Structural, Physical, and Mechanical Analysis of ZnO and TiO2 Nanoparticle-Reinforced Self-Adhesive Coating Restorative Material

This study aimed to modify an EQUIA coat (EC; GC, Japan) by incorporating 1 and 2 wt.% of zinc oxide (ZnO; EC-Z1 and EC-Z2) and titanium dioxide (TiO2; EC-T1 and EC-T2) nanoparticles, whereby structural and phase analyses were assessed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. Thermogravimetric analysis/differential scanning calorimetry, micro-hardness, and water absorption analyses were conducted, and the microstructure was studied by scanning electron microscopy/energy-dispersive spectroscopy. FTIR spectra showed a reduction in peak heights of amide (1521 cm(-1)) and carbonyl (1716 cm(-1)) groups. XRD showed peaks of ZnO (2 theta ~ 31.3 degrees, 34.0 degrees, 35.8 degrees, 47.1 degrees, 56.2 degrees, 62.5 degrees, 67.6 degrees, and 68.7 degrees) and TiO2 (2 theta ~ 25.3 degrees, 37.8 degrees, 47.9, 54.5 degrees, 62.8 degrees, 69.5 degrees, and 75.1 degrees) corresponding to a hexagonal phase with a wurtzite structure and an anatase phase, respectively. Thermal stability was improved in newly modified materials in comparison to the control group. The sequence of obtained glass transitions was EC-T2 (111 degrees C), EC-T1 (102 degrees C), EC-Z2 (98 degrees C), EC-Z1 (92 degrees C), and EC-C (90 degrees C). EC-T2 and EC-T1 showed the highest (43.76 +/- 2.78) and lowest (29.58 +/- 3.2) micro-hardness values. EC showed the maximum water absorption (1.6%) at day 7 followed by EC-T1 (0.82%) and EC-Z1 (0.61%). These results suggest that EC with ZnO and TiO2 nanoparticles has the potential to be used clinically as a coating material.

Automated summary

This study aimed to modify an EQUIA coat by incorporating zinc oxide and titanium dioxide nanoparticles, and various analyses showed improved thermal stability, hardness, and reduced water absorption in the modified materials. The results suggest that EC with ZnO and TiO2 nanoparticles has the potential to be used clinically as a coating material.