Influence of Bioactive Desensitizers on Bonding of Self-adhesive Resin Cement: A SEM/EDX Microanalysis Study

Abstract

Introduction: Bioactive desensitizing agents are increasingly used to alleviate dentin hypersensitivity; however, their impact on the bonding performance of self-adhesive resin cements remains unclear. This in vitro study evaluated the effect of bioactive desensitizers on the bond strength of a self-adhesive resin cement to dentin and examined elemental changes on the dentin surface using Energy-Dispersive X-ray (EDX) spectrometry.

Methods: Dentin surfaces of extracted molars were exposed and treated with a glutaraldehyde-based desensitizer (Dentin Desensitizer; DD), a calcium phosphate-based desensitizer (Teethmate Desensitizer; TM), a hydroxyapatite-based desensitizer (Predicta Bioactive; PB), or fluoride gel (APF Fluoride Gel; FL). The control group received no treatment. Self-adhesive resin cement (Panavia SA Cement Universal) was applied in cylindrical molds. After thermocycling, microshear bond strength was measured, and failure modes were analyzed. Scanning Electron Microscopy (SEM) combined with EDX analysis was performed to assess changes in the dentin surface.

Results: The DD group showed the highest bond strength (11.15 ± 1.32 MPa), followed by PB (5.98 ± 1.79 MPa), the control group (5.08 ± 1.17 MPa), and FL (4.78 ± 0.75 MPa). TM showed the lowest value (4.09 ± 0.52 MPa). ANOVA with post-hoc comparisons confirmed significant differences, with DD outperforming all other groups (p < 0.001). Adhesive failure was the most common, followed by mixed-type failures. EDX results indicated increased mineral and decreased carbon content across all treated groups, most notably in the PB group.

Discussion: Although bioactive desensitizers altered dentin composition, their inconsistent effect on bond strength may be attributed to the distinct microstructural changes each induces.

Conclusion: Clinicians must carefully consider the balance between enhancing patient comfort and preserving the long-term integrity of the restoration.