Physicochemical characterization of etch-and-rinse adhesive system doped with catechin-loaded polymeric microparticles.

Abstract

This study evaluated the incorporation of epigallocatechin-3-gallate (EGCG)-loaded poly(lactide-co-glycolide) (PLGA) microparticles into a two-step etch-and-rinse adhesive and their effects on physicochemical properties and EGCG release. EGCG was added to Single Bond 2 either directly (0.01% and 0.1% w/w) or encapsulated in PLGA 50:50 or 75:25 microparticles (0.5%-2% w/w). Cumulative release was measured by UV-Vis spectrophotometry. Degree of conversion (DC) was analyzed by Fourier transform infrared spectroscopy; flexural strength and elastic modulus (E) were tested in three-point bending; and water sorption (WS) and solubility (SL) were evaluated following ISO standards (n = 10). Microtensile bond strength (TBS) was tested after 24 h, 6, and 12 months. Data were analyzed by anova with significance set at p < 0.05. PLGA 50:50/EGCG at 1% showed the highest release, reaching 77.30 µg. No significant differences were found in DC, E, WS, and SL among the groups. Bond strengths remained stable in all experimental groups after 6 and 12 months, except for the control. Incorporating 1% EGCG-loaded PLGA 50:50 microparticles into Single Bond 2 may represent a promising strategy for controlled release without compromising physicochemical or mechanical properties.