J Korean Acad Prosthodont.  2014 Apr;52(2):67-73. 10.4047/jkap.2014.52.2.67.

Comparison of the mechanical properties and microstructures of fractured surface for Co-Cr alloy fabricated by conventional cast, 3-D printing laser-sintered and CAD/CAM milled techniques

  • 1Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, Republic of Korea. young21c@snu.ac.kr
  • 2Department of Dental Biomaterials Science, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
  • 3US Army Carius Dental Clinic, Dentac-Korea, 618th Dental Command, Seoul, Republic of Korea.


The purpose of present study is to compare mechanical properties and microstructural characteristics of fractured surface for cast, 3-D printing laser sintered and CAD/CAM milled cobalt-chromium (Co-Cr) alloy specimens and to investigate whether laser sintered technique is adequate for dental applications.
Thirty six flat disc shape Co-Cr alloy specimens were fabricated for surface hardness test and divided into three groups according to the manufacturing methods; 12 specimens for casting (n=12), 12 specimens for laser sintered technology (n=12) and 12 specimens for milled technology (n=12). Twelve dumbbell shape specimens for each group were also fabricated for a tensile test. Statistical comparisons of the mechanical properties for the alloys were performed by Kruskal-Wallis test followed by Mann-Whitney and Bonferroni test. The microstructural characteristics of fractured surfaces were examined using SEM.
There were significant differences in the mean Vickers hardness values between all groups and the cast specimen showed the highest (455.88 Hv) while the CAD/CAM milled specimen showed the lowest (243.40 Hv). Significant differences were found among the three groups for ultimate tensile strength, 0.2% yield stress, elongation, and elastic modulus. The highest ultimate tensile strength value (1442.94 MPa) was shown in the milled group and the highest 0.2% yield strength (1136.15 MPa) was shown in the laser sintered group.
Different manufacturing methods influence the mechanical properties and microstructure of the fractured surfaces in Co-Cr alloys. The cast Co-Cr alloy specimens showed the highest Vickers hardness, and the CAD/CAM milled specimens revealed the highest tensile strength value. All alloys represent adequate mechanical properties satisfying the ISO standards of dental alloy.


Co-Cr alloys; CAD/CAM dental; Dental laser sintering; Mechanical property; Microstructure

MeSH Terms

Dental Alloys
Elastic Modulus
Hardness Tests
Tensile Strength
Dental Alloys
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