Adesivos autocondicionantes com biovidro 45S5 funcionalizados com clorexidina: Avaliação da resistência de união e nanoinfiltração ao longo do tempo

Abstract

Adhesive systems play a fundamental role in restorative procedures, but their durability can be compromised by the degradation of the hybrid layer due to the activity of collagenolytic enzymes, such as MMPs. Strategies to improve the longevity of adhesive interfaces include the use of bioactive particles, such as 45S5 bioglass, which promotes remineralization and functionalization with drugs. The aim of this study was to evaluate the bond strength and nanoleakage pattern of an experimental self-etching adhesive system containing 45S5 bioglass particles functionalized with chlorhexidine. Materials and methods: Experimental self-etching adhesive systems containing 45S5 bioglass particles functionalized or not with chlorhexidine, at different concentrations (5% and 20%), were evaluated using 48 human third molars. Bond strength was tested 24 hours and after 6 months, and nanoleakage was analyzed with silver nitrate and SEM. A commercial adhesive system and an experimental adhesive system without particles were used as controls. Statistical analysis included Two-Way ANOVA and Holm-Sidak test (α = 0.05). Results: Bond strength tests to dentin revealed significant differences between the immediate and six-month evaluation times (p < 0.001), with no significant interaction between adhesive type and time (p = 0.526), indicating that the performance of the adhesives followed similar trends. Aging reduced bond strength in all adhesives tested. Nanoleakage analysis indicated a significant interaction between adhesive and time (p = 0.016), with the 45S5 5% adhesive showing improvement after 6 months, outperforming the control (p < 0.05), while 45S5 20% showed worsening. 45S5 CHX 5% also outperformed 45S5 20%, evidencing the influence of composition and storage time on nanoleakage. Conclusions: Although the bond strength values to dentin were similar between the groups, the experimental adhesive 45S5 5% demonstrated greater stability in the nanoleakage test after six months, highlighting its potential as a bioactive material to improve the durability of resin-dentin interfaces. Functionalization with chlorhexidine also contributed positively, reinforcing its viability to inhibit interface degradation over time.