-percha comparable to that of AH Plus and significantly higher than that of EndoSequence BC Sealer, NeoSealer Flo, Pulp Canal Sealer, Endomethasone N and Sealapex under the experimental conditions employed.