Cobalt–chromium (Co-Cr) alloys have been used in a wide variety of biomedical applications, including dental, cardiovascular, and orthopedic devices. In vitro studies have shown that the mineralization of cells involved in osteogenesis is regulated by boron. The development of a new cobalt-chromium-boron (Co-Cr-B) alloy improves the mechanical properties of the metal, such as wear resistance, and meets biocompatibility requirements. Therefore, the objective of this study was to evaluate the osteogenic differentiation and biocompatibility in in vitro assays. Human dental pulp mesenchymal cells (hDPSCs) were isolated from volunteers and then co-cultured with the Co-Cr plus boron alloy from 0.3% to 1% for 15 days, while the formation of calcium deposits was quantified by Alizarin red staining and the expression of genes was related to osteodifferentiation by RT-qPCR. Simultaneously, the cytotoxicity of our alloy was evaluated by MTT assay and the change in the gene expression of cytokines commonly associated with inflammatory processes. The results showed low cytotoxicity when cells were treated with the Co-Cr-B alloy, and no change in the gene expression of IL-1β, TNF-α, IL-6, and IL-8 was observed compared to the untreated control (p > 0.05). The osteoinduction results shown an increase in mineralization in hDPSCs treated with Co-Cr-B alloy with 1.0% B. In addition, a significant increase in mRNA levels for collagen type 1 in with 0.3% boron and alkaline phosphatase and Runx2 with 0.6% boron were observed. The addition of Boron to the ASTM F75 Co-Cr base alloy improves the biocompatible characteristics. No cytotoxicity and any change of the expression of the pro-inflammatory cytokines IL-1β, TNF-α, IL-6, and IL-8 in human peripheral blood mononuclear cells treated with the cobalt-chromium-boron alloy was observed in vitro assays. Furthermore, our alloy acts as an osteoinductive in osteogenic differentiation in vitro. Therefore, our results could set the standard for the development of in vivo trials and in the future, it could be considered as an alternative for regenerative therapy.

Metallic biomaterials are considered safe materials for the fabrication of orthopedic prostheses due to their mechanical stability. Among this group, cobalt-chromium-molybdenum alloys are commonly used. Nevertheless, adverse reactions on tissues caused by the liberation of metallic ions are a limitation. Therefore, the modification of biometallic material surfaces has become a topic of interest, especially the improvement of the wear resistance to retard the degradation of the surface. In this work, dimples obtained at different processing parameters by an ns-pulse laser were texturized on an ASTM F-1537 cobalt alloy. Surfaces were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy, and Raman spectroscopy. The mechanical integrity of the surface was evaluated using a 3D surface analyzer and Vickers indentation tests. The tribological response was studied employing a ball-on-disc tribometer under lubricated conditions tracking the coefficient of friction, volume loss, wear rate, and surface damage by SEM. The variation of the laser power, repetition rate, and process repetitions slightly modified the chemistry of the surface (oxides formation). In addition, the rugosity of the zone treated by the laser increased. The texturized samples decreased the wear rate of the surface in comparison with the untreated samples, which was related to the variation of the dimple diameter and dimple depth.