International Journal of Computerized Dentistry, 04/2016

The beginnings of three-dimensional (3D) printing and bioprinting can be traced to as early as 1984. From printing inorganic models for the generation of biologic scaffolds, additive manufacturing (AM) developed to the direct printing of organic materials, including specialized tissues, proteins, and cells. In recent years, these technologies have gained significantly in relevance, and there have been several innovations, especially in the field of regenerative medicine. It is becoming increasingly important to consider the economic and social aspects of AM, particularly in education and information of medical human resources, society, and politics, as well as for the establishment of homogenous, globally adapted legal regulations. Keywords: 3D printing, bioprinting, additive manufacturing, regenerative medicine, history of bioprinting, legal regulation, social aspects

The structural and functional repair of lost bone is still one of the biggest challenges in regenerative medicine. In many cases, autologous bone is used for the reconstruction of bone tissue; however, the availability of autologous material is limited, which always means additional stress to the patient. Due to this, more and more frequently various biocompatible materials are being used instead for bone augmentation. In this context, in order to ensure the structural function of the bone, scaffolds are implanted and fixed into the bone defect, depending on the medical indication. Nevertheless, for the surgeon, every individual clinical condition in which standardized scaffolds have to be aligned is challenging, and in many cases the alignment is not possible without limitations. Therefore, in the last decades, 3D printing (3DP) or additive manufacturing (AM) of scaffolds has become one of the most innovative approaches in surgery to individualize and improve the treatment of patients. Numerous biocompatible materials are available for 3DP, and various printing techniques can be applied, depending on the process conditions of these materials. Besides these conventional printing techniques, another promising approach in the context of medical AM is 3D bioprinting, a technique which makes it possible to print human cells embedded in special carrier substances to generate functional tissues. Even the direct printing into bone defects or lesions becomes possible. 3DP is already improving the treatment of patients, and has the potential to revolutionize regenerative medicine in future. Keywords: 3D printing (3DP), additive manufacturing (AM), bioprinting, bone regeneration, regenerative medicine, scaffolds, biocompatible materials

Already three decades ago, the potential of medical 3D printing (3DP) or rapid prototyping for improved patient treatment began to be recognized. Since then, more and more medical indications in different surgical disciplines have been improved by using this new technique. Numerous examples have demonstrated the enormous benefit of 3DP in the medical care of patients by, for example, planning complex surgical interventions preoperatively, reducing implantation steps and anesthesia times, and helping with intraoperative orientation. At the beginning of every individual 3D model, patient-specific data on the basis of computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound data is generated, which is then digitalized and processed using computer-aided design/computer-aided manufacturing (CAD/CAM) software. Finally, the resulting data sets are used to generate 3D-printed models or even implants. There are a variety of different application areas in the various medical fields, eg, drill or positioning templates, or surgical guides in maxillofacial surgery, or patient-specific implants in orthopedics. Furthermore, in vascular surgery it is possible to visualize pathologies such as aortic aneurysms so as to improve the planning of surgical treatment. Although rapid prototyping of individual models and implants is already applied very successfully in regenerative medicine, most of the materials used for 3DP are not yet suitable for implantation in the body. Therefore, it will be necessary in future to develop novel therapy approaches and design new materials in order to completely reconstruct natural tissue. Keywords: 3D printing, rapid prototyping, patient-specific, individual implants, maxillofacial surgery, orthopedics, vascular surgery

Several aspects of digital dentistry have recently been improved, including new materials, navigated implant placement, digital impression in combination with virtual articulation, and the computer-aided processes of designing and manufacturing of prosthetic restorations. In this case report, the prosthodontic treatment of a patient through a complete digital workflow is presented. A 39-year-old male patient presented for restoration of missing teeth in the posterior maxilla and mandible. In a single-tooth narrow gap (region 15), a Straumann NNC implant was placed by computer-assisted planning and navigation. For the rest of the missing teeth, ZrO2 fixed dental prostheses (FDPs) were manufactured by a computer-aided design/computer- aided manufacturing (CAD/CAM) system after optical impression with an intraoral scanner (iTero), and data transferal to a virtual articulator (Ceramill Artex). Rehabilitation through a complete digital workflow is a promising technology in terms of accuracy, reduced workload, greater control over the final product, and minimally invasive procedures. These advantages may have a potential positive effect with regard to patient satisfaction compared with conventional methods. Keywords: digital dentistry, intraoral scanner, virtual articulator, navigated implant placement, ceramic restorations

Today, orthodontic treatment with fixed appliances is usually carried out using preprogrammed straight-wire brackets made of metal or ceramics. Objective: The goal of this study was to determine the possibility of clinically implementing a fully digital workflow with individually designed and three-dimensionally printed (3D-printed) brackets. Materials and methods: Edgewise brackets were designed using computer-aided design (CAD) software for demonstration purposes. After segmentation of the malocclusion model generated based on intraoral scan data, the brackets were digitally positioned on the teeth and a target occlusion model created. The thus-defined tooth position was used to generate a template for an individualized arch form in the horizontal plane. The base contours of the brackets were modified to match the shape of the tooth surfaces, and a positioning guide (fabricated beforehand) was used to ensure that the brackets were bonded at the correct angle and position. The brackets, positioning guide, and retainer splint, digitally designed on the target occlusion model, were 3D printed using a Digital Light Processing (DLP) 3D printer. The archwires were individually pre-bent using the template. Results: In the treatment sequence, it was shown for the first time that, in principle, it is possible to perform treatment with an individualized 3D-printed brackets system by using the proposed fully digital workflow. Technical aspects of the system, problems encountered in treatment, and possible future developments are discussed in this article. Keywords: orthodontic treatment, digital workflow, 3D-printed brackets