Zirconia dental pieces produced by robocasting have higher porosity and roughness

Zirconium oxide ZrO2 or zirconia is an oxide ceramic, usually found as a white powder. It is a high-performance ceramic with many applications. Zirconia has the particularity to present a monoclinic crystal structure at room temperature and tetragonal and cubic at a higher temperature. Once shaped and sintered, this hard technical ceramic offers high performance for many applications in various fields such as dentistry, refractories, electrical insulation, abrasive tools, or automotive due to its excellent mechanical properties both at room temperature and high temperature.

Zirconia can be combined with other materials and elements. Alumina toughened zirconia (ATZ) is one of those materials where a small fraction of alumina is added to zirconia to improve its mechanical properties significantly.

This study aims to evaluate the tribological performance of the pair of human teeth/robocasted zirconia, focusing on the enamel wear mechanisms. Zirconia pieces produced by robocasting (RC) and unidirectional compression (UC) were compared in terms of crystalline structure, density, porosity, hardness and toughness. Chewing simulation tests were performed against human dental cusps. The cusps wear was quantified, and the wear mechanisms were identified. Although most of the properties of UC and RC samples are similar, differences were observed in surface roughness and porosity. Although the samples did not suffer wear, the antagonist cusps worn similarly.

In conclusion, robocasting seems a promising technique to produce customized zirconia dental pieces, which concerns the overall tribological behaviour.

Reference:

Tribological performance of the pair human teeth vs 3D printed zirconia: An in vitro chewing simulation study by A.C.Branco et al. published in the Journal of the Mechanical Behavior of Biomedical Materials

https://doi.org/10.1016/j.jmbbm.2020.103900