Effects of Zn-Doped Mesoporous Bioactive Glass Nanoparticles in Etch-and-Rinse Adhesive on the Microtensile Bond Strength

The purpose of this study was to assess the effects in the dentin bond strength of dental adhesives (DAs) and biological effects using zinc (Zn)-doped mesoporous bioactive glass nanoparticles (MBN-Zn). Synthesized MBN and MBN-Zn were characterized by scanning electron microscopy (SEM), X-ray diffraction and the Brunauer, Emmett and Teller (BET) method. The matrix metalloproteinases (MMP) inhibition effects of DA-MBN and DA-MBN-Zn were analyzed. The microtensile bond strength (MTBS) test was conducted before and after thermocycling to investigate the effects of MBN and MBN-Zn on the MTBS of DAs. The biological properties of DA-MBN and DA-MBN-Zn were analyzed with human dental pulp stem cells (hDPSCs). Compared with the DA, only the DA-1.0% MBN and DA-1.0% MBN-Zn exhibited a statistically significant decrease in MMP activity. The MTBS values after thermocycling were significantly increased in DA-1.0% MBN and DA-1.0% MBN-Zn compared with the DA (p < 0.05). It was confirmed via the MTT assay that there was no cytotoxicity for hDPSCs at 50% extract. In addition, significant increases in the alkaline phosphatase activity and Alizarin Red S staining were observed only in DA-1.0%MBN-Zn. These data suggest the 1.0% MBN and 1.0% MBN-Zn enhance the remineralization capability of DAs and stabilize the long-term MTBS of DAs by inhibiting MMPs.