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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.

The purpose of this paper is to investigate the performance of chaotic gravitational search algorithm (CGSA) in solving mechanical engineering design frameworks including welded beam design (WBD), compression spring design (CSD) and pressure vessel design (PVD).

In this study, ten chaotic maps were combined with gravitational constant to increase the exploitation power of gravitational search algorithm (GSA). Also, CGSA has been used for maintaining the adaptive capability of gravitational constant. Furthermore, chaotic maps were used for overcoming premature convergence and stagnation in local minima problems of standard GSA.

The chaotic maps have shown efficient performance for WBD and PVD problems. Further, they have depicted competitive results for CSD framework. Moreover, the experimental results indicate that CGSA shows efficient performance in terms of convergence speed, cost function minimization, design variable optimization and successful constraint handling as compared to other participating algorithms.

The use of chaotic maps in standard GSA is a new beginning for research in GSA particularly convergence and time complexity analysis. Moreover, CGSA can be used for solving the infinite impulsive response (IIR) parameter tuning and economic load dispatch problems in electrical sciences.

The hybridization of chaotic maps and evolutionary algorithms for solving practical engineering problems is an emerging topic in metaheuristics. In the literature, it can be seen that researchers have used some chaotic maps such as a logistic map, Gauss map and a sinusoidal map more rigorously than other maps. However, this work uses ten different chaotic maps for engineering design optimization. In addition, non-parametric statistical test, namely, Wilcoxon rank-sum test, was carried out at 5% significance level to statistically validate the simulation results. Besides, 11 state-of-the-art metaheuristic algorithms were used for comparative analysis of the experimental results to further raise the authenticity of the experimental setup.

To fabricate the self‐hardening calcium phosphate composite scaffolds with controlled internal pore architectures using rapid prototyping (RP) techniques and investigate their in vitro bone tissue engineering responses.

The three‐dimensionally interconnected pores in scaffolds can facilitate sufficient supply of blood, oxygen and nutrients for the ingrowth of bone cells, tissue regeneration, and vascularization. It is essential for bone tissue engineering to provide an accurate control over the scaffolds material, porosity, and internal pore architectures. Negative image of scaffold was designed and epoxy resin molds were fabricated on sterolithography apparatus. Calcium phosphate cement slurry was cast in these molds. After self‐hardening, the molds were removed by pyrolysis and the resulting scaffolds were obtained.

Eight scaffolds with 54.45 percent porosity were tested on an Instron machine. The average compressive strength measured was 5.8±0.8 Mpa. Cytotoxicity and cell proliferation studies were conducted with rabbit osteoblast. Results showed that these scaffolds were non‐toxic and displayed excellent cell growth during the 2 weeks of in vitro culture.

The resulting scaffolds inherited errors and defects from the molds, such as cracks and dimensional changes.

The present method enhances the versatility of scaffold fabrication by RP. It is capable of reproducibly fabricating scaffolds from a variety of biomaterials.

This paper describes computer‐aided design (CAD) and rapid prototyping (RP) systems for the fabrication of maxillofacial implant.

Design methods for medical RP of custom‐fabricated are presented in this paper. Helical computed tomography (CT) data were used to create a three‐dimensional model of the patient skull. Based on these data, the individual shape of the implant was designed in CAD environment and fabricate by RP process. One patient with a large mandible defect underwent reconstruction with individual prefabricated implant resulting from initial surgical failure with hand contoured reconstruction plate.

Results shows that the custom made implant fit well the defect. Overall, excellent mandible symmetry and stability were achieved with the custom made implants. The patient was able to eat. There was no saliva drooling after the reconstruction. The operating time was reduced.

The methods described above suffer from the expensive cost of RP technique.

This method allows accurate fabrication of the implant. 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.

The method improves the reconstructive surgery and reduces the risk of a second intervention, and the psychological stress of the patient will be eliminated.

This paper aims to describe computer‐aided design and rapid prototyping (RP) systems for the preoperative planning and fabrication of custom‐made implant.

A patient with mandible defect underwent reconstruction using custom‐made implant. 3D models of the patient's skull are generated based on computed tomography image data. After evaluation of the 3D reconstructed image, it was identified that some bone fragment was moved due to the missing segment. During the implant design process, the correct position of the bone fragment was defined and the geometry of the custom‐made implant was generated based on mirror image technique and is fabricated by a RP machine. Surgical approach such as preoperative planning and simulation of surgical procedures was performed using the fabricated skull models and custom‐made implant.

Results show that the stereolithography model provided an accurate tool for preoperative, surgical simulation.

The methods described above suffer from the expensive cost of RP technique.

This method allows accurate fabrication of the implant. 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.

The method improves the reconstructive surgery and reduces the risk of a second intervention, and the psychological stress of the patient will be eliminated.

The purpose of this paper is to demonstrate the route to digitize the customized mandible implants consisting of image acquisition, processing, implant design, fitting rehearsal and fabrication using fused deposition modeling and electron beam melting methodologies.

Recent advances in the field of rapid prototyping, reverse engineering, medical imaging and image processing have led to new heights in the medical applications of additive manufacturing (AM). AM has gained a lot of attention and interest during recent years because of its high potential in medical fields.

Produced mandible implants using casting, milling and machining are of standard sizes and shapes. As each person’s physique and anatomical bone structure are unique, these commercially produced standard implants are manually bent before surgery using trial and error methodology to custom fit the patient’s jaw. Any mismatch between the actual bone and the implant results in implant failure and psychological stress and pain to the patient.

The novelty in this paper is the construction of the customized mandibular implant from the computed tomography (CT) scan which includes surface reconstruction, implant design with validation and simulation of the mechanical behavior of the design implant using finite element analysis (FEA). There has been few research studies on the design and customization of the implants before surgery, but there had been hardly any study related to customized design implant and evaluating the biomechanical response on the newly designed implant using FEA. Though few studies are related to FEA on the reconstruction plates, but their paper lacks the implant design model and the reconstruction model. In this research study, an integrated framework is developed for the implant design, right from the CT scan of the patient including the softwares involved through out in the study and then performing the biomechanical study on the customized design implant to prove that the designed implant can withstand the biting and loading conditions. The proposed research methodology which includes the interactions between medical practitioners and the implant design engineers can be incorporated to any other reconstruction bone surgeries.

Today, medical models can be made by the use of medical imaging systems through modern image processing methods and rapid prototyping (RP) technology. In ultrasound imaging systems, as images are not layered and are of lower quality as compared to those of computerized tomography (CT) and magnetic resonance imaging (MRI), the process for making physical models requires a series of intermediate processes and it is a challenge to fabricate a model using ultrasound images due to the inherent limitations of the ultrasound imaging process. The purpose of this paper is to make high quality, physical models from medical ultrasound images by combining modern image processing methods and RP technology.

A novel and effective semi‐automatic method was developed to improve the quality of 2D image segmentation process. In this new method, a partial histogram of 2D images was used and ideal boundaries were obtained. A 3D model was achieved using the exact boundaries and then the 3D model was converted into the stereolithography (STL) format, suitable for RP fabrication. As a case study, the foetus was chosen for this application since ultrasonic imaging is commonly used for foetus imaging so as not to harm the baby. Finally, the 3D Printing (3DP) and PolyJet processes, two types of RP technique, were used to fabricate the 3D physical models.

The physical models made in this way proved to have sufficient quality and shortened the process time considerably.

It is still a challenge to fabricate an exact physical model using ultrasound images. Current commercial histogram‐based segmentation method is time‐consuming and results in a less than optimum 3D model quality. In this research work, a novel and effective semi‐automatic method was developed to select the threshold optimum value easily.

The purpose of this paper is to develop a workflow for 3D modeling and additive manufacturing (AM) of patient‐specific medical implants. The comprehensive workflow consists of four steps: medical imaging; 3D modelling; additive manufacturing; and clinical application. Implants are used to reconstruct bone damage or defects caused by trauma or disease. Traditionally, implants have been manually bent and shaped, either preoperatively or intraoperatively, with the help of anatomic solid models. The proposed workflow obviates the manual procedure and may result in more accurate and cost‐effective implants.

A patient‐specific implant was digitally designed to reconstruct a facial bone defect. Several test pieces were additive manufactured from stainless steel and titanium by direct metal laser sintering (DMLS) technology. An additive manufactured titanium EOS Titanium Ti64 ELI reconstruction plate was successfully implanted onto the patient's injured orbital wall.

This method enables exact fitting of implants to surrounding tissues. Creating implants before surgery improves accuracy, may reduce operation time and decrease patient morbidity, hence improving quality of surgery. By using AM methods it is possible to manufacture a volumetric net structure, which also allows cells and tissues to grow through it to and from surrounding tissues. The net is created from surface and its thickness and hole size are adjustable. The implant can be designed so that its mass is low and therefore sensitivity to hot and cold temperatures is reduced.

The paper describes a novel technique to create patient‐specific reconstruction implants for facial bony defects.

Combination of advanced imaging, designing and manufacturing techniques has been rapidly developed in recent years for diagnostic and therapeutic purposes for medical devices. The purpose of this paper is to present a methodology for design and fabrication procedure of medical models using computer‐aided design (CAD) and fused deposition modeling (FDM) technique for application in the mandibular reconstructive surgery.

Case studies of patients with mandibular defects are examined using CAD model construction including data acquisition from computerized tomography scan and data processing. Furthermore, the effect of advanced manufacturing parameters settings in FDM methodology is investigated.

The models were used in assisting the surgeons in their reconstruction planning. A significant improvement regarding the success and convenience in surgery planning been reported.

This paper explores the application and viability of FDM rapid prototyping technology for fabrication of complex mandibular models used for reconstructive surgery.

The purpose of this paper is to explore an application of computer‐aided design and manufacture (CAD/CAM) to a process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework.

With the introduction of laser scan technology and commercial reverse engineering software, a standard plaster maxillary dental cast with dentition defect was successfully scanned and created as a STL‐formatted digital cast. With the software, the unwanted undercuts were eliminated based on the desired path of insertion. Parts of the RPD framework were then successfully custom‐designed and combined as a whole.

A sacrificial pattern was produced by rapid prototyping (RP) method and finally casted with chromium cobalt alloy. With suitable finishing process, both the sacrificial pattern and the casted framework fitted the cast well.

The research indicated the feasibility of creating a library of RPD framework components. It is believed that, in the future, with the advance of the techniques, a totally new platform can be developed for the design and fabrication of custom‐fit RPD framework based on the CAD/CAM/RP system.