Additively Manufactured Commercial Co-Cr Dental Alloys: Comparison of Microstructure and Mechanical Properties.

Dalibor Viderščak,Zdravko Schauperl,Črtomir Donik,Aleksandra Kocijan,Sanja Šolić,Amir Ćatić,Irena Paulin,Matjaž Godec

doi:10.3390/ma14237350

Dalibor Viderščak, Zdravko Schauperl + Show 6 more

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https://doi.org/10.3390/ma14237350

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Abstract

Laser-powder bed fusion (LPBF) is one of the preferred techniques for producing Co-Cr metal structures for dental prosthodontic appliances. However, there is generally insufficient information about material properties related to the production process and parameters. This study was conducted on samples produced from three different commercially available Co-Cr dental alloys produced on three different LPBF machines. Identically prepared samples were used for tensile, three-point bending, and toughness tests. Light microscopy (LM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) analyses of microstructure were performed after testing. Differences were observed in microstructures, which reflected statistically significant differences in mechanical properties (one-way analysis of variance (ANOVA) and Scheffé post hoc test (α = 0.05)). The material produced on the 3D Systems DMP Dental 100 had 24 times greater elongation ε than the material produced on the Sysma MySint 100 device and the EOS M100 machine. On the other hand, the material produced on the EOS M100 had significantly higher hardness (HV0.2) than the other two produced materials. However, the microstructure of the Sysma specimens with its morphology deviates considerably from the studied group. LPBF-prepared Co-Cr dental alloys demonstrated significant differences in their microstructures and, consequently, mechanical properties.

Highlights

Manufactured (AM) Co-Cr-based alloys are used for metallic structures of dental appliances and generally for biomedical purposes
The mechanical properties of Co-Cr specimens made on Sysma MySint 100, EOS M100, and 3D Systems DMP Dental 100 are comparable or even better than the mechanical properties of Co-Cr specimens produced by the conventional routes, which are casting and milling (CNC) technologies
The results of the current study demonstrate that the tested specimens meet at least the type 5 criteria in mechanical properties according to the EN ISO 22674:2016 (Rp0.2 ≥ 500 MPa and ε ≥ 2%), except the Sysma Mysint100 specimens for elongation ε

Summary

Introduction

Manufactured (AM) Co-Cr-based alloys are used for metallic structures of dental appliances and generally for biomedical purposes. Due to their excellent mechanical properties with a combination of high wear, corrosion resistance, and biocompatibility, Co-Cr alloys are one of the standard materials in biomedical applications. Co-Cr alloys for dental appliances demonstrate optimal manufacturing, biomedical, and economic characteristics [1,2]. Just a few studies are available that investigate the impact of the production parameters and machine set-up for AM production on the quality and mechanical characteristics of dental metal-based constructions for fixed partial dentures (FPDs) [4,5]

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