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The purpose of this paper is to design and development of a patient-specific implant for zygomatic area of a patient suffering from mucormycosis (fungal infection). The paper describes how integration of computer-aided design (CAD) and 3D printing can be successfully used for developing custom implants for the sites for which readymade optimal solutions are not available.

The CT scan data of the patient were used for the generation of a 3D model. The healthy side of skull was mirrored and copied on the infected part, which served as a base for designing the implant. The prototype of the implant was printed using fused deposition modelling before finally printing in Ti6Al4V alloy using direct metal laser sintering process.

The custom designed implant fitted well to the patient’s skull during surgery. Proper facial aesthetics were maintained post-surgery.

The work describes the application of CAD-based image processing software and additive manufacturing in the development of a custom implant for the sites for which no readymade optimal solution is available.

Chest wall reconstruction of large oncological defects following resection is challenging. Traditional management involves the use of different materials that surgeons creatively shape intraoperatively to restore the excised anatomy. This is time-consuming, difficult to mould into shape and causes some complications such as dislocation or paradoxical movement. This study aims to present the development and clinical implantation of a novel custom-made three-dimensional (3D) laser melting titanium alloy implant that reconstructs a large chest wall resection and maintains the integrity of the thoracic cage.

The whole development process of the novel implant is described: design specifications, computed tomography (CT) scan manipulation, 3D computer-assisted design (CAD), rapid prototyping, final manufacture and clinical implantation. A multidisciplinary collaboration in between engineers and surgeons guided the iterative design process.

The implant provided excellent aesthetical and functional results. The virtual planning and production of the implant prior to surgery reduced surgery time and uncertainty. It also improved safety and accuracy. The implant sited nicely on the patient anatomy after resection following the virtual plan. At six months following implantation, there were no implant-related complications of pain, infection, dislocation or paradoxical movement. This technique offered a fast lead-time for implant production, which is crucial for oncological treatment.

More cases and a long-term follow-up are needed to confirm and quantify the benefits of this procedure; further research is also required to design a solution that better mimics the chest wall biomechanics while preventing implant complications.

The authors present a novel custom thoracic implant that provided a satisfactory reconstruction of a large chest wall defect, developed and implanted within three weeks to address a fast-growing chondrosarcoma. Furthermore, the authors describe its development process in detail as a design guideline, discussing potential improvements and critical design considerations so that this study can be replicated for future cases.

To develop a computer‐assisted prefabricated implant design and manufacturing system to improve the esthetic outcome in chin surgery.

Design methods for medical rapid prototyping (RP) of custom‐fabricated chin augmentation implant are presented in this paper. After a careful preoperative planning based on cephalometric tracing for esthetic assessment, helical computed tomography data were used to create a three‐dimensional model of the deficient mandible. Based on these data, the inner surface of the prosthesis was designed to fit the bone surface exactly. The outer geometry was generated from a dried human mandible to create anatomically correct shape prosthesis. The inner and outer surfaces were then connected, and a solid model resulted. A RP system was used for production of the physical models. The surgical planning was performed using the implants and skull models. The resulting SLA implant is used for the production of a mold, which is used to cast the titanium part. Three patients with a congenital small chin or a small and asymmetric mandible underwent reconstruction with individual prefabricated implant. Mean follow‐up period was 1.5 years.

This approach showed significant results in chin augmentation. Compared with traditional methods, the intra‐operative fit was excellent. The operating time was reduced. Postoperatively, the patients experienced the restoration of a natural chin contour, so the esthetic outcome was pleasing. Over the mean follow‐up period of 1.5 years, there were no complications and no implant had to be removed. Long‐term excellent esthetic outcomes by using this new technique have recently been reported.

The methods described above suffer from certain limitations. The registration of the mandible template to create the augmentation image requires high skills of the designer. In addition, the use of RP model in preoperative preparation is expensive.

This method not only demonstrates the significant progress in the reconstruction of chin defects using CAD/CAM RP and RT, compared with the conventional methods of chin augmentation surgery, but also provides natural geometrical prosthesis contour design and accurate fabrication and precise fitting of the prosthesis. The advantages of using this technique are that the physical model of the implant is fitted on the skull model so that the surgeon can plan and rehearse the surgery in advance and a less invasive surgical procedure and less time‐consuming reconstructive and an adequate esthetic can result.

This clinical case demonstrated the potential value of CAD/CAM and RP‐based custom fitted and anatomically correct shape prosthesis fabrication and presurgical planning in craniofacial surgery.

Post-traumatic zygomatic osteotomy, fracture reduction, and orbital floor reconstruction pose many challenges for achieving a predictable, accurate, safe, and aesthetically pleasing result. This paper aims to describe the successful application of computer-aided design (CAD) and additive manufacturing (AM) to every stage of the process – from planning to surgery.

A multi-disciplinary team was used – comprising surgeons, prosthetists, technicians, and designers. The patient’s computed tomography scan data were segmented for bone and exported to a CAD software package. Medical models were fabricated using AM; for diagnosis, patient communication, and device verification. The surgical approach was modelled in the virtual environment and a custom surgical cutting guide, custom bone-repositioning guide, custom zygomatic implant, and custom orbital floor implant were each designed, prototyped, iterated, and validated using polymer AM prior to final fabrication using metal AM.

Post-operative clinical outcomes were as planned. The patient’s facial symmetry was improved, and their inability to fully close their eyelid was corrected. The length of the operation was reduced relative to the surgical team’s previous experiences. Post-operative scan analysis indicated a maximum deviation from the planned location for the largest piece of mobilised bone of 3.65 mm. As a result, the orbital floor implant which was fixed to this bone demonstrated a maximum deviation of 4.44 mm from the plan.

This represents the first application of CAD and AM to every stage of the process for this procedure – from diagnosis, to planning, and to surgery.

The aim of this study is to describe an improved experimental substrate for the mechanical testing of patient-specific implants fabricated using direct metal additive manufacturing processes. This method reduces variability and sample size requirements and addresses the importance of geometry at the bone/implant interface.

Short-fiber glass/resin materials for cortical bone and polyurethane foam materials for cancellous bone were evaluated using standard tensile coupons. A method for fabricating bone analogs with patient-specific geometries using rapid tooling is presented. Bone analogs of a canine radius were fabricated and compared to cadaveric specimens in several biomechanical tests as validation.

The analog materials exhibit a tensile modulus that falls within the range of expected values for cortical and cancellous bone. The tensile properties of the cortical bone analog vary with fiber loading. The canine radius models exhibited similar mechanical properties to the cadaveric specimens with a reduced variability.

Additional replications involving different bone geometries, types of bone and/or implants are required for a full validation. Further, the materials used here are only intended to mimic the mechanical properties of bone on a macro scale within a relatively narrow range. These analog models have not been shown to address the complex microscopic or viscoelastic behavior of bone in the present study.

Scientific data on the formulation and fabrication of bone analogs are absent from the literature. The literature also lacks an experimental platform that matches patient-specific implant/bone geometries at the bone implant interface.

The purpose of this paper is to establish a methodology for the design and development of patient-specific elbow implant with an elastic modulus close to that of the human bone. One of the most preferred implant material is titanium alloy which is about 8 to 9 times higher in strength than that of the human bone and is the closest than other metallic biomedical materials.

The methodology begins with the design of the implant from patient-specific computed tomography information and incorporates the manufacturing of the implant via a novel rapid prototyping assisted microwave sintering process.

The elastic modulus and the flexural strength of the implant were observed to be comparable to that of human elbow bones. The fatigue test depicts that the implant survives the one million cycles under physiological loading conditions. Other mechanical properties such as impact energy absorption, hardness and life cycle tests were also evaluated. The implant surface promotes human cell growth and adhesion and does not cause any adverse or undesired effects i.e. no cytotoxicity.

Stress shielding, and therefore, aseptic loosening of the implant shall be avoided. In the event of any trauma post-implantation, the implant would not hurt the patient.

The present study describes a methodology for the first time to be able to obtain the strength required for the medical implant without sacrificing the fatigue life requirement.

The purpose of this paper was to present how customized implants could be made with specific properties, by setting different values of the laser power, within the selective laser melting (SLM) process. A detailed case study was undertaken and a new multi-structured femoral prosthesis was designed and analyzed, to simulate its behavior for a specific case study.

The materials and manufacturing methods are presented, with details regarding the SLM process, using the Realizer 250 machine. The laser power was varied between 50 and 200 W, thus obtaining samples with different physical and mechanical characteristics. All those sample parts were characterized and their properties were measured.

A practical methodology was found to produce multi-structured implants by SLM. Significant changes of the porosity and properties were found, when modifying the laser power at the SLM machine. The studies have indicated an open porosity varying between 24.810.83 per cent. Tensile tests of the samples showed Young’s modulus values varying between 13.5 and 104.5 GPa and an ultimate stress between 20.2 and 497.5 MPa.

There is no Additive Manufacturing (AM) machine available, to work with different laser power values, in different regions of the same section of the implant. Hence, a multi-structured implant cannot be obtained directly.

The prosthesis should be specifically designed to contain separate models/regions to be made with appropriate laser power values.

This paper presents a new method to design and manufacture a multi-structured implant, using the existing AM equipment. A detailed case study is presented, showing the design procedure, the way to simulate its behavior and the methods to produce the implants by SLM.

Three-dimensional (3D) printing technologies have gained attention in dentistry because of their ability to print objects with complex geometries with high precision and accuracy, as well as the benefits of saving materials and treatment time. This study aims to explain the principles of the main 3D printing technologies used for manufacturing dental prostheses and devices, with details of their manufacturing processes and characteristics. This review presents an overview of available 3D printing technologies and materials for dental prostheses and devices.

This review was targeted to include publications pertaining to the fabrication of dental prostheses and devices by 3D printing technologies between 2012 and 2021. A literature search was carried out using the Web of Science, PubMed, Google Scholar search engines, as well as the use of a manual search.

3D printing technologies have been used for manufacturing dental prostheses and devices using a wide range of materials, including polymers, metals and ceramics. 3D printing technologies have demonstrated promising experimental outcomes for the fabrication of dental prostheses and devices. However, further developments in the materials for fixed dental prostheses are required.

3D printing technologies are effective and commercially available for the manufacturing of polymeric and metallic dental prostheses. Although the printing of dental ceramics and composites for dental prostheses is promising, further improvements are required.

The purpose of this paper is to investigate the use of medical‐grade polymethylmethacrylate (PMMA) in fused deposition modeling (FDM) to fabricate porous customized freeform structures for several applications including craniofacial reconstruction and orthopaedic spacers. It also aims to examine the effects of different fabrication conditions on porosity and mechanical properties of PMMA samples.

The building parameters and procedures to properly and consistently extrude PMMA filament in FDM for building 3D structures were determined. Two experiments were performed that examined the effects of different fabrication conditions, including tip wipe frequency, layer orientation, and air gap (AG) (or distance between filament edges) on the mechanical properties and porosity of the fabricated structures. The samples were characterized through optical micrographs, and measurements of weight and dimensions of the samples were used to calculate porosity. The yield strength, strain, and modulus of elasticity of the samples were determined through compressive testing.

Results show that both the tip wipe frequency (one wipe every layer or one wipe every ten layers) and layer orientation (transverse or axial with respect to the applied compressive load) used to fabricate the scaffolds have effects on the mechanical properties and resulting porosity. The samples fabricate in the transverse orientation with the high tip wipe frequency have a larger compressive strength and modulus than the lower tip wipe frequency samples (compressive strength: 16±0.97 vs 13±0.71 MPa, modulus: 370±14 vs 313±29 MPa, for the high vs low tip wipe frequency, respectively). Also, the samples fabricated in the transverse orientation have a larger compressive strength and modulus than the ones fabricated in the axial orientation (compressive strength: 16±0.97 vs 13±0.83 MPa, modulus: 370±14 vs 281±22 MPa; for samples fabricated with one tip wipe per layer in the transverse and axial orientations, respectively). In general, the stiffness and yield strength decreased when the porosity increased (compressive strength: 12±0.71 to 7±0.95 MPa, Modulus: 248±10 to 165±16 MPa, for samples with a porosity ranging from 55 to 70 percent). As a demonstration, FDM is successfully used to fabricate patient‐specific, 3D PMMA implants with varying densities, including cranial defect repair and femur models.

This paper demonstrates that customized, 3D, biocompatible PMMA structures with varying porosities can be designed and directly fabricated using FDM. By enabling the use of PMMA in FDM, medical implants such as custom craniofacial implants can be directly fabricated from medical imaging data improving the current state of PMMA use in medicine.

Three-dimensional (3D) printing is increasingly used to produce orthopaedic components for hip arthroplasty, such as acetabular cups, which show complex lattice porous structures and shapes. However, limitations on the quality of the final implants are present; thus, investigations are needed to ensure adequate quality and patients safety. X-ray microcomputed tomography (micro-CT) has been recognised to be the most suitable method to evaluate the complexity of 3D-printed parts. The purpose of this study was to assess the reliability of a micro-CT analysis method comparing it with reference systems, such as coordinate measuring machine and electron microscopy.

3D-printed acetabular components for hip arthroplasty (n = 2) were investigated. Dimensions related to the dense and porous regions of the samples were measured. The micro-CT scanning parameters (voltage – kV, current – µA) were optimised selecting six combinations of beam voltage and current.

Micro-CT showed good correlation and agreement with both coordinate measuring machine and scanning electron microscopy when optimal scanning parameters were selected (130 kV – 100 µA to 180 kV – 80 µA). Mean discrepancies of 50 µm (± 300) and 20 µm (± 60) were found between the techniques for dense and porous dimensions. Investigation method such as micro-CT imaging may help to better understand the impact of 3D printing manufacturing technology on the properties of orthopaedic implants.

The optimisation of the scanning parameters and the validation of this method with reference techniques may guide further analysis of similar orthopaedic components.