LONG-TERM DURABILITY OF COMPOSITE BONDING TO SILVER DIAMINE FLUORIDE–TREATED ENAMEL: A COMPARATIVE EVALUATION OF ETCH-AND-RINSE AND SELF-ETCH UNIVERSAL ADHESIVE STRATEGIES UNDER THERMOCYCLING AND EXTENDED WATER STORAGE

Abstract

Background: Silver diamine fluoride (SDF) is widely used for caries arrest; however, its influence on the long-term durability of composite bonding to enamel remains a clinical concern. This study evaluated the effect of etch-and-rinse and self-etch universal adhesive strategies on the bond durability of composite restorations to SDF-treated enamel following artificial aging.

Materials and Methods: One hundred extracted human premolars were randomly allocated into four groups (n = 25): Control Etch-and-Rinse, Control Self-Etch, SDF + Etch-and-Rinse, and SDF + Self-Etch. Specimens received 38% SDF application where applicable, followed by composite restoration using a universal adhesive in the designated bonding mode. All samples underwent 10,000 thermocycles and six months of water storage before shear bond strength testing and failure mode analysis.

Results: The Control Etch-and-Rinse group demonstrated the highest mean bond strength (24.82 ± 2.94 MPa), while the SDF + Self-Etch group exhibited the lowest values (17.85 ± 2.48 MPa). One-way ANOVA revealed a statistically significant difference among groups (p < 0.001). Etch-and-rinse protocols showed significantly greater bond durability than self-etch approaches, and mixed failures predominated in etch-and-rinse groups, whereas adhesive failures were more frequent in self-etch groups.

Conclusion: SDF pretreatment reduced the long-term bond strength of composite restorations to enamel; however, the etch-and-rinse universal adhesive strategy effectively mitigated this effect and demonstrated superior durability after aging. Phosphoric acid etching appears beneficial for optimizing composite bonding to SDF-treated enamel and may enhance the longevity of restorative outcomes.