Bioactive luting cements on the adhesive interface of fiber post and root dentin: a comparative study of bond strength, water interaction, and enzymatic degradation.

Abstract

Objective: Innovative self-etching dental cements have been considered a versatile material with recent formulations incorporating bioactive additives. This study analyzed the role of these ingredients in systems used for luting intracanal posts.

Methodology: Bond strength (BS), water sorption (WS), water solubility (WSB), and in situ zymography (IZ) were assessed. Three cements were tested: RelyX U200 (RU, bioactive-free control), RelyX Luting Plus (RL, fluoride-containing glass-ionomer), and BeautiCem SA (BC, S-PRG-based). Bond strength was evaluated in bovine root dentin (n=10) at the cervical, middle, and apical thirds at 7 days and 6 months. WS/WSB were assessed using 10 cement disks (10×1 mm) cycled through deionized water immersion (m1), desiccation (m2), and a second immersion (m3). For IZ, the specimens (n=3) were sectioned and incubated with fluorescein-conjugated gelatin for 48h at 37°C at both storage times (7 days and 6 months) for analysis by Confocal Laser Scanning Microscopy. Fluorescence intensity was quantified using Image J. Data were analyzed using ANOVA and Tukey's test (p<0.05).

Results: RU presented the highest BS and the lowest WS/WSB, while RL showed the opposite trend. BC demonstrated intermediate performance with no statistical differences from the other materials. For all cements, the cervical third and the 6-month period yielded the highest BS values. WS/WSB were greater for the bioactive cements (BC, RL). IZ results aligned with BS findings, revealing suppressed enzymatic activity over time. Based on these results, it can be concluded that RU exhibited superior mechanical stability despite lacking bioactivity.

Conclusion: Among bioactive cements, BC emerged as an interesting alternative, offering improved bond strength, water stability, and bioactive potential compared to RL.