Suitability of 3D printed pieces of nanocrystalline zirconia for dental applications. Issue 3 (March 2020)

• Record Type: Journal Article
• Authors: Branco, A.C.; Silva, R.; Santos, T.; Jorge, H.; Rodrigues, A.R.; Fernandes, R.; Bandarra, S.; Barahona, I.; Matos, A.P.A.; Lorenz, K.; Polido, M.; Colaço, R.; Serro, A.P.; Figueiredo-Pina, C.G.
• Is Part Of: Dental materials. Volume 36:Issue 3(2020)
• Page Start: 442
• Page End: 455
• Publication Date: 2020-03
• Subjects: 3D printing/additive manufacturing -- Robocasting -- Dental material -- Zirconia -- Wear; Dentistry -- Periodicals; Dental materials -- Periodicals; 617.695
• DOI: 10.1016/j.dental.2020.01.006
• Languages: English
• ISSNs: 0109-5641

Abstract

Graphical abstract: Highlights: Zirconia dental pieces were produced by robocasting (AM) and subtractive manufacturing (SM). AM samples revealed to be biologically safe and present adequate properties. AM samples are more porous, less hard and tough and more hydrophilic than SM samples. Although both samples do not suffer wear on chewing simulation, cusps wear less against AM. Glazing of both samples led to a dramatic increase of the antagonist cusps wear. Abstract: Objectives: The main goal of this work is to evaluate the suitability of nanostructured zirconia pieces obtained by robocasting additive manufacturing (AM), for dental applications. Methods: The density, crystalline structure, morphology/porosity, surface roughness, hardness, toughness, wettability and biocompatibility of the produced samples were compared with those of samples obtained by conventional subtractive manufacturing (SM) of a similar commercial zirconia material. Chewing simulation studies were carried out against dental human cusps in artificial saliva. The wear of the material was quantified and the wear mechanisms investigated, as well as the influence of glaze coating. Results: AM samples, that revealed to be biocompatible, are slightly less dense and more porous than SM samples, showing lower hardness, toughness and wettability than SM samples. After chewing tests, no wear was found both on AM and SM samples. However, the dental wear was significantly lower when AM samples were used as counterbody. Concerning the glazed samples, both coated surfaces and dental cusps suffered wear, being the cusps' wear higher than that found for unglazed samples. More, cusps tested against AM coated samples suffered less wear comparatively to those opposed to SM coated samples. Significance: Overall, the results presented in this paper show that AM processed nanostructured zirconia can be used in dental restorations, with important advantages from the point of view of processing and tribological performance. Moreover, the option for glaze finishing should be carefully considered both in SM and AM processed specimens.