Biomodification of dentin collagen with hydroalcoholic propolis extract: Impact on resin–dentin adhesion

TL;DR

This study shows that hydroalcoholic propolis extract can improve the stability of dentin collagen and help maintain the bond between resin and dentin over time.

Contribution

The novel use of hydroalcoholic propolis extract as a collagen cross-linking agent for dentin adhesion is demonstrated.

Findings

1% hydroalcoholic propolis extract significantly improved collagen cross-linking and elastic modulus.

After 6 months, 1% HPE preserved microtensile bond strength better than lower concentrations and the control.

Fourier-transform infrared spectroscopy confirmed enhanced cross-linking in treated groups.

Abstract

This in vitro study evaluated the effect of hydroalcoholic propolis extract (HPE) as a collagen cross‐linking agent for preserving the dentin–adhesive interface. Dentin beams from human third molars were demineralized with 10% phosphoric acid and assigned to five treatments: distilled water (control), 6.5% grape seed extract (GSE), and HPE at 0.1%, 1%, or 10%. Elastic modulus (n = 10), dry mass variation (n = 10), and microtensile bond strength (µTBS, n = 8) were assessed after 24 h and after 6 months of storage. Collagen stability was analyzed using Fourier‐transform infrared spectroscopy (n = 10). Elastic modulus was evaluated using Kruskal–Wallis and Friedman tests, dry mass variation, and µTBS with linear mixed‐effects models. GSE produced the greatest increase in elastic modulus, followed by 1% and 0.1% HPE. After 6 months, all experimental groups maintained µTBS, except 0.1% HPE and the control, which showed reductions of approximately 30%. Spectroscopic analysis revealed increased Amide I and decreased Amide II bands in all treated groups, indicating enhanced collagen cross‐linking. Overall, HPE—particularly at 1%—improved dentin collagen stability and contributed to the preservation of the adhesive interface over time.

Figures