Effect of Al2O3 Sandblasting Particle Size on the Surface Topography and Residual Compressive Stresses of Three Different Dental Zirconia Grades

This study investigated the effect of sandblasting particle size on the surface topography and compressive stresses of conventional zirconia (3 mol% yttria-stabilized tetragonal zirconia polycrystal; 3Y-TZP) and two highly translucent zirconia (4 or 5 mol% partially stabilized zirconia; 4Y-PSZ or 5Y-PSZ). Plate-shaped zirconia specimens (14.0 x 14.0 x 1.0 mm(3), n = 60 for each grade) were sandblasted using different Al2O3 sizes (25, 50, 90, 110, and 125 mu m) under 0.2 MPa for 10 s/cm(2) at a 10 mm distance and a 90 degrees angle. The surface topography was characterized using a 3-D confocal laser microscopy and inspected with a scanning electron microscope. To assess residual stresses, the tetragonal peak shift at 147 cm(-1) was traced using micro-Raman spectroscopy. Al2O3 sandblasting altered surface topographies (p < 0.05), although highly translucent zirconia showed more pronounced changes compared to conventional zirconia. 5Y-PSZ abraded with 110 mu m sand showed the highest Sa value (0.76 +/- 0.12 mu m). Larger particle induced more compressive stresses for 3Y-TZP (p < 0.05), while only 25 mu m sand induced residual stresses for 5Y-PSZ. Al2O3 sandblasting with 110 mu m sand for 3Y-TZP, 90 mu m sand for 4Y-PSZ, and 25 mu m sand for 5Y-PSZ were considered as the recommended blasting conditions.

Automated summary

This study investigated the effect of sandblasting particle size on the surface topography and compressive stresses of zirconia, showing that larger particles induced more compressive stresses for conventional zirconia and highly translucent zirconia was more sensitive to changes in surface topography. Recommended blasting conditions varied for different types of zirconia materials.