Evaluation of the bond strength of three different restorative materials to silver fluoride–treated carious dentin

Objective: This study aimed to evaluate the shear bond strength and fracture types of three fluoride-releasing restorative materials. The materials were applied to sound dentin, artificially demineralized dentin, and artificially demineralized dentin that had been treated with silver fluoride (SF) solution, both with and without artificial aging. Materials and Methods: Dentin from 180 extracted primary molars, either caries-free or with enamel caries, was used. Three restorative materials (a high-viscosity glass ionomer cement, a resin-modified glass ionomer cement, and an alkasite restorative material) were applied to sound dentin, artificially demineralized dentin, and artificially demineralized dentin treated with SF solution. Following restoration, half of the specimens in each group were subjected to 500 thermal cycles (55 ± 5 °C). Shear bond strength was measured, and fracture types were determined by examining the debonded surfaces under a stereomicroscope. Additionally, one specimen from each group was analyzed by SEM at magnifications of ×100, ×500, ×1000, and ×2500. Results: In both aged and non-aged groups, irrespective of the restorative material, the bond strength values on sound and artificially demineralized dentin were similar (p>0.05); however, the lowest bond strength was observed in artificially demineralized dentin treated with silver fluoride (p<0.05). On sound and artificially demineralized dentin, Cention Forte exhibited significantly higher values than Fuji IX and Fuji II LC (p<0.05). No significant difference was found among the materials in the silver fluoride–treated group. Regarding the effect of aging, higher values were observed in aged specimens for Fuji IX and Fuji II LC, and in non-aged specimens for Cention Forte, when bonded to sound dentin. For artificially demineralized dentin, higher values were observed in non-aged specimens for Fuji IX and Cention Forte, and in aged specimens for Fuji II LC. In the silver fluoride–treated group, a significant difference between aged and non-aged subgroups was detected only for Fuji II LC and Cention Forte (p<0.05). Failure modes were predominantly adhesive and mixed, with no significant differences between groups (p>0.05). Conclusion: Although Cention Forte demonstrated significantly higher bond strength compared to other glass ionomers on both sound and artificially demineralized dentin in both short- and long-term evaluations, its bond strength decreased significantly after SF application. Fuji IX was the least affected material by SF treatment.