Cobalt-chromium alloys are commonly used in dental and reconstructive surgery due to their strength and resistance to corrosion. However, cobalt is expensive and poses potential toxicity risks. Alloys with half the cobalt replaced by iron have been available for traditionally cast crown and bridge applicances. The question the authors address is whether an alloy with reduced cobalt content can be used in additive manufacturing, specifically with the Laser Powder Bed Fusion technique.
The study compares the alloy's microstructure and mechanical properties when produced through both LPBF and traditional casting methods. Characterisation performed at the University of Stavanger of the test material produced by LPBF revealed an austenitic matrix structure and sigma-phase precipitates, which contributed to higher hardness. In testing carried out at NIOM, the alloy demonstrated strong tensile properties, good elongation, and fatigue resistance —key factors for durability in implants.
These findings suggest that the alloy can be employed for additive manufacturing, and provide a safe option for producing custom-made dental and maxillofacial appliances. The project received support from the Norwegian Research Council as part of a bilateral cooperation between Norway and India. Collaborative efforts included contributions from researchers at the Indian Institute of Technology Madras and valuable input from experts at NIOM and the University of Stavanger.
This work highlights the potential of material innovation to improve the safety, affordability, and reliability of implants used in healthcare.