Effect of Silver Diamine fluoride Containing Potassium Iodide and Nano-Hydroxyapatite on Shear Bond Strength of Nano-Hybrid Composites

Abstract

Objective: This in-virto study evaluated the effect of applying DHS treatments on immediate and long-term shear bond-strength (SBS) of nano-hybrid composite restorations. Method: Ninety non-carious extracted human molars were embedded in acrylic resin. Teeth were randomly divided into 3 main groups (n=30), according to surface treatment: 1) no treatment (control), 2) silver diamine fluoride with potassium iodide (Riva Star) and 3) nano- hydroxyapatite (PrevDent). Each group received universal adhesive followed by cylindrical composite restorations. Groups were divided into 2 sub-groups according to the time of test: 1) immediate (24 hours after the restoration) and 2) thermocycled (5000 cycles, 5°C to 55°C). Specimens were tested using a universal testing machine. Stereomicroscope was used to evaluate the mode of failure. One-way analysis of variance (ANOVA) followed by Tukey post hoc with 95 percent significance were preformed to evaluate the data. Result: The highest mean value was recorded in control immediate group (27.10 MPa) and the lowest was in SDF/KI thermocycled group (6.87 MPa). A statistically significant difference was found between the values of all groups except between nHAp immediate and control thermocycled. For control and nHAp groups majority of specimens had mixed failure, while adhesive failure was recorded among SDF/KI groups. Conclusion: The application of SDF/KI prior to bonding reduces the SBS under the minimum bond strength to resist contraction forces of resin composite materials, and the SBS values of nHAp application prior to bonding meets the minimum required bond strength to resist contraction forces of resin composite, 17-20 MPa.