The repair/replacement of a missing tooth structure often involves the use of ceramic based prosthetic materials. These materials have played an important role in the dentistry field, due to their mechanic and aesthetic properties, chemical stability and biocompatibility. Additive manufacturing (AM) has emerged as new methodology to obtain long term 3D dental pieces at low cost, decreasing the materials’ waste and production time relatively to the conventional manufacturing methods. In particular, robocasting (RC), which is an extrusion filament-based 3D printing process, seems promising for this purpose.
The aim of this study is to evaluate the potential of the robocasting technique to produce reliable zirconia dental structures, comparing several properties of the samples produced by subtractive manufacturing (SM) and robocasting (AM).
Zirconia pieces produced by both methods were sintered at 1500ºC and polished. Density, porosity, Vickers hardness, toughness and roughness were evaluated. Chewing simulation tests against dental cusps were performed using artificial saliva as lubricant. The wear was quantified and the wear mechanisms investigated.
SM samples present a density similar to the theoretical value, while AM samples present a lower value, which may be attributed to the higher porosity of these samples. AM samples present higher roughness than SM samples, but lower hardness and toughness. After the chewing simulation tests, no wear was found for both SM and AM samples, the cusps suffered a significant volume reduction, which was higher for the SM samples.
In conclusion, although robocasting is a promising technique to produce dental pieces, there are still some challenges to overcome, in particular relatively to material’s densification. The samples’ porosity may affect the materials’ mechanical properties, like toughness.