Influence of Non-Staining Chitosan-Based Nano-Silver Fluoride on Shear Bond Strengths of Dental Restorations

Objective: To investigate the influence of chitosan-based nano-silver fluoride (CNSF) treatment of tooth tissues on shear bond strength (SBS) of resin composite (RC) and resin-modified glass ionomer (RMGI) restorations. Methods: 90 extracted human molars were collected. Specimens were randomly assigned to three groups (n = 30): non-pretreated (NPT) pretreated with either CNSF or silver diamine fluoride (SDF). Each group was subdivided into two restorative subgroups (n = 15): RC and RMGI. Specimens in CNSF and SDF groups were pretreated with CNSF or SDF per their manufacturer’s instructions. Then specimens in RC subgroups were etched, treated with chlorhexidine cleanser, followed by adhesive application. Specimens in RMGI subgroups were treated with cavity conditioner only. A cylindrical restoration (2.38 mm θ × 2 mm height) of RC or RMGI restoration was fabricated with a standardized mold and light-cured on all specimens. After 5000 times of thermocycling between 5 °C and 55 °C with dwell times of 30 s intervals, SBS was measured using the Ultradent UltraTester. Data was analyzed statistically (α = 0.05) using ANOVA/Tukey’s comparisons. Results: No statistically significant difference in SBS among RC restorations in the three treatment groups: NPT (17.48 ± 3.96), CNSF (18.38 ± 5.59), and SDF (14.03 ± 6.56). For RMGI restorations, SBS was significantly (p < 0.05) higher in NPT (15.99 ± 3.59) compared to CNSF-treated (11.45 ± 5.48), but there was no significant difference between NPT and SDF-treated (14.27 ± 2.17) or between SDF- and CNSF-treated groups. Conclusions: No difference in SBS of resin composite restorations when the dentin tissue is pretreated with either chitosan-based nano-silver fluoride or silver diamine fluoride. However, SBS of RMGI was lowered when the dentin tissue was pretreated with CNSF.