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Titanium alloys have emerged as the most successful metallic material to ever be applied in the field of biomedical engineering. This comprehensive review covers the history of titanium in medicine, the properties of titanium and its alloys, the production technologies used to produce biomedical implants, and the most common uses for titanium and its alloys, ranging from orthopedic implants to dental prosthetics and cardiovascular devices. At the core of this success lies the combination of machinability, mechanical strength, biocompatibility, and corrosion resistance. This unique combination of useful traits has positioned titanium alloys as an indispensable material for biomedical engineering applications, enabling safer, more durable, and more efficient treatments for patients affected by various kinds of pathologies. This review takes an in-depth journey into the inherent properties that define titanium alloys and which of them are advantageous for biomedical use. It explores their production techniques and the fabrication methodologies that are utilized to machine them into their final shape. The biomedical applications of titanium alloys are then categorized and described in detail, focusing on which specific advantages titanium alloys are present when compared to other materials. This review not only captures the current state of the art, but also explores the future possibilities and limitations of titanium alloys applied in the biomedical field.

ObjectiveThis review paper aims to provide a comprehensive understanding of the historical evolution of dental biomaterials, as well as to understand the reasons behind their biocompatibility and to identify the key factors that have influenced their development and use over the past 5000 years.Data sourcesThe sources for this review were primarily obtained through Scopus and other online databases, such as Google Scholar, which were searched for relevant publications spanning clinical, archeological, and materials science literature. In cases where no other sources were available, information was gathered through consultation with museums and owners of private collections.Study selectionOur search was conducted using specific materials and ages as keywords and, for the last two centuries, retrieving scientific articles written at that time of the first development and commercialization. When possible, secondary sources such as literature reviews were prioritized, while not peer-reviewed documents were utilized only when no other sources were available. References with varying perspective and findings were included, also when presented contradictory or controversial information.ConclusionsIn this review, clinical, archeological and chemical data could be merged into a comprehensive analysis of the historical evolution of the concept of biocompatibility in dental materials. The results of this review emphasize the significant advances that have been made in the field of dental biomaterials in terms of biocompatibility, from the use of gold and other metals in ancient civilizations to the development of modern materials such as resin composites and ceramics.Clinical significanceBy analyzing the development and use of dental biomaterials over the centuries from clinical, archeological and chemical perspectives, the review sheds light on the key factors that have shaped our understanding of biocompatibility in dental materials and the importance of this concept in the success of dental restorations.

This review explores the critical role of powder quality in metal 3D printing and the importance of effective powder recycling strategies. It covers various metal 3D printing technologies, in particular Selective Laser Melting, Electron Beam Melting, Direct Energy Deposition, and Binder Jetting, and analyzes the impact of powder characteristics on the final part properties. This review highlights key challenges associated with powder recycling, including maintaining consistent particle size and shape, managing contamination, and mitigating degradation effects from repeated use, such as wear, fragmentation, and oxidation. Furthermore, it explores various recycling techniques, such as sieving, blending, plasma spheroidization, and powder conditioning, emphasizing their role in restoring powder quality and enabling reuse.

The history of metallic orthopedic materials spans a few centuries, from the use of carbon steel to the widespread adoption of titanium and its alloys. This paper explores the evolution of these materials, emphasizing their mechanical properties, biocompatibility, and the roles that they have played in improving orthopedic care. Key developments include the discovery of titanium’s osseointegration capability, the advent of porous coatings for osseointegration, surface modifications, and the rise of additive manufacturing for patient-specific implants. Beyond titanium, emerging materials such as biodegradable alloys, tantalum, zirconium, and amorphous metals are creating a completely new field of application for orthopedic metals. These innovations address longstanding challenges, including stress shielding, corrosion, and implant longevity, while leading the way for bioresorbable and 3D-printed patient-specific solutions. This paper concludes by examining future trends and their potential for industrial application. By understanding the historical developments in metallic orthopedic materials, this review highlights how past advancements have laid the foundation for both current and future innovations, guiding research towards solutions that better mimic the properties of biological tissues, offer higher reliability in vivo, and enable patient-specific treatments.

The effect of yttria content on structural and thermal stability of zirconia in yttria-stabilized zirconia (YSZ) polycrystalline ceramics was systematically investigated by Raman spectroscopy and X-ray photoelectron spectroscopy. Taking advantage of an experimentally retrieved linear dependence of Raman bandwidth on yttria content, Raman imaging was applied as an effective tool in examining the local yttrium distribution in YSZ ceramics and its relationship with environmentally driven polymorphic transformation. A significant variation of monoclinic fraction with yttria content and temperature was found and interpreted according to a newly proposed model, which takes into account the change in lattice hydroxyl and oxygen vacancies and the possible formation of stable defect complexes.

This paper presents the earliest documented evidence for the presence and consumption of horse meat in Early Bronze Age Sicily, significantly revising previous understandings of equid use on the island. Multidisciplinary analyses involving proteomics and lipidomics were performed on ceramic vessels from the Castelluccian settlement at Polizzello Mountain (Caltanissetta), revealing residues consistent with equine-derived substances. Proteomic data unequivocally identified equine serum albumin in multiple pottery fragments, demonstrating active consumption or processing of horse-derived substances within a ceremonial or dietary context. Lipid residues further supported this interpretation, indicating the presence of animal fats and vegetable-derived substances within the pottery. These findings substantially alter existing models of horse domestication, utilization, and dietary practices in prehistoric Sicily, suggesting a far earlier and more complex human-equid relationship. Furthermore, the integration of biomolecular data enhances our understanding of intercultural interactions, ritual behaviors, and economic strategies in the central Mediterranean during the third millennium BCE.

While the reciprocity between bioceramics and living cells is complex, it is principally governed by the implant’s surface chemistry. Consequently, a deeper understanding of the chemical interactions of bioceramics with living tissue could ultimately lead to new therapeutic strategies. However, the physical and chemical principles that govern these interactions remain unclear. The intricacies of this biological synergy are explored within this paper by examining the peculiar surface chemistry of a relatively new bioceramic, silicon nitride (Si 3 N 4 ). Building upon prior research, this paper aims at obtaining new insights into the biological interactions between Si 3 N 4 and living cells, as a consequence of the off-stoichiometric chemical nature of its surface at the nanometer scale. We show here yet unveiled details of surface chemistry and, based on these new data, formulate a model on how, ultimately, Si 3 N 4 influences cellular signal transduction functions and differentiation mechanisms. In other words, we interpret its reciprocity with living cells in chemical terms. These new findings suggest that Si 3 N 4 might provide unique new medicinal therapies and effective remedies for various bone or joint maladies and diseases.

In the current study, high-temperature stability was investigated in two types of zirconia ceramics stabilized with two different additives, namely, calcia and yttria. The evolutions of structure and oxygen-vacancy-related defects upon annealing in air were investigated as a function of temperature by combining X-ray diffractometry with Raman, X-ray photoelectron and cathodoluminescence spectroscopies. We systematically characterized variations in the concentration of oxygen vacancies and hydroxyl groups during thermal treatments and linked them to structural alterations and polymorphic transformation. With this approach, we clarified how the combined effects of different dopants and temperature impacted on structural development and on the thermal stability of the oxygen-vacancy-related defect complex.

Surface inactivation of human microbial pathogens has a long history. The Smith Papyrus (2600 ~ 2200 B.C.) described the use of copper surfaces to sterilize chest wounds and drinking water. Brass and bronze on doorknobs can discourage microbial spread in hospitals, and metal-base surface coatings are used in hygiene-sensitive environments, both as inactivators and modulators of cellular immunity. A limitation of these approaches is that the reactive oxygen radicals (ROS) generated at metal surfaces also damage human cells by oxidizing their proteins and lipids. Silicon nitride (Si 3 N 4 ) is a non-oxide ceramic compound with known surface bacterial resistance. We show here that off-stoichiometric reactions at Si 3 N 4 surfaces are also capable of inactivating different types of single-stranded RNA (ssRNA) viruses independent of whether their structure presents an envelop or not. The antiviral property of Si 3 N 4 derives from a hydrolysis reaction at its surface and the subsequent formation of reactive nitrogen species (RNS) in doses that could be metabolized by mammalian cells but are lethal to pathogens. Real-time reverse transcription (RT)-polymerase chain reaction (PCR) tests of viral RNA and in situ Raman spectroscopy suggested that the products of Si 3 N 4 hydrolysis directly react with viral proteins and RNA. Si 3 N 4 may have a role in controlling human epidemics related to ssRNA mutant viruses.

This study targets on-site/real-time taxonomic identification and metabolic profiling of seven different Candida auris clades/subclades by means of Raman spectroscopy and imaging. Representative Raman spectra from different Candida auris samples were systematically deconvoluted by means of a customized machine-learning algorithm linked to a Raman database in order to decode structural differences at the molecular scale. Raman analyses of metabolites revealed clear differences in cell walls and membrane structure among clades/subclades. Such differences are key in maintaining the integrity and physical strength of the cell walls in the dynamic response to external stress and drugs. It was found that Candida cells use the glucan structure of the extracellular matrix, the degree of α-chitin crystallinity, and the concentration of hydrogen bonds between its antiparallel chains to tailor cell walls’ flexibility. Besides being an effective ploy in survivorship by providing stiff shields in the α–1,3–glucan polymorph, the α–1,3–glycosidic linkages are also water-insoluble, thus forming a rigid and hydrophobic scaffold surrounded by a matrix of pliable and hydrated β–glucans. Raman analysis revealed a variety of strategies by different clades to balance stiffness, hydrophobicity, and impermeability in their cell walls. The selected strategies lead to differences in resistance toward specific environmental stresses of cationic/osmotic, oxidative, and nitrosative origins. A statistical validation based on principal component analysis was found only partially capable of distinguishing among Raman spectra of clades and subclades. Raman barcoding based on an algorithm converting spectrally deconvoluted Raman sub-bands into barcodes allowed for circumventing any speciation deficiency. Empowered by barcoding bioinformatics, Raman analyses, which are fast and require no sample preparation, allow on-site speciation and real-time selection of appropriate treatments.