Effect of Silver Diamine Fluoride on Bonding Performance and Ultra-morphological Characteristics to Sound Dentin

Abstract

Objectives: This study aimed to evaluate microtensile bond strength (µTBS) and ultra-morphological characteristic changes in sound dentin resulting from silver diamine fluoride (SDF) when using adhesives. Methods: Ninety-six extracted human third molars were divided into the SDF-contaminated dentin group and the sound dentin group. In the SDF-contaminated dentin group, 38% SDF was agitated for 1 min, left undisturbed for 2 min, and rinsed with distilled water for 30 s. Then, each group was further subdivided into six subgroups (n = 8 / group) according to application modes: self-etch mode (SE) and etch-and-rinse mode (ER) followed by three adhesives: (1) Scothbond Universal Plus Adhesive (SUP); (2) G2-Bond Universal Adhesive (G2B); and (3) Clearfil Mega Bond 2 (MB2). All specimens were restored with resin composite and were stored in distilled water for 24 h before μTBS testing. Data from the μTBS test were analyzed using Three-way ANOVA and Duncan test (p < 0.05). The morphology of fractured surface and adhesive-dentin interfaces were evaluated by SEM, TEM, and STEM. Further elemental analysis was done by EDX. Results: All SDF-contaminated dentin groups demonstrated significantly lower μTBS than sound dentin groups. All ER groups had higher μTBS than SE groups, except for G2B in the sound dentin group. STEM/EDX revealed an SDF-dentin-reacted layer in the SDF-contaminated dentin group. Significance: SDF had an adverse effect on adhesives. Additionally, ER mode is preferable when bonded to SDF-contaminated dentin. A calcium and fluoride-contained layer was observed in all SDF-contaminated dentin.