Pore throat size and connectivity determine bone and tissue ingrowth into porous implants : three-dimensional micro-CT based structural analyses of porous bioactive titanium implants

Purpose The purpose of the present study was to evaluate the distribution of stresses and consequent bone volume affected surrounding external hexagon or Morse taper dental implant systems by finite element analysis. Material and methods Two different dental implant-abutment designs were assessed: external hexagon or Morse taper joints. A mandibular bone model obtained from a computed tomography scan was used. The implant-abutment systems were axially or obliquely (45°) loaded on 150  N relatively to the central axis of the implant. The von Mises stresses were analysed in terms of magnitude and volume of affected surrounding bone. Results The von Mises equivalent values found on the cortical bone were higher than that recorded on the trabecular bone. Additionally, the bone volume associated with high stress values was higher in cortical and trabecular bone for oblique loading compared to axial loading. The values of von Mises equivalent stress around Morse taper implant-abutment system were lower on both axial and oblique loads than those recorded for external hexagon implant-abutment systems. Conclusions Morse taper implant joints revealed a proper biomechanical behavior when compared to external hexagon systems concerning a significant volume of surrounding peri-implant bone subjected to lower stresses values.

https://repositorium.sdum.uminho.pt/bitstream/1822/53334/1/art20.pdf

Finite element analysis of stress extent at peri-implant bone surrounding external hexagon or Morse taper implants

Independent tuning of stiffness and toughness of additively manufactured titanium-polymer composites: Simulation, fabrication, and experimental studies

Ti6Al4V porous scaffolds of two unit cell geometries (reentrant and cubic) were investigated as candidates for load-bearing biomedical applications. Samples were fabricated using an Arcam A2 electron beam melting (EBM) machine and evaluated for geometric deviation from the original CAD design using a digital optical microscope. The mass and bounding volume of each sample were also measured to calculate the resulting relative density. The scaffolds were loaded in compression in the build direction to determine the relative modulus of elasticity and ultimate compressive load. Experimental results were used to calculate the Gibson and Ashby relation parameters for the studied unit cell geometries. The results suggest that samples with the cubic unit cell geometries, with struts oriented at an angle of 45° to the loading direction, exhibited higher stiffness than samples with the reentrant unit cell geometry at equivalent relative densities. A cubic scaffold is verified to withstand high compressive loads (more than 71 kN) while having an approximate pore size in the range of 0.6 mm. These characteristics demonstrate its suitability for load bearing biomedical implants.

Electron beam melted scaffolds for orthopedic applications

In recent years, significant progress has been made toward the development of titanium foams, or porous titanium scaffolds, for orthopedic and dental applications. This chapter provides an overview of the possibilities, limitations, and challenges involved in using titanium foam scaffolds for dental applications. It outlines the underlying research that led to the development of commonly used titanium and titanium alloys for dental implants. The chapter further aims to highlight some of the fundamental parameters of porous dental implants that allow for enhanced osseointegration, stability, and effective dental rehabilitation, including dimensional considerations and alloy selection, mechanical properties, and pore characteristics. Furthermore, an attempt has also been made to categorize titanium dental implants according to their type and design, including implants with fully porous structures, implants with porous surfaces and a solid core, and implants with a thin porous surface.

Titanium foam scaffolds for dental applications

https://www.intechopen.com/citation-pdf-url/39773

Finite element analysis of stress at implant–bone interface of dental implants with different structures

Titanium and titanium alloy implants are essential for bone tissue regeneration engineering. The current trend is toward the manufacture of implants from materials that mimic the structure, composition and elasticity of bones. Titanium and titanium alloy implants, the most common materials for implants, can be used as a bone conduction material but cannot promote osteogenesis. In clinical practice, there is a high demand for implant surfaces that stimulate bone formation and accelerate bone binding, thus shortening the implantation-to-loading time and enhancing implantation success. To avoid stress shielding, the elastic modulus of porous titanium and titanium alloy implants must match that of bone. Micro-arc oxidation technology has been utilized to increase the surface activity and build a somewhat hard coating on porous titanium and titanium alloy implants. More recently, a growing number of researchers have combined micro-arc oxidation with hydrothermal, ultrasonic, and laser treatments, coatings that inhibit bacterial growth, and acid etching with sand blasting methods to improve bonding to bone. This paper summarizes the reaction at the interface between bone and implant material, the porous design principle of scaffold material, MAO technology and the combination of MAO with other technologies in the field of porous titanium and titanium alloys to encourage their application in the development of medical implants.

/pdf/porous-construction-and-surface-modification-of-titanium-t6pflh4u.pdf

Rui-fang Wang

Papers

Finite element analysis of stress at implant–bone interface of dental implants with different structures

Porous construction and surface modification of titanium-based materials for osteogenesis: A review