Craniofacial Applications Research Articles

In vitro calibration and in vivo validation of phenomenological corrosion models for resorbable magnesium-based orthopaedic implants

Metallic bioresorbable orthopaedic implants based on magnesium, iron and zinc-based alloys that provide rigid internal fixation without foreign-body complications associated with permanent implants have great potential as next-generation orthopaedic devices. Magnesium (Mg) based alloys exhibit excellent biocompatibility. However, the mechanical performance of such implants for orthopaedic applications is contingent on limiting the rate of corrosion in vivo throughout the bone healing process. Additionally, the surgical procedure for the implantation of internal bone fixation devices may impart plastic deformation to the device, potentially altering the corrosion rate of the device. The primary objective of this study was to develop a computer-based model for predicting the in vivo corrosion behaviour of implants manufactured from a Mg-1Zn-0.25Ca ternary alloy (ZX10). The proposed corrosion model was calibrated with an extensive range of mechanical and in vitro corrosion testing. Finally, the model was validated by comparing the in vivo corrosion performance of the implants during preliminary animal testing with the corrosion performance predicted by the model. The proposed model accurately predicts the in vitro corrosion rate, while overestimating the in vivo corrosion rate of ZX10 implants. Overall, the model provides a “first-line of design” for the development of new bioresorbable Mg-based orthopaedic devices. Statement of significanceBiodegradable metallic orthopaedic implant devices have emerged as a potential alternative to permanent implants, although successful adoption is contingent on achieving an acceptable degradation profile. A reliable computational method for accurately estimating the rate of biodegradation in vivo would greatly accelerate the development of resorbable orthopaedic implants by highlighting the potential risk of premature implant failure at an early stage of the device development. Phenomenological corrosion modelling approach is a promising computational tool for predicting the biodegradation of implants. However, the validity of the models for predicting the in vivo biodegradation of Mg alloys is yet to be determined. Present study investigates the validity of the phenomenological modelling approach for simulating the biodegradation of resorbable metallic orthopaedic implants by using a porcine model that targets craniofacial applications.

Injectable periodontal ligament stem cell-metformin-calcium phosphate scaffold for bone regeneration and vascularization in rats.

Injectable and self-setting calcium phosphate cement scaffold (CPC) capable of encapsulating and delivering stem cells and bioactive agents would be highly beneficial for dental and craniofacial repairs. The objectives of this study were to: (1) develop a novel injectable CPC scaffold encapsulating human periodontal ligament stem cells (hPDLSCs) and metformin (Met) for bone engineering; (2) test bone regeneration efficacy in vitro and in vivo. hPDLSCs were encapsulated in degradable alginate fibers, which were then mixed into CPC paste. Five groups were tested: (1) CPC control; (2) CPC +hPDLSC-fibers +0% Met (CPC + hPDLSCs + 0%Met); (3) CPC +hPDLSC-fibers +0.1% Met (CPC + hPDLSCs + 0.1%Met); (4) CPC +hPDLSC-fibers +0.2% Met (CPC + hPDLSCs + 0.2%Met); (5) CPC +hPDLSC-fibers +0.4% Met (CPC + hPDLSCs + 0.4%Met). The injectability, mechanical properties, metformin release, and hPDLSC osteogenic differentiation and bone mineral were determined in vitro. A rat cranial defect model was used to evaluate new bone formation. The novel construct had good injectability and physical properties. Alginate fibers degraded in 7 days and released hPDLSCs, with 5-fold increase of proliferation (p＜0.05). The ALP activity and mineral synthesis of hPDLSCs were increased by Met delivery (p＜0.05). Among all groups, CPC+hPDLSCs+0.1%Met showed the greatest cell mineralization and osteogenesis, which were 1.5-10folds those without Met (p＜0.05). Compared to CPC control, CPC+hPDLSCs+0.1%Met enhanced bone regeneration in rats by 9 folds, and increased vascularization by 3 folds (p＜0.05). The novel injectable construct with hPDLSC and Met encapsulation demonstrated excellent efficacy for bone regeneration and vascularization in vivo in an animal model. CPC+hPDLSCs+0.1%Met is highly promising for dental and craniofacial applications.

3D printing for bone regeneration: challenges and opportunities for achieving predictability.

3D printing offers attractive opportunities for large-volume bone regeneration in the oro-dental and craniofacial regions. This is enabled by the development of CAD-CAM technologies that support the design and manufacturing of anatomically accurate meshes and scaffolds. This review describes the main 3D-printing technologies utilized for the fabrication of these patient-matched devices, and reports on their pre-clinical and clinical performance including the occurrence of complications for vertical bone augmentation and craniofacial applications. Furthermore, the regulatory pathway for approval of these devices is discussed, highlighting the main hurdles and obstacles. Finally, the review elaborates on a variety of strategies for increasing bone regeneration capacity and explores the future of 4D bioprinting and biodegradable metal 3D printing.

Calvaria defect regeneration via human periodontal ligament stem cells and prevascularized scaffolds in athymic rats

BackgroundVascularization plays an important role in dental and craniofacial regenerations. Human periodontal ligament stem cells (hPDLSCs) are a promising cell source and, when co-cultured with human umbilical vein endothelial cells (hUVECs), could promote vascularization. The objectives of this study were to develop a novel prevascularized hPDLSC-hUVEC-calcium phosphate construct, and investigate the osteogenic and angiogenic efficacy of this construct with human platelet lysate (hPL) in cranial defects in rats for the first time. MethodshPDLSCs and hUVECs were co-cultured on calcium phosphate cement (CPC) scaffolds with hPL. Cell proliferation, angiogenic gene expression, angiogenesis, alkaline phosphatase activity, and cell-synthesized minerals were determined. Bone and vascular regenerations were investigated in rat critical-sized cranial defects in vivo. ResultshPDLSC-hUVEC-CPC-hPL group had 2-fold greater angiogenic expressions and cell-synthesized mineral synthesis than hPDLSC-hUVEC-CPC group (p < 0.05). Microcapillary-like structures were formed on scaffolds in vitro. hPDLSC-hUVEC-CPC-hPL group had more vessels than hPDLSC-hUVEC-CPC group (p < 0.05). In cranial defects in rats, hPDLSC-hUVEC-CPC-hPL group regenerated new bone amount that was 2.1 folds and 4.0 folds, respectively, that of hPDLSC-hUVEC-CPC group and CPC control (p < 0.05). New blood vessel density of hPDLSC-hUVEC-CPC-hPL group was 2 folds and 7.9 folds, respectively, that of hPDLSC-hUVEC-CPC group and CPC control (p < 0.05). ConclusionThe hPL pre-culture method is promising to enhance bone regeneration via prevascularized CPC. Novel hPDLSC-hUVEC-CPC-hPL prevascularized construct increased new bone formation and blood vessel density by 4–8 folds over CPC control. Clinical significanceNovel hPDLSC-hUVEC-hPL-CPC prevascularized construct greatly increased bone and vascular regeneration in vivo and hence is promising for a wide range of craniofacial applications.

Scaffolds for Use in Craniofacial Bone Regeneration.

Tissue-engineered scaffolds have been identified as appropriate templates for bone regeneration, especially complex geometries seen in craniofacial defects. Here we describe the general fabrication and modification of hydrogels, cryogels, and electrospun scaffolds. These scaffolds offer a variety of templates for facilitating bone growth and regeneration in craniofacial applications.

A comparative study on silicon nitride, titanium and polyether ether ketone on mouse pre-osteoblast cells.

The current study provides more insights about the surface bioactivity of the silicon nitride (Si3N4) as a potential candidate for bone regeneration in craniofacial and orthopaedic applications compared with conventional implantation materials. Current skeletal reconstructive materials such as titanium and polyether ether ketone (PEEK) are limited by poor long-term stability, biocompatibility and prolonged healing. Si3N4 is an FDA-approved material for an intervertebral spacer in spinal fusion applications. It is biocompatible and has antimicrobial properties. Here, we hypothesize that Si3N4 was found to be an osteoconductive material and conducts the growth, differentiation of MC3T3-E1 cells for extracellular matrix deposition, mineralization and eventual bone regeneration for craniofacial and orthopaedic applications. MC3T3-E1 cells were used to study the osteoblastic differentiation and mineralization on sterile samples of Si3N4, titanium alloy and PEEK. The samples were then analysed for extracellular matrix deposition and mineralization by FTIR, Raman spectroscopy, SEM, EDX, Alizarin Red, qRT-PCR and ELISA. The in vitro study indicates the formation of collagen fibres and mineral deposition on all three sample surfaces. There was more profound and faster ECM deposition and mineralization on Si3N4 surface as compared to titanium and PEEK. The FTIR and Raman spectroscopy show formation of collagen and mineral deposition at 30 days for Si3N4 and titanium and not PEEK. The peaks shown by Raman for Si3N4 resemble closely to natural bone. Results also indicate the upregulation of osteogenic transcription factors such as RUNX2, SP7, collagen type I and osteocalcin. The authors concluded that Si3N4 rapidly conducts mineralized tissue formation via extracellular matrix deposition and biomarker expression in mouse calvarial pre-osteoblast cells. Thus, this study confirms that the bioactive Si3N4 could be a potential material for craniofacial and orthopaedic applications leading to rapid bone regeneration that resemble the natural bone structure.

Three-Dimensional Stereophotogrammetry in the Evaluation of Craniosynostosis: Current and Potential Use Cases.

Three-dimensional (3D) stereophotogrammetry is a novel imaging technique that has gained popularity in the medical field as a reliable, non-invasive, and radiation-free imaging modality. It uses optical sensors to acquire multiple 2D images from different angles which are reconstructed into a 3D digital model of the subject's surface. The technique proved to be especially useful in craniofacial applications, where it serves as a tool to overcome the limitations imposed by conventional imaging modalities and subjective evaluation methods. The capability to acquire high-dimensional data in a quick and safe manner and archive them for retrospective longitudinal analyses, provides the field with a methodology to increase the understanding of the morphological development of the cranium, its growth patterns and the effect of different treatments over time.This review describes the role of 3D stereophotogrammetry in the evaluation of craniosynostosis, including reliability studies, current and potential clinical use cases, and practical challenges. Finally, developments within the research field are analyzed by means of bibliometric networks, depicting prominent research topics, authors, and institutions, to stimulate new ideas and collaborations in the field of craniofacial 3D stereophotogrammetry.We anticipate that utilization of this modality's full potential requires a global effort in terms of collaborations, data sharing, standardization, and harmonization. Such developments can facilitate larger studies and novel deep learning methods that can aid in reaching an objective consensus regarding the most effective treatments for patients with craniosynostosis and other craniofacial anomalies, and to increase our understanding of these complex dysmorphologies and associated phenotypes.

The Bone-Forming Properties of Periosteum-Derived Cells Differ Between Harvest Sites.

The development of alternatives for autologous bone grafts is a major focus of bone tissue engineering. To produce living bone-forming implants, skeletal stem and progenitor cells (SSPCs) are envisioned as key ingredients. SSPCs can be obtained from different tissues including bone marrow, adipose tissue, dental pulp, and periosteum. Human periosteum-derived cells (hPDCs) exhibit progenitor cell characteristics and have well-documented in vivo bone formation potency. Here, we have characterized and compared hPDCs derived from tibia with craniofacial hPDCs, from maxilla and mandible, respectively, each representing a potential source for cell-based tissue engineered implants for craniofacial applications. Maxilla and mandible-derived hPDCs display similar growth curves as tibial hPDCs, with equal trilineage differentiation potential toward chondrogenic, osteogenic, and adipogenic cells. These craniofacial hPDCs are positive for SSPC-markers CD73, CD164, and Podoplanin (PDPN), and negative for CD146, hematopoietic and endothelial lineage markers. Bulk RNA-sequencing identified genes that are differentially expressed between the three sources of hPDC. In particular, differential expression was found for genes of the HOX and DLX family, for SOX9 and genes involved in skeletal system development. The in vivo bone formation, 8 weeks after ectopic implantation in nude mice, was observed in constructs seeded with tibial and mandibular hPDCs. Taken together, we provide evidence that hPDCs show different profiles and properties according to their anatomical origin, and that craniofacial hPDCs are potential sources for cell-based bone tissue engineering strategies. The mandible-derived hPDCs display - both in vitro and in vivo - chondrogenic and osteogenic differentiation potential, which supports their future testing for use in craniofacial bone regeneration applications.

Assessing the Radiological Density and Accuracy of Mandible Polymer Anatomical Structures Manufactured Using 3D Printing Technologies.

Nowadays, 3D printing technologies are among the rapidly developing technologies applied to manufacture even the most geometrically complex models, however no techniques dominate in the area of craniofacial applications. This study included 12 different anatomical structures of the mandible, which were obtained during the process of reconstructing data from the Siemens Somatom Sensation Open 40 system. The manufacturing process used for the 12 structures involved the use of 8 3D printers and 12 different polymer materials. Verification of the accuracy and radiological density was performed with the CT160Xi Benchtop tomography system. The most accurate results were obtained in the case of models manufactured using the following materials: E-Model (Standard Deviation (SD) = 0.145 mm), FullCure 830 (SD = 0.188 mm), VeroClear (SD = 0.128 mm), Digital ABS-Ivory (SD = 0.117 mm), and E-Partial (SD = 0.129 mm). In the case of radiological density, ABS-M30 was similar to spongious bone, PC-10 was similar to the liver, and Polylactic acid (PLA) and Polyethylene terephthalate (PET) were similar to the spleen. Acrylic resin materials were able to imitate the pancreas, kidney, brain, and heart. The presented results constitute valuable guidelines that may improve currently used radiological phantoms and may provide support to surgeons in the process of performing more precise treatments within the mandible area.

Biodegradable magnesium alloy (WE43) in bone-fixation plate and screw.

The purpose of the present study was to evaluate the mechanical strength and the absorption rate of WE43 material and to develop an absorbable metallic plate and screw for craniofacial application. The extruded WE43 plate and screw were evaluated using a LeFort I osteotomy canine model of 10 beagle dogs. Animals were divided into two groups: five dogs in the experimental group and five dogs in the control group. μCT was acquired at 4, 12, and 24 weeks. At 24 weeks after the operation, all animals were sacrificed, and histologic evaluation was performed. Swelling and gas formation were observed in three dogs in the experimental groups at 8 weeks. From 12 weeks, infraorbital fistula and inflammation were observed in three dogs in the experimental group, which gradually decreased and disappeared at 24 weeks. Other two dogs showed less gas formation at 12 weeks. The plates were completely absorbed, and gas formation was not observed at 24 weeks in these two dogs. New bone was well formed around the plates and screws in both groups. Histologic examination showed no specific differences between two groups. The mechanical strength of extruded WE43 was sufficient for mid‐facial application. Plates and screws made with appropriately treated WE43 have the potential to be useful clinically.

Challenges for computer aided diagnostics using X-ray and tomographic reconstruction images in craniofacial applications

Computer-aided diagnostic systems are very important and crucial for patient's diagnosis and treatment planning. To automate such systems requires the combination of various different steps involved in the system. The variation in the process may make the system failure. Therefore, it is a need to analyse the system's workflow and to work on the challenges embedded in it. Imaging and automation challenges regarding computer-aided diagnosis are discussed in this paper. Each challenge is introduced within a computer-aided diagnosis (CAD) system of craniofacial applications. The significance and importance of every challenge are described in the paper. The method to overcome the challenges and issues are also discussed as an advantage for the readers of the paper.

Challenges for computer aided diagnostics using X-ray and tomographic reconstruction images in craniofacial applications

Challenges for computer aided diagnostics using X-ray and tomographic reconstruction images in craniofacial applications

Peripheral Nerve Stimulation for Facial Pain Using Wireless Devices.

Since its original introduction several decades ago, peripheral nerve stimulation (PNS) of the craniofacial region has been traditionally performed using devices intended for spinal cord stimulation applications with inevitably high rate of technical challenges and procedural complications. The lower invasiveness of recently developed wireless neurostimulation systems makes them much better suited for craniofacial applications. Here, we discuss the preliminary clinical data from several published reports and the ongoing multicenter prospective study of wireless PNS in the craniofacial region. Advances in wireless transmission of electrical signals may make wireless neurostimulation even more attractive in the future. Since most of the evidence supporting PNS for facial pain comes from small subsets of the population, case series and case reports, there will need to be larger, randomized controlled trials with cost efficacy analyses in order to validate the role of wireless PNS as the standard of care.

Bone Morphogenetic Protein-9-Stimulated Adipocyte-Derived Mesenchymal Progenitors Entrapped in a Thermoresponsive Nanocomposite Scaffold Facilitate Cranial Defect Repair.

Due to availability and ease of harvest, adipose tissue is a favorable source of progenitor cells in regenerative medicine, but has yet to be optimized for osteogenic differentiation. The purpose of this study was to test cranial bone healing in a surgical defect model utilizing bone morphogenetic protein-9 (BMP-9) transduced immortalized murine adipocyte (iMAD) progenitor cells in a citrate-based, phase-changing, poly(polyethylene glycol citrate-co-N-isopropylacrylamide) (PPCN)-gelatin scaffold. Mesenchymal progenitor iMAD cells were transduced with adenovirus expressing either BMP-9 or green fluorescent protein control. Twelve mice underwent craniectomy to achieve a critical-sized cranial defect. The iMAD cells were mixed with the PPCN-gelatin scaffold and injected into the defects. MicroCT imaging was performed in 2-week intervals for 12 weeks to track defect healing. Histologic analysis was performed on skull sections harvested after the final imaging at 12 weeks to assess quality and maturity of newly formed bone. Both the BMP-9 group and control group had similar initial defect sizes (P = 0.21). At each time point, the BMP-9 group demonstrated smaller defect size, higher percentage defect healed, and larger percentage defect change over time. At the end of the 12-week period, the BMP-9 group demonstrated mean defect closure of 27.39%, while the control group showed only a 9.89% defect closure (P < 0.05). The BMP-9-transduced iMADs combined with a PPCN-gelatin scaffold promote in vivo osteogenesis and exhibited significantly greater osteogenesis compared to control. Adipose-derived iMADs are a promising source of mesenchymal stem cells for further studies in regenerative medicine, specifically bone engineering with the aim of potential craniofacial applications.

Chitosan/Dextran Hydrogel Constructs Containing Strontium-Doped Hydroxyapatite with Enhanced Osteogenic Potential in Rat Cranium.

It is an effective way in bone tissue engineering to promote the mechanical and osteogenic capability of hydrogels by encapsulating mineral particles into polymer matrix. In this work, we reported novel kinds of nanocomposite scaffolds based on hydroxypropyl chitosan/aldehyde dextran hydrogel (CDH) and strontium-nanohydroxyapatite (Sr-nHA) nanoparticles. The molar ratios of Sr/(Sr + Ca) at 0% (nHA), 50% (Sr50nHA), and 100% (Sr100nHA) were fabricated and subsequently incorporated into CDH. The characterization of Sr-nHA/CDH constructs and CDH alone was studied by Fourier transform infrared analysis, X-ray powder diffraction detection, and scanning electron microscopy. The physical properties of hydrogels were further detected by swelling studies, degradation behavior, rheological measurements, mechanical testing, and ion-release behavior. Cell biocompatibility on the scaffolds was determined in vitro, and bone formation in vivo was examined by a rat calvarium defect model. The results showed that either nHA or Sr-nHA nanoparticles incorporation into CDH would significantly improve the rheological and mechanical properties (P < 0.05). The Sr2+ released from the Sr100nHA/CDH was in the range of optimal concentration for pro-osteogenesis. The addition of Sr-nHA significantly enhanced the cell proliferation and osteogenic differentiation of osteoblasts (P < 0.05). The Sr100nHA/CDH exerted the highest promotion on the polarization of macrophages toward the M2 phenotype. The new bone formation of Sr100nHA/CDH was 2.5-fold and 2-fold higher than that of CDH at 4 and 8 weeks, respectively (P < 0.05). HE staining, Masson's trichrome staining, and immunofluorescence staining of OCN results also confirmed that Sr100nHA/CDH had superior bone regeneration compared to other hydrogels in vivo. In conclusion, this novel in situ gelling hydrogel based on injectable and load-bearing 100% Sr-substituted nHA in CDH is expected to have wide orthopedic, dental, and craniofacial applications to enhance bone regeneration.

First principles study of the elastic properties of magnesium and iron based bio-resorbable alloys

In the present study, the Density Functional Theory (DFT) implemented in the VASP package has been used to investigate the effects of alloying of different elements deemed biocompatible (Ca, Zn, Li, Zr, Y, Sr, Mn, Ag, RE) when introduced into the Mg and Fe crystal lattice. In particular, the study has been conducted to investigate the general elastic properties, such as bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio of various Mg- and Fe-based alloys, the results serving to identify candidate bio-resorbable materials potentially suitable for cardiovascular, bronchotracheal, orthopedic and craniofacial applications.

Calcium Phosphate Cement Paste Injection as a Fiducial Marker of Cervical Cancer

Calcium phosphate cement (CPC) is used to fill bone voids in dental, orthopedic, and craniofacial applications. This study evaluated CPC marker as an injectable non-metallic fiducial marker. Six patients received 3-5 injections of CPC paste placed at a depth of 10 mm into tumors of the cervix before treatment planning CT (TPCT). Patients were treated with external-beam radiotherapy (EBRT) and high-dose rate brachytherapy (BT). We investigated marker visibility on cone-beam CT (CBCT), T2-weighted MRI, and interfraction of the marker motion for cervical cancer patients. Of a total of 22 visible CPC markers at TPCT, 17 CPC markers were visible on the first CBCT. Excluding one patient, all markers were visible on CBCT during EBRT. Of 16 visible CPC markers on CBCT, 13 CPC markers were visible on the magnetic resonance imaging (MRI) obtained before BT. For CPC marker centroid movement, the mean-of-means/systematic variation/random variation were 0.2/0.4/1.4, -1.6/5.1/4.1, and -3.4/2.1/2.8 mm for the left-right, dorsal-ventral, and cranial-caudal directions, respectively. This is the first report of a CPC marker injected into tumors of the cervix. It can be visualized on CBCT and MRI with reductions in marker loss and artifacts.

Electrospun 3D composite scaffolds for craniofacial critical size defects.

Critical size defects in the craniofacial region can be effectively treated using three dimensional (3D) composite structures mimicking natural extra cellular matrix (ECM) and incorporated with bioactive ceramics. In this study we have shown that the dynamic liquid bath collector can be used to form electrospun polycaprolactone (PCL)-hydroxyapatite (HA) composite structure as unique 3D scaffold. The structure was found to have three distinct sections (base, stem and head) based on the mechanism of its formation and morphology. The size of the head portion was around 15 mm and was found to vary with the process parameters. Scanning electron microscopy (SEM) analysis revealed that the base had random fibres while the fibres in stem and head sections were aligned but perpendicular to each other. X-ray diffraction (XRD) analysis also showed an increase in the crystallinity index of the fibres from base to head section. Cytotoxicity and cytocompatibility studies using human osteosarcoma (HOS) cells showed good cell adhesion and proliferation indicating the suitability of the 3D structure for craniofacial graft applications.

Colloidal Gels with Extracellular Matrix Particles and Growth Factors for Bone Regeneration in Critical Size Rat Calvarial Defects.

Colloidal gels encapsulating natural materials and exhibiting paste-like properties for placement are promising for filling complex geometries in craniofacial bone regeneration applications. Colloidal materials have demonstrated modest clinical outcomes as bone substitutes in orthopedic applications, but limited success in craniofacial applications. As such, development of a novel colloidal gel will fill a void in commercially available products for use in craniofacial reconstruction. One likely application for this technology is cranial reconstruction. Currently, traumatic brain injury (TBI) is often treated with a hemi-craniectomy, a procedure in which half the cranium is removed to allow the injured brain to swell and herniate beyond the enclosed cranial vault. The use of colloidal gels would allow for the design of a pliable material capable of expansion during brain swelling and facilitate cranial bone regeneration alleviating the need for a second surgery to replace the previously removed hemi-cranium. In the current study, colloidal nanoparticles of hydroxyapatite (HAp), demineralized bone matrix (DBM), and decellularized cartilage (DCC) were combined with hyaluronic acid (HA) to form colloidal gels with desirable rheological properties ([Formula: see text] ≥ 100Pa). BMP-2 and VEGF growth factors were included to assess extracellular matrix (ECM) contribution of DBM and DCC. The HA-HAp (BMP-2) and HA-HAp-DCC group had 89 and 82% higher bone regeneration compared to the sham group, respectively (p < 0.01). Material retention issues observed may be alleviated by implementing chemical crosslinking. Overall, DCC may be a promising material for bone regeneration in general, and colloidal gels may hold significant potential in craniofacial applications.

Current Developments in 3D Printing for Craniofacial Regeneration

Three dimensional printing, or additive manufacturing, allows the production of customized scaffolds that can enhance craniofacial reconstruction and regeneration. It can be achieved by several techniques, including selective laser sintering, electron beam melting, fused deposition melting, fused filament fabrication, as well as extrusion and laser-assisted bioprinting of cells. 3D-printed constructs can take the form of nonresorbable solid form prosthesis or porous degradable scaffolds that can be resorbed over time and replaced by native tissues. The later can be considered the more desirable outcome but it is also more challenging to achieve. 3D-printed constructs have been used in a variety of oro-dental and craniofacial applications, including vertical bone augmentation, mandibular, and skull defect reconstruction, periodontal regeneration, and temporomandibular joint replacement. Although considerable advancements have been made, challenges remain in translating this technology to the clinic, especially in producing customized, porous, and inter-connected scaffolds for the regeneration of complex multiphasic tissues of varying dimensions ranging from a few millimeters to several centimeters.