Polishing dental ceramics using shear-thickening slurry

Nowadays, there is a great demand for Zirconia dental ceramics, while the existing low-cost automated polishing methods are quite limited. We propose a novel polishing methodology employing the shear-thickening slurry (STF) comprising starch and SiC abrasive particles. This polishing method enhances viscosity under applied pressure, offering an approach to address the identified challenge. A series of polishing experiments and an in vitro study are conducted to assess the effectiveness of this method compared to manual polishing. The feasibility of the proposed method for polishing dental veneer and crown ceramics is investigated as well. With 2000# SiC-STF slurry, 300 r/min fixture and 120 r/min workpiece, the minimum surface roughness Ra of polished surface can reach 9.5 nm after 30 min. Furthermore, both the novel and manual polishing methods result in samples with comparable flexural strength. Importantly, the innovative use of STF exclusively employs mechanical friction for material removal, circumventing potential chemical erosion. This work can bring a low-cost, efficient, and non-toxic automated polishing method for dental ceramics.