Nano Biomedicine
ORIGINAL ARTICLE

Evaluation of Cytotoxicity and Cellular Morphology Induced by Cobalt-Chromium Alloy Fine Powder for Dental 3D Printing

Yuqing HUANG1, Shizuo HIGUCHI2, Satoshi FUJITA2, Mariko NAKAI3, and Koichi IMAI4


1Graduate School of Health Sciences, 2Department of Oral Health Engineering,
Faculty of health Sciences,
3Department of Forensic Dentistry, 4Department of Tissue Engineering, School of Dentistry,
Osaka Dental University, Osaka, Japan
Nano Biomed 2025; 17(2): 116-122, (Dec 30, Nano Biomedicine)
Synopsis
Particles with diameters below 4 µm were isolated from cobalt–chromium alloy (Co-Cr) powders used in 3D additive manufacturing, and their effects on Balb/c 3T3 mouse fibroblasts were evaluated after four days of exposure. Cytotoxicity was evaluated using the MTT and neutral red uptake (NR) assays, and cell morphology was examined by scanning electron microscopy (SEM).
The MTT assay revealed a modest reduction in cell viability in the Co-Cr-exposed group compared with the particle-free control group, and comparable findings were obtained with the NR assay. However, in both assays the reduction in cell viability was minimal, indicating the absence of marked cytotoxicity. In contrast, SEM observations revealed surface irregularities and intracellular particle uptake, indicating morphological changes at the cellular level.
These findings suggest that Co-Cr microparticles of several micrometers in size can influence cell morphology while exerting only limited effects on cell viability. The biological behavior and in vivo impact of such particles remain poorly understood; nevertheless, even micron‑sized particles, similar to nanoscale or submicron powders, may pose potential biological risks in dental laboratory environments where Co-Cr alloy powders are handled, highlighting the importance of appropriate protective measures.

Key words: cobalt-chromium, 3D printing, cytotoxicity, cellular morphology, microparticles
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DOI: 10.11344/nano.17.116

Huang Y, Higuchi S, Fujita S, Nakai M, Imai K. Evaluation of cytotoxicity and cellular morphology induced by cobalt-chromium alloy fine powder for dental 3D printing. Nano Biomed 2025; 17: 116-122.