Effect of layered manufacturing techniques, alloy powders, and layer thickness on mechanical properties of Co-Cr dental alloys

• Published in: The Journal of prosthetic dentistry Vol. 120; no. 5; pp. 762 - 770
• Main Authors: Ucar, Yurdanur, Ekren, Orhun
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2018
• Subjects: Chromium Alloys - chemistry; Dental Materials - chemistry; Dentistry; Hot Temperature; In Vitro Techniques; Lasers; Materials Testing; Powders; Surface Properties
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1016/j.prosdent.2017.11.032

The popularity of direct metal laser sintering (DMLS) and melting (DMLM) has increased in dental practice. The layered manufacturing device, the alloy powder, and the layer thickness may affect the mechanical properties of layer-fabricated metals. The purpose of this in vitro study was to evaluate the mechanical, fractographic, and compositional properties of metals fabricated by using different layered manufacturing techniques (DMLS and DMLM), cobalt-chromium (Co-Cr) alloy powders, and layer thicknesses. A total of 90 dumbbell-shaped test specimens (n=15/group) were fabricated by using either DMLS or DMLM. Powder alloys used were EOS Co-Cr SP-2 and Keramit NP-S, each with layer thicknesses of 20 and 30 μm; their mechanical properties were evaluated by using a test for tensile strength. Three-way ANOVA, Student t test, and 1-way analysis of variance, followed by the Tukey honest significant differences test were used for statistical analysis (α=.05). The fracture surface was analyzed by using scanning electron microscopy, and energy dispersive spectroscopy was used for compositional evaluation. Different layered manufacturing equipment affected the mechanical properties of the final objects, but the powder and layer thickness did not affect mechanical properties. The powder and layer thickness did not affect mechanical properties of the layered manufactured alloy, but different manufacturing methods did affect the mechanical properties of the final product.