Effect of sandblasting and residual stress on strength of zirconia for restorative dentistry applications

Sandblasting is a commonly used surface treatment technique for dental crowns to improve the adhesion of the mating parts of a restoration. The goal of this work is to study the effect of different sandblasting conditions on the mechanical properties of 3 mol% yttria stabilized tetragonal zirconia (3Y-TZP), such as biaxial strength, surface elastic modulus, contact hardness and residual stresses induced by sandblasting. The specimens were sandblasted considering two different particle sizes (110, 250 μm), two pressures (2 and 4 bar) and two impact angles (30° and 90°). Biaxial strength of 3Y-TZP increases when sandblasted with 110 µm particles while its decreases with 250 µm particles for impact angle of 90°. Strength increases slightly when sandblasting with 30° impact angle regardless of the size of the particle. Elastic modulus and contact hardness were not affected by sandblasting with 110 µm particles, and compressive residual stresses are produced down to a depth of ~10 µm.