Effect of customized bioactive glass in experimental composites on dentin bond strength after 12 months of aging.

Abstract

Objectives: This study aimed to investigate the effect of a customized low-sodium bioactive glass (BG) fillers in experimental resin composites on their bond strength to dentin after 12 months of artificial aging. Specifically, it evaluated whether the bond strength was affected by different BG concentrations (0, 10, 20, 40 wt%) and artificial aging durations (1, 6, and 12 months).

Materials and methods: Experimental composites were prepared with 10, 20, and 40 wt% of a customized low-sodium fluoride-containing BG. The experimental composite with 0 wt% BG was used as a control, while Beautifil II (Shofu) was used as an external reference material. A universal adhesive system was applied to dentin substrates and composite build-ups were made. Bond strength was measured using a macro-shear bond strength test, and Weibull statistics were used to assess the reliability of the materials. Failure modes were analyzed to evaluate the type of the fracture.

Results: After 12 months, the bond strength of all experimental composites remained stable and comparable to the control material, with statistically significant improvements between 6 and 12 months for all experimental materials. The bond strength was statistically similar across materials, except at the 12-month point, where the 20 wt% BG-composite showed significantly higher bond strength than the 40 wt% BG-composite. The frequency of mixed failures in composite increased after 12 months, particularly in experimental composites containing higher BG content.

Conclusions: The incorporation of a customized low- sodium BG into resin composites did not negatively impact their bond strength to dentin over 12 months. Instead, bond strength improved over time, and the composites remained mechanically stable, although a higher incidence of mixed failures was observed with increased BG content.

Clinical relevance: The customized low-sodium BG demonstrated stable bond strength over the 12-month period, offering a promising option for functional fillers in restorative composites without compromising the longevity of the adhesive-dentin interface.