Antibacterial effect, cytotoxicity, and bond strength of a modified dental adhesive containing silver nanoparticles

This study aimed to evaluate the antibacterial effect, cytotoxicity, and microtensile bond strength of an adhesive system containing silver nanoparticles (NAg). NAg was synthesized and incorporated (500 and 1000 ppm) into Scotchbond Multi-Purpose (SBMP) primer and bond. A microtensile bond test (μTBS) was performed after 24 h and 1 year. The adhesive interface was characterized using a confocal Raman microscope. The antibacterial activity was assessed using agar diffusion and biofilm inhibition assays (S. mutans). MTT assay was used to assess the cytotoxicity of NAg-conditioned culture media on human dental pulp stem cells (hDPSCs). The results were statistically analyzed using analysis of variance and Tukey's tests (α = .01). Incorporating 500 and 1000 ppm of NAg in the SBMP did not affect the μTBS after 24 h (p > 0.05). However, in the 1 year evaluation, 500 ppm presented the highest μTBS values (p < 0.05). The addition of NAg at 500 and 1000 ppm in the primer and bond led to larger inhibition halos and colony-forming units than the control (p < 0.05). For the unpolymerized and polymerized groups, the combination of primer and bond presented the highest cytotoxic effects on hDPSCs (p < 0.05). In conclusion, incorporating 500 or 1000 ppm of NAg into an etch-and-rinse adhesive system led to an antibacterial effect without altering the cytotoxicity. SBMP at 500 ppm presented a higher μTBS at 1 year.