A Critical Review of Additive Manufacturing Techniques and Associated Biomaterials Used in Bone Tissue Engineering

Abstract

With the ability to fabricate complex structures while meeting individual needs, additive manufacturing (AM) offers unprecedented opportunities for bone tissue engineering in the biomedical field. However, traditional metal implants have many adverse effects due to their poor integration with host tissues, and therefore new material implants with porous structures are gradually being developed that are suitable for clinical medical applications. From the perspectives of additive manufacturing technology and materials, this article discusses a suitable manufacturing process for ideal materials for biological bone tissue engineering. It begins with a review of the methods and applicable materials in existing additive manufacturing technologies and their applications in biomedicine, introducing the advantages and disadvantages of various AM technologies. The properties of materials including metals and polymers, commonly used AM technologies, recent developments, and their applications in bone tissue engineering are discussed in detail and summarized. In addition, the main challenges for different metallic and polymer materials, such as biodegradability, anisotropy, growth factors to promote the osteogenic capacity, and enhancement of mechanical properties are also introduced. Finally, the development prospects for AM technologies and biomaterials in bone tissue engineering are considered.

Regeneration of Critical‐Sized Mandibular Defects Using 3D‐Printed Composite Scaffolds: A Quantitative Evaluation of New Bone Formation in In Vivo Studies

“…[ 45 ] Despite the high resolutions that can be reached with vat photopolymerization techniques, there are some challenges that limit their translation into clinical application, such as the limited availability of biocompatible resins and photo‐initiators, degradation time of the scaffolds and high costs. [ 66,67 ]…”

“…In BTE, a wide variety of techniques are employed, and they can be categorized in seven classes: material jetting, binder jetting, vat photopolymerization (e.g., DLP, SLA), powder bed fusion [e.g., SLS, selective laser melting (SLM)], material extrusion [e.g., FDM, liquid deposition modeling (LDM), robocasting], and electrospinning. [66,67] However, for mandibular applications, only SLS, inkjet printing, FDM, LDM, robocasting, and DLP have mostly been employed (Table 4). LDM, FDM and robocasting are the most used techniques.…”

“…However, they are usually associated with limited resolution (≈300 μm), and the final parts can exhibit anisotropic behavior. [22,67,68] FDM is based on the extrusion of melted materials; those that are mainly used for mandible reconstruction are composites formed by a polymeric (i.e., PCL, PLA, PLGA) and a ceramic part (i.e., TCP, HA). Since the melting process usually implies high temperatures, biological organic components (e.g., growth factors) need to be eventually incorporated at a later time.…”

“…[45] Despite the high resolutions that can be reached with vat photopolymerization techniques, there are some challenges that limit their translation into clinical application, such as the limited availability of biocompatible resins and photo-initiators, degradation time of the scaffolds and high costs. [66,67] Two other less commonly used AM techniques are SLS and inkjet printing. SLS belongs to the powder bed fusion category, and relies on a laser energy source to locally sinter the material, usually in the form of powder (Figure 3C).…”

“…[23] Although scaffolds generated with this technique require post-processing op-erations, SLS allows large and very complex structures to be produced at good resolution (≈500 μm). [23,[66][67][68] An example is reported in the work of Roskies et al A 3D scaffold of PEEK was manufactured with a CO 2 laser source, obtaining a total porosity around 50% and a pore size of 730 μm. [49] Lastly, Konopniki et al have used inkjet printing to fabricate PCL/𝛽-TCP scaffolds.…”