Nanostructured commercially pure titanium (CP Ti) has become technologically and commercially interesting because of its enhanced mechanical and functional properties. The superior strength of nanostructured CP Ti provides an opportunity to reduce the size of biomedical implants so miniaturized implants can bear the same mechanical load as their conventional counterparts. Improved biocompatibility and bioactivity of nanostructured CP Ti allow the minimization of the postsurgery rehabilitation period of patients. This chapter gives an overview on the application of nanostructured CP Ti in two types of implants: small-diameter dental implants and maxillofacial mini-implants. For these medical applications, >9000 nanostructured items have been placed with no reported cases of failure. Attention is also paid to the commercially viable processing routes for manufacturing of nanostructured CP Ti, its superior mechanical properties and functional performance, and the future prospective uses of this unique material in biomedical engineering.

The study is aimed to virtually miniaturize medical implants produced of the biocompatible Ti with improved mechanical performance. The results on the simulation-driven design of medical implants fabricated of nanostructured commercially pure Ti with significantly enhanced mechanical properties are presented. The microstructure of initially coarse-grained Ti has been refined to ultrafine grain size by severe plastic deformation. The ultrafine-grained (UFG) Ti exhibits remarkably high static and cyclic strength, allowing to design new dental and surgical implants with miniaturized geometry. The possibilities to reduce the implant dimensions via virtual fatigue tests for the digital twins of two particular medical devices (a dental implant and a maxillofacial surgery plate) are explored with the help of finite element modeling. Additionally, the effect of variation in loading direction and the fixation methods for the tested implants are studied in order to investigate the sensitivity of the fatigue test results to the testing conditions. It is shown that the UFG materials are promising for the design of a new generation of medical products.

This paper evaluates the fatigue strength of ultrafine-grained (UFG) Grade 4 Ti in the low-cycle fatigue region, as well as the strength of medical implants (plates and screws) made of UFG Ti under various types of loading in comparison with the strength of products made of coarse-grained (CG) Ti. To produce a UFG state, titanium billets after annealing were processed by the ECAP-Conform technique. The fatigue of the prismatic specimens with a thickness of 10 mm from CG and UFG Ti was tested by the three-point bending method using an Instron 8802 facility. The modeling and evaluation of the stress-strain state in the ANSYS software package for finite-element analysis revealed, in particular, the localization of equivalent stresses in the area of hole edges and at fillets during the tension of the plates. The performed research has demonstrated that medical implants (plates and screws) from UFG Grade 4 Ti have a higher strength under different types of loading (tension, fatigue strength, torsion) in comparison with products from CG Ti. This opens up a possibility for the miniaturization of medical products from UFG Ti while preserving their main performance properties at an acceptable level.

This paper presents the results of comprehensive in vivo studies into the osseointegration behavior of medical implants for maxillofacial surgery produced from nanostructured grade 4 titanium. Special attention is given to the phenomenology of bone tissue formation with consideration of its surface relief features and to evaluating the quantitative parameters of the morphological indicators of osteoblast and endothelial cells in the osseointegration zone. These parameters were compared with their measurement data for standard factory-made implants, and considerable acceleration in the fixation of nanotitanium implants due to osseointegation was found. The obtained results indicate a better osseointegration of implants made of nanotitanium in comparison to similar standard products.

This paper discusses the formation of ultrafine-grained (UFG) structure and nanosized second-phase precipitates in commercially pure Grade 4 titanium subjected to severe plastic deformation by high pressure torsion at room temperature with subsequent heat treatment. It was found that the combined processing of Grade 4 titanium provides very high tensile strength (σ_u ≈ 1500 MPa), which significantly exceeds the previous results for this material. Analysis of the strengthening mechanisms showed that the superstrength of commercially pure titanium is due to several factors: UFG structure formation, dispersion strengthening from second-phase nanoparticles, high dislocation density, and grain boundary segregation. The contribution of these strengthening mechanisms is evaluated and compared with experimental data.

Titanium and its alloys are popular materials for medical application, particularly in implant devices, where high mechanical properties and osseointegration are critical factors for successful implantation. In this work, the progress in the studies of nanostructured commercially pure Grade 4 titanium (nanoTi) is demonstrated, in which an ultrafine-grained structure with nanoscale grain size is formed using severe plastic deformation processing. Nanostructured Grade 4 Ti has a very high strength, and its physical nature and strengthening mechanisms are analyzed herein. NanoTi proved also to have very high osseointegration during in vivo experiments. At the same time, the highest biofunctionality is demonstrated by the etched nanoTi samples with pronounced surface roughness, the latter being revealed from precise roughness measurements. The present study provided convincing evidence of accelerated bone formation on nanoTi, which is very promising for manufacture of dental and maxillofacial implants.