Phosphoric Acid Etch Partially Restores the Initial Bond Strength of Composite to Silver Diamine Fluoride–Treated Enamel Using Universal Adhesives

Background: Restoring bonding composite to silver diamine fluoride (SDF)-treated enamel is challenging. This study investigates if phosphoric acid etch restores bond strength SDF-treated using universal adhesives. Methods: Twenty-four recently extracted permanent teeth were randomly divided into 4 (2 experimental (SDF) and 2 control (CTR)) groups: SDF+Water: SDF (1 min) then water rinse (15 mL); CTR+Water: no treatment SDF+Etch+Water: min), 35% (40 s) CTR+Etch+Water treatment, mL). The surface in all the groups was bonded (All-Bond Universal) 4–5 mm blocks (Z-250). Each sample sectioned, 6–8 beams × 1 mm) selected. micro-tensile measured by dividing force peak adhesive area. Univariate ANOVA Chi-square used for between-group comparisons with p < 0.05. Results: SDF+Water had significantly lower tensile compared (p 0.05). Although difference found between SDF+Etch+Water CTR+Etch+Water, more failures = 0.047). Conclusions: While seems restore initial enamel, long-term success of restorations may need further investigation.