The performance of silver diamine fluoride on bond strength and ultramorphology of universal adhesive to artificial carious dentin under thermocycling conditions

Abstract

Objectives: To investigate the effect of silver diamine fluoride (SDF) on the microtensile bond strength (µTBS) and resin-dentin interface of universal adhesive (etch-and-rinse mode) under thermocycling. Materials and methods: Artificial caries lesions were induced on human dentin discs using a bacterial model and divided into four groups: C (no treatment), CT (no treatment, thermocycling), CS (SDF), and CST (SDF, thermocycling). The treated-dentin surface was bonded with universal adhesive (etch-and-rinse mode) and stored for 24 h or subjected to 10,000 thermocycles. µTBS was performed with 1 mm/min crosshead speed with a 50 N load cell (n = 16/group). The resin-dentin interface was examined using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) (n = 3/group). Statistical analyses included two-way ANOVA with Bonferroni post-hoc tests for µTBS and Fisher’s Exact Test with Bonferroni correction for failure mode distribution. Results: The highest bond strength was observed in C (24.28 ± 2.27 MPa) followed by CST (18.26 ± 5.63 MPa). Significantly lower µTBS was detected in CS (14.20 ± 3.32 MPa) and CT (12.72 ± 2.12 MPa). CT exhibited a distinct failure mode from the other groups (p < 0.05). CLSM revealed less uniform resin tags in CS and CST. EDX demonstrated silver deposition at 50 μm beneath the adhesive layer in CS and at 120 μm with lower intensity in CST. Conclusions: SDF enhances bonding durability, as evidenced by increased µTBS and modified resin-dentin interface. Clinical relevance: SDF may enhance the durability of bonding with universal adhesive in etch-and-rinse mode.