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In this work, the fatigue and cellular performance of novel superficially treated porous titanium dental implants made up using conventional powder metallurgy and space-holder techniques (30 vol.% and 50 vol.%, both with a spacer size range of 100–200 µm) are evaluated. Before the sintering stage, a specific stage of CNC milling of the screw thread of the implant is used. After the consolidation processing, different surface modifications are performed: chemical etching and bioactive coatings (BG 45S5 and BG 1393). The results are discussed in terms of the effect of the porosity, as well as the surface roughness, chemical composition, and adherence of the coatings on the fatigue resistance and the osteoblast cells' behavior for the proposed implants. Macro-pores are preferential sites of the nucleation of cracks and bone cell adhesion, and they increase the cellular activity of the implants, but decrease the fatigue life. In conclusion, SH 30 vol.% dental implant chemical etching presents the best bio-functional (in vitro osseointegration) and bio-mechanical (stiffness, yield strength and fatigue life) balance, which could ensure the required characteristics of cortical bone tissue. [ABSTRACT FROM AUTHOR]

Despite the increasing progress achieved in the last 20 years in both the fabrication of porous dental implants and the development of new biopolymers for targeting drug therapy, there are important issues such as bone resorption, poor osseointegration, and bacterial infections that remain as critical challenges to avoid clinical failure problems. In this work, we present a novel microtechnology based on polycaprolactone microspheres that can adhere to porous titanium implant models obtained by the spacer holder technique to allow a custom biomechanical and biofunctional balance. For this purpose, a double emulsion solvent evaporation technique was successfully employed for the fabrication of the microparticles properly loaded with the antibacterial therapeutic agent, rose bengal. The resulting microspheres were infiltrated into porous titanium substrate and sintered at 60 °C for 1 h, obtaining a convenient prophylactic network. In fact, the sintered polymeric microparticles were demonstrated to be key to controlling the drug dissolution rate and favoring the early healing process as consequence of a better wettability of the porous titanium substrate to promote calcium phosphate nucleation. Thus, this joint technology proposes a suitable prophylactic tool to prevent both early-stage infection and late-stage osseointegration problems. [ABSTRACT FROM AUTHOR]

Here, titanium porous substrates were fabricated by a space holder technique. The relationship between microstructural characteristics (pore equivalent diameter, mean free-path between pores, roughness and contact surface), mechanical properties (Young's modulus, yield strength and dynamic micro-hardness) and bacterial behavior are discussed. The bacterial strains evaluated are often found on dental implants: Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. The colony-forming units increased with the size of the spacer for both types of studied strains. An antibiofouling synthetic coating based on a sulfonated polyetheretherketone polymer revealed an effective chemical surface modification for inhibiting MRSA adhesion and growth. These findings collectively suggest that porous titanium implants designed with a pore size of 100–200 µm can be considered most suitable, assuring the best biomechanical and bifunctional anti-bacterial properties. [ABSTRACT FROM AUTHOR]

Tooth loss is common in patients struggling with dental cavities, periodontal diseases, and tumors, as well as those who abuse tobacco or drugs. In this scenario, dental implants have become the primary treatment option for complete or partial tooth loss. Dental implant failure can be caused by stress shielding phenomenon, poor osseointegration, or to bacterial infections. In the present study, a joint solution to these limitations is proposed using a variety of porous β-titanium substrates using powder Ti35Nb7Zr5Ta alloy and employing the spacer-holder approach (ammonium bicarbonate) to obtain a variety of porosity percentage (30, 40, and 50 vol%), and pore diameters in 100–200 μm, that has been characterized in terms of its size distribution, density, morphology, chemical composition, compaction ability and Vickers micro-hardness. Furthermore, porosity, microstructure (Archimedes and image analysis) and tribomechanical behavior (P-h curves and scratch tests) experiments were performed to study and characterize the porous substrates. Polyvinyl alcohol (PVA)/poly-ε-caprolactone (PCL) containing silver nanoparticles (AgNPs), as antibacterial composite, was employed to infiltrate β-Ti disks. Scanning electron microscopy was used to determine the coating morphology, thickness, and infiltration of the porous substrates. Wettability and SBF experiments were also carried out to investigate hydrophobicity and potential bio-functionality. The results suggested how the porosity of the β-Ti alloy affects the mechanical characteristics and the wettability of the substrate that was successfully infiltrated to exert an antimicrobial behavior. [Display omitted] • Novel beta porous titanium implant coated with therapeutic biocomposite. • Bio-functional antibacterial behavior of PVA/PCL/AgNPs biocomposite. • A solution to improve the tribomechanical and biofunctional behavior of metal implants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design and simulation by FEM of customized scaffolds fixed to the jaw by a dental implant. • Distribution of stress in crown, dental implant, scaffold, cortical and trabecular bone, and strain in the cortical and trabecular bone. • Influence of the porosity and hole size of the scaffolds on the stress and strain in the cortical and trabecular bone. • The use of customized scaffolds allows a significant reduction in stresses and strain in the peri-implant cortical bone. Teeth loss due to periodontal diseases, trauma, or infections often causes dimensional loss in the affected maxillary. In patients with reduced maxillary size, restoration of chewing function and esthetics with endosseous dental implants may fail. The aim of this work was to simulate the biomechanical behavior, using the finite element method, of customized scaffolds fixed by a dental implant on a partially edentulous jaw. Porous scaffolds were designed from medical images of a partially edentulous jaw with type IV bone quality. The influence of the diameter of the hole and the porosity of the scaffold on the maximum levels of stress and strain in the peri -implant bone was evaluated. The highest stress values in the scaffolds, dental implant, and crown were lower than the yield strength of their respective materials. The customized scaffolds allow to recover the dimensions of the evaluated jaw. A significant decrease in stress and strain values was observed in the peri -implant cortical bone. Furthermore, it was found that the evaluated parameters did not have a significant influence on the maximum von Mises equivalent stress and maximum strain values in the peri -implant bone. [ABSTRACT FROM AUTHOR]

Stress-shielding and loosening compromise the success of dental implants under real-life service conditions. This work evaluates the mechanical behavior of superficially modified porous titanium dental implants fabricated by two different routes: conventional powder-metallurgy and space-holder techniques. A novel, feasible and repetitive protocol of micro-milling of the implant thread (before sintering), as well as surface modification treatments (after sintering) are also implemented. The discussion is conducted in terms of the influence of porosity and surface roughness on the stiffness and yield strength of implants. The macro-pores concentrate stress locally, and, at the same time, they could act as a barrier to the propagation of micro-cracks. Higher rugosity was observed for virgin implants obtained with spacer particles. Concerning superficially modified implants, while bioglass 1393 was the most effective coating due to its greater infiltration and adhesion capacity, chemical etching could improve osteoblast adhesion because modifies the roughness of the implant surface. • Novel protocol for micro-milling the implant threads • Influence of porosity on mechanical behavior of dental implants • Pores as sites for nucleation and barrier to propagation of micro-cracks • Chemical etching and bioactive coating to improve osseointegration • BG1393 presents better infiltration and adhesion capacity in pores [ABSTRACT FROM AUTHOR]