Dimeric Proanthocyanidins on the Stability of Dentin and Adhesive Biointerfaces

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Polymer Chemistry

Background:

• Dentin biomodification is crucial for durable dental restorations.
• Proanthocyanidins (PACs) show potential for reinforcing dentin and improving adhesion.
• Understanding structure-activity relationships of PACs is key to optimizing their efficacy.

Purpose of the Study:

• To investigate the sustained biomodification and bioadhesion of specific B-type PAC dimer fractions (DIMER_G, DIMER_NG) and their precursor (e-GSE).
• To evaluate the long-term effects on dentin's mechanical properties and collagen stability.
• To assess the impact on dentin-resin bond strength and interface durability.

Main Methods:

• Fractionation of grape seed extract to isolate PAC dimers.
• Long-term evaluation of apparent modulus of elasticity and collagen solubility (hydroxyproline release).
• Attenuated total reflectance-Fourier-transform infrared spectroscopy for chemical characterization.
• Microtensile bond strength testing and assessment of resin conversion.

Main Results:

• All tested PAC fractions (DIMER_G, DIMER_NG, e-GSE) increased modulus of elasticity and reduced collagen degradation.
• DIMER_NG demonstrated superior stability over 12 months compared to DIMER_G and e-GSE.
• Dentin treated with e-GSE showed higher bond strength, with all interfaces remaining stable after 12 months.
• PAC treatments did not affect resin conversion but induced cross-linking in the dentin matrix.

Conclusions:

• Nongalloylated PACs provide stable dentin biomodification, protecting against collagen degradation and reinforcing the dentin matrix.
• Higher PAC oligomerization enhances bioadhesion between hydrophilic dentin and hydrophobic adhesives.
• Specific PAC fractions offer promising strategies for improving the longevity and performance of dental restorations.