Exploring Macroporosity of Additively Manufactured Titanium Metamaterials for Bone Regeneration with Quality by Design: A Systematic Literature Review

Abstract

Additive manufacturing facilitates the design of porous metal implants with detailed internal architecture. A rationally designed porous structure can provide to biocompatible titanium alloys biomimetic mechanical and biological properties for bone regeneration. However, increased porosity results in decreased material strength. The porosity and pore sizes that are ideal for porous implants are still controversial in the literature, complicating the justification of a design decision. Recently, metallic porous biomaterials have been proposed for load-bearing applications beyond surface coatings. This recent science lacks standards, but the Quality by Design (QbD) system can assist the design process in a systematic way. This study used the QbD system to explore the Quality Target Product Profile and Ideal Quality Attributes of additively manufactured titanium porous scaffolds for bone regeneration with a biomimetic approach. For this purpose, a total of 807 experimental results extracted from 50 different studies were benchmarked against proposed target values based on bone properties, governmental regulations, and scientific research relevant to bone implants. The scaffold properties such as unit cell geometry, pore size, porosity, compressive strength, and fatigue strength were studied. The results of this study may help future research to effectively direct the design process under the QbD system.

Synthesis and Characterization of a Novel Biocompatible Alloy, Ti-Nb-Zr-Ta-Sn

“…Though much progress has been made in the development of biomedical implants, about 20% of patients still suffer from severe problems caused by design, manufacturing, and material selection issues [ 42 ]. One material selection issue results in stress shielding, this being the large difference in elastic modulus between the implant alloy (in most cases, the Ti-6Al-4V alloy because of its biocompatibility and low density) and that of the surrounding bone, resulting in bone resorption and, eventually, loosening of the implant [ 37 , 42 , 43 , 44 ]. Thus, there is much research interest in the development of low elastic modulus Ti-based alloys [ 15 , 42 ].…”

“…One material selection issue results in stress shielding, this being the large difference in elastic modulus between the implant alloy (in most cases, the Ti-6Al-4V alloy because of its biocompatibility and low density) and that of the surrounding bone, resulting in bone resorption and, eventually, loosening of the implant [ 37 , 42 , 43 , 44 ]. Thus, there is much research interest in the development of low elastic modulus Ti-based alloys [ 15 , 42 ]. Low elastic modulus can be achieved by modification of the composition of the alloy through the addition of certain elements.…”

Titanium Functionalized with Polylysine Homopolymers: In Vitro Enhancement of Cells Growth

“…Dental implants are multi-material prostheses that replace tooth roots with screwlike metal fixtures surgically inserted into the edentulous bone that are connected by the Dental implants are multi-material prostheses that replace tooth roots with screw-like metal fixtures surgically inserted into the edentulous bone that are connected by the abutment with an artificial crown that replaces the missing tooth, looking and acting identical to the real one (Figure 1). Dental implants fixtures are generally composed of biomedical titanium and its alloys [1], as they are biocompatible as well as resistant to corrosion and strength [2].…”

“…A model of study on the osteogenic effects of substances is the use of human dental pulp stem cells [22][23][24], which previously has been proven to be involved in bone-implant osseointegration [25][26][27][28]. In details, the role of induced pluripotent stem cells in dentistry has been recently discussed and the use of autologous dental-derived stem cells has been proposed Dental implants fixtures are generally composed of biomedical titanium and its alloys [1], as they are biocompatible as well as resistant to corrosion and strength [2].…”

A Micro-Computed Tomography Comparison of the Porosity in Additively Fabricated CuCr1 Alloy Parts Using Virgin and Surface-Modified Powders

“…Porosity is an important subject in the additive manufacturing (AM) research field. Desired or engineered porosity is utilized nowadays for the production of bio-compatible metal implants and prostheses [1,2], bio-active ceramic scaffolds [3,4], geopolymer filters for water treatments [5], breathable steel for molding components [6], and multiple other applications [7]. The intrinsic design freedom of the additive process grants that the porosity can be engineered to a level of detail that is governed by the accuracy and precision of the process itself [8].…”