Histomorphometric assessments of peri-implant bone around Ti-Nb-Sn alloy implants with low Young's modulus

Green Synthesis and Biosafety Assessment of MXene

The rise of MXene-based materials with fascinating physical and chemical properties has attracted wide attention in the field of biomedicine, because it can be exploited to regulate a variety of biological processes. The biomedical applications of MXene are still in its infancy, nevertheless, the comprehensive evaluation of MXene's biosafety is desperately needed. In this review, the composition and the synthetic methods of MXene materials are first introduced from the view of biosafety. The evaluation of the interaction between MXene and cells, as well as the safety of different forms of MXene applied in vivo are then discussed. This review provides a basic understanding of MXene biosafety and may bring new inspirations to the future applications of MXene-based materials in biomedicine.

Low Young's Modulus TiNbSn Alloy Locking Plates Accelerate Osteosynthesis in Rabbit Tibiae

A new beta TiNbSn alloy with a low Young's modulus of approximately 40 GPa has been developed to resolve the stress shielding by Young's modulus divergence. In this study, the efficacy of TiNbSn alloy locking plates on bone repair is compared to that of commercially pure titanium (CP-Ti). The TiNbSn alloy and CP-Ti, which have Young's moduli of 49.1 GPa and 107 GPa, respectively, were compared. Male Japanese white rabbits were anesthetized, and osteotomy and osteosynthesis with locking plates were performed on the right tibia. The bone repair was assessed using micro-computed tomography (CT), histomorphometry, immunohistochemistry, and mechanical testing. Micro-CT, histomorphometry, immunohistochemistry, and mechanical testing were performed four weeks after osteotomy. Six weeks after surgery, micro-CT and mechanical testing were performed. Micro-CT analysis at four weeks after surgery showed that the intramedullary fracture callus in the TiNbSn alloy group had more bone volume and numerous bridging structures compared to the CP-Ti group (CP-Ti vs. TiNbSn alloy, 34.3 ± 13.1 mm3 vs. 61.3 ± 19.6 mm3, p = 0.02; mean ± standard deviation). At four weeks post-osteotomy, the healed tibia showed significantly higher strength in the TiNbSn alloy group compared with CP-Ti (CP-Ti vs. TiNbSn alloy, 81.3 ± 31.2 N vs. 133.7 ± 46.6 N, p = 0.04). TiNbSn alloy locking plates had a more positive impact on bone formation and bone strength restoration than the CP-Ti locking plates during the early phase of bone healing.

Differences in the effect of surface texturing on the wear loss of β-type Ti-Nb-Ta-Zr and (α+β)-type Ti-6Al-4V ELI alloys in contact with zirconia in physiological saline solution

The effectiveness of dimple surface texturing via picosecond pulsed laser processing for reducing wear loss was investigated using two types of titanium alloys, β-type Ti-29Nb-13Ta-4.6Zr (TNTZ) and α+β-type Ti-6Al-4V ELI (Ti64). The two alloys showed different modes of wear against zirconia. As the sliding distance increased, the wear loss was observed to increase for Ti64, but not necessarily for TNTZ. The wear debris of Ti64 acted as abrasive particles, but that of TNTZ easily adhered to the surface, and the adhered wear debris turned into a hard wear-protective layer. Therefore, the dependence of wear loss on the sliding distance for these two titanium alloys could be attributed to the difference in the roles of wear debris between each titanium alloy and zirconia. Further, depending on this difference in wear mode, the effect of dimple surface texturing on the wear was found to be different in Ti64 and TNTZ. As the dimples can trap the wear debris, they are effective for reducing wear in Ti64 but are detrimental in TNTZ.

New Zr-Ti-Nb Alloy for Medical Application: Development, Chemical and Mechanical Properties, and Biocompatibility

The concept of mechanical biocompatibilities is considered an important factor for orthopedics and dental implants. The high Young modulus of traditional Ti-based alloys can lead to stress-shielding syndrome and late postoperative complications. The development of new Al- and V-free Ti alloys with a low elastic modulus is a critical task for implantology. Despite the relatively low Young modulus and appropriate biological response of metastable beta-Ti alloys, their production requires complex metallurgical solutions and a high final cost that limit commercial application. The current research aimed to develop a Zr-Ti-Nb system with a low Young modulus suitable for biomedical application, including orthopedics and dental implantology. Two different charges were used for new alloy production with melting in a vacuum-arc furnace VDP-1 under atmospheric control (argon + helium) with a non-consumable tungsten electrode and a water-cooled copper crystallizer. Post-treatment included a forging-rolling process to produce a bar suitable for implant production. SEM with EDX and the mechanical parameters of the new alloy were evaluated, and a cell culture experiment provided a biocompatibility assessment. The chemical composition of the new alloy can be represented as 59.57-19.02-21.41 mass% of Zr-Ti-Nb. The mechanical properties are characterized by an extremely low Young modulus—27,27 GPa for the alloy and 34.85 GPa for the bar. The different master alloys used for Zr-Ti-Nb production did not affect the chemical compound and mechanical parameters so it was possible to use affordable raw materials to decrease the final price of the new product. The cell culture experiment demonstrated a full biocompatibility, indicating that this new alloy can be used for dental and orthopedics implant production.