The objective of this work was to analyze the in vitro and in vivo tests of a novel Mg-based biodegradable alloy—Mg-0.5%Ca—with various amounts of Zn (0.5, 1, 1.5, 2.0, and 3.0 wt.%). In terms of in vitro biocompatibility, MTT and Calcein-AM cell viability assays, performed on the MG-63 cell line through the extract method, revealed that all five alloy extracts are non-cytotoxic at an extraction ratio of 0.025 g alloy per mL of cell culture medium. In the in vivo histological analysis, Mg-0.5Ca-1.5Zn demonstrated exceptional potential for stimulating bone remodeling and showed excellent biocompatibility. It was observed that Mg-0.5Ca-0.5Zn, Mg-0.5Ca-1.5Zn, and Mg-0.5Ca-3Zn displayed good biocompatibility. Furthermore, the histological examination highlighted the differentiation of periosteal cells into chondrocytes and subsequent bone tissue replacement through endochondral ossification. This process highlighted the importance of the initial implant’s integrity and the role of the periosteum. In summary, Mg-0.5Ca-1.5Zn stands out as a promising candidate for bone regeneration and osseointegration, supported by both in vitro and in vivo findings.

Background: This study examined how the concentration of calcium (Ca) influences the microstructure, mechanical characteristics, and tribological attributes of Mg–Ca–Zn–RE–Zr alloys for orthopedic medicine. Materials and methods: Experimental alloys with 0.1 and 0.5 wt% Ca were prepared in a controlled atmosphere induction furnace. The microstructure of the alloys was investigated by scanning electron microscopy, the chemical composition by X-ray fluorescence and energy-dispersive spectroscopy, the mechanical properties by indentation and scratching, and the corrosion resistance by linear and cyclic potentiometry. Results: The alloy with 0.1% Ca exhibited greater fluctuations in the coefficient of friction, while the sample with 0.5% Ca showed a higher susceptibility to cracking. Regarding corrosion resistance, both samples exhibited a generalized corrosion trend with similar corrosion currents. At lower Ca concentrations (0.1%), the refined microstructure of the alloys provided an elastic modulus closer to that of human bone, minimizing the risk of excessive local stress and promoting uniform load distribution at the bone-implant interface. Conclusion: The 0.5% Ca alloy offered superior tribological stability and better shock absorption, making it suitable for applications requiring long-term stability. The study highlighted the potential of both compositions based on the specific requirements of biodegradable orthopedic implants.

The ideal biomaterial used in endodontics in the process of sealing the radicular canals should possess a group of qualities for a predictable outcome: biocompatibility, initiation of ontogenesis and cementogenesis, ease of handling, sufficient manipulation time, and convenient price. For a perfect sealing, the root canal treatment can be followed by prosthetic restoration. This study of biocompatibility aims to determine the quantification of the local reaction following the implantation of three biomaterials in the rabbit subcutaneous connective tissue. The used biomaterials with particular reparative properties are: MTA (Mineral Trioxide Aggregate, Dentsply, Tulsa Dental, Johnson City, TN, USA), Sealapex (Kerr, Switzerland), and DiaRoot BioAggregate (Innovative BioCaramix Inc, Vancouver, BC, Canada). The first two biomaterials (MTA, Sealapex) are already being used in endodontic treatments, and the latter was newly introduced during the concrete development of the study. This is an experimental study focused on qualitative and quantitative analysis based on histopathological examination and underlined by the positive result of the study undertaken of the applicability of oral rehabilitation treatments, increasing patients’ quality of life by a significant proportion of 95%, and generating optimal functionality of the stomatognathic system with prosthetic devices as well as accomplishing the objectives of homeostasis.

Biodegradable alloys in Mg have the advantages of traditional metallic materials and those of biodegradable polymers with superior strength, lower density and ideal rigidity for fixing bone fractures. The biocompatibility and biodegradability of the five concentrations of Mg-0.5Ca-xZr alloys used were assessed using clinical and laboratory examinations that followed over time: tissue reaction, histological and imaging (RX, CT and SEM) evolution at 1, 2, 4 and 8 weeks after implant. The main purpose of this study was to investigate in vivo the long-term effect of Mg-0.5Ca-xZr alloys in rats. The results confirmed that Mg-0.5Ca-xZr alloys are biocompatible and biodegradable and are recommended to be used as possible materials for new orthopedics devices.

Mg-based biodegradable materials, used for medical applications, have been extensively studied in the past decades. The in vitro cytocompatibility study showed that the proliferation and viability (as assessed by quantitative MTT-assay—3-(4,5-dimethyltiazol-2-yl)-2,5-diphenyl tetrazolium bromide) were not negatively affected with time by the addition of Mn as an alloying element. In this sense, it should be put forward that the studied alloys don’t have a cytotoxic effect according to the standard ISO 10993-5, i.e., the level of the cells’ viability (cultured with the studied experimental alloys) attained both after 1 day and 5 days was over 82% (i.e., 82, 43–89, 65%). Furthermore, the fibroblastic cells showed variable morphology (evidenced by fluorescence microscopy) related to the alloy sample’s proximity (i.e., related to the variation on the Ca, Mg, and Mn ionic concentration as a result of alloy degradation). It should be mentioned that the cells presented a polygonal morphology with large cytoplasmic processes in the vicinity of the alloy’s samples, and a bipolar morphology in the remote region of the wells. Moreover, the in vitro results seem to indicate that only 0.5% Mn is sufficient to improve the chemical stability, and thus the cytocompatibility; from this point of view, it could provide some flexibility in choosing the right alloy for a specific medical application, depending on the specific parameters of each alloy, such as its mechanical properties and corrosion resistance. In order to assess the in vivo compatibility of each concentration of alloy, the pieces were implanted in four rats, in two distinct body regions, i.e., the lumbar and thigh. The body’s reaction was followed over time, 60 days, both by general clinical examinations considering macroscopic changes, and by laboratory examinations, which revealed macroscopic and microscopic changes using X-rays, CT(Computed Tomography), histology exams and SEM (Scanning Electron Microscopy). In both anatomical regions, for each of the tested alloys, deformations were observed, i.e., a local reaction of different intensities, starting the day after surgery. The release of hydrogen gas that forms during Mg alloy degradation occurred immediately after implantation in all five of the groups examined, which did not affect the normal functionality of the tissues surrounding the implants. Imaging examinations (radiological and CT) revealed the presence of the alloy and the volume of hydrogen gas in the lumbar and femoral region in varying amounts. The biodegradable alloys in the Mg-Ca-Mn system have great potential to be used in orthopedic applications.

The medical field has undergone constant development in recent years, and a segment of this development is occupied by biodegradable alloys. The most common alloys in this field are those based on Mg, their main advantage being the ability to degrade gradually, without affecting the patient, and also their ability to be fully absorbed by the human body. One of their most important conditions is the regeneration and replacement of human tissue. Tissue can be engineered in different ways, one being tissue regeneration in vivo, which can serve as a template. In vivo remodeling aims to restore tissue or organs. The key processes of tissue formation and maturation are: proliferation (sorting and differentiation of cells), proliferation and organization of the extracellular matrix, biodegradation of the scaffold-remodeling, and potential tissue growth. In the present paper, the design of the alloys in the Mg-Ca-Y system is formed from the beginning using high-purity components, Mg-98.5%, master-alloys: Mg-Y (70 wt.%–30 wt.%) and Mg-Ca (85 wt.%–15 wt.%). After 8 weeks of implantation, the degradation of the implanted material is observed, and only small remaining fragments are found. At the site of implantation, no inflammatory reaction is observed, but it is observed that the process of integration and reabsorption, over time, accentuates the prosaic surface of the material. The aim of the work is to test the biocompatibility of magnesium-based alloys on laboratory rats in order to use these alloys in medical applications. The innovative parts of these analyses are the chemical composition of the alloys used and the tests performed on laboratory animals.