Biostability of the Proanthocyanidins-Dentin Complex and Adhesion Studies

Area of Science:

• Biomaterials Science
• Dental Materials
• Natural Products Chemistry

Background:

• Oligomeric proanthocyanidins (OPACs) are natural bioactives derived from renewable sources.
• Standardized OPAC mixtures can be developed for biological applications.
• Dentin matrix interactions with hydrophobic adhesives on wet surfaces present adhesion challenges.

Purpose of the Study:

• To investigate the effects of an enriched grape seed extract (e-GSE) containing OPACs on dentin matrix properties.
• To evaluate the impact of e-GSE on dentin biodegradability and mechanical characteristics.
• To determine the efficacy of e-GSE in promoting resin adhesion to dentin.

Main Methods:

• Preparation of an enriched grape seed extract (e-GSE) from Vitis vinifera.
• Application of e-GSE to dentin matrices.
• Mechanical testing: 3-point flexural test, nanomechanical analysis.
• Biochemical analysis: Hydroxyproline quantification (collagen solubilization).
• Adhesion testing: Resin-dentin microtensile bond strength, micropermeability.
• Rheological analysis: Dynamic mechanical analysis (Tan δ) with urea challenge.

Main Results:

• e-GSE significantly reduced collagen solubilization in the dentin matrix.
• The elastic properties of the e-GSE-modified dentin matrix were maintained over 12 months.
• e-GSE treatment resulted in more elastic-like dentin behavior, resistant to urea-induced destabilization.
• Robust and stable adhesion was achieved at the dentin-methacrylate interface on e-GSE-primed surfaces.
• Interfacial permeability was dramatically reduced after e-GSE treatment.

Conclusions:

• Standardized OPAC mixtures, like e-GSE, offer a novel adhesion mechanism to collagen-rich tissues.
• This mechanism bypasses the need for hydrophilic monomers in dental adhesives.
• e-GSE modifies the dentin matrix, reduces biodegradation, and bridges effectively to methacrylate resins.