Effect of sandblasting conditions on alumina retention in representative dental alloys

This study determined the effect of grit size and application pressure on alumina fragment retention after sandblasting in representative dental alloys. Plastic rectangular patterns (25x3x0.6 mm, n=240) were divided equally into four groups and cast with Au-Pt, Ni-Cr, Co-Cr alloys and grade-II cp-Ti. The specimens from each alloy were then divided into 12 subgroups. Each subgroup was then sandblasted with one of the 12 possible combinations of grit size (50, 100 and 250 microns) and propulsion pressure (0.15, 0.30, 0.45 and 0.60 MPa), and their surfaces imaged and analyzed using SEM/EDS analysis. The Al composition was statistically analyzed by two-way ANOVA with Tukey's post-test. Materials tested showed a substantial amount of retained alumina fragments, the extent of which was dependent on the grit size and propulsion pressure applied for tested alloys except cp-Ti. Importantly, sandblasting conditions different from those proposed by the manufacturers achieved lower levels of retained alumina fragments.