OBJECTIVE: To compare and report on the performance of implant-supported fixed dental prostheses (iFDPs) fabricated using additive (AM) or subtractive (SM) manufacturing.
METHODS: An electronic search was conducted (Medline, Embase, Cochrane Central, Epistemonikos, clinical trials registries) with a focused PICO question: In partially edentulous patients with missing single (or multiple) teeth undergoing dental implant therapy (P), do AM iFDPs (I) compared to SM iFDPs (C) result in improved clinical performance (O)? Included were studies comparing AM to SM iFDPs (randomized clinical trials, prospective/retrospective clinical studies, case series, in vitro studies).
RESULTS: Of 2\'184 citations, no clinical study met the inclusion criteria, whereas six in vitro studies proved to be eligible. Due to the lack of clinical studies and considerable heterogeneity across the studies, no meta-analysis could be performed. AM iFDPs were made of zirconia and polymers. For SM iFDPs, zirconia, lithium disilicate, resin-modified ceramics and different types of polymer-based materials were used. Performance was evaluated by assessing marginal and internal discrepancies and mechanical properties (fracture loads, bending moments). Three of the included studies examined the marginal and internal discrepancies of interim or definitive iFDPs, while four examined mechanical properties. Based on marginal and internal discrepancies as well as the mechanical properties of AM and SM iFDPs, the studies revealed inconclusive results.
CONCLUSIONS: Despite the development of AM and the comprehensive search, there is very limited data available on the performance of AM iFDPs and their comparison to SM techniques. Therefore, the clinical performance of iFDPs by AM remains to be elucidated.

BACKGROUND: In recent years, Three-dimensional printing (3-DP) technology, has had several applications in many fields of medicine, including rhinology. The aim of this review is to evaluate the use of 3-DP buttons as a treatment option for nasal septal perforations (NSP).
METHODS: We conducted a scoping review of the literature until June 07, 2022, on the online databases PubMed, Mendeley, and Cochrane Library. All articles referred to treatment of NSP with custom made buttons created by 3-DP technology were included in this study.
RESULTS: A total of 197 articles were generated by the search. Six articles met the inclusion criteria. 3 of the articles referred to clinical cases or clinical series. A total of 35 patients used the 3-DP custom made button as a treatment for NSP. The retention rate of this buttons ranged from 90.5 % to 100 %. An overall decrease in NSP symptoms was also observed in the majority of patients, especially regarding the most common complaints such as nasal bleeding and crusting.
CONCLUSIONS: The manufacturing of 3-DP buttons is a complex, time consuming process that requires both special laboratory equipment and trained staff. This method has the advantage of reducing the NSP related symptoms and an improving the retention rate. This could make the 3-DP custom made button a first-choice treatment for patients with NSP. However, as a new treatment option, it needs studies with more patients to determine its superiority over conventional buttons and its long-lasting therapeutic effects.

Neurosurgery is a demanding field with small margins of error within the operative field. Small errors can yield devastating consequences. Simulation has been proposed as a methodology for improving surgical skills within the neurosurgical realm. This study was conducted to investigate a novel realistic design for a clinical simulation based, low-cost alternative of external ventricular drain (EVD) placement, an essential basic neurosurgical procedure that is necessary for clinicians to master. A low-cost three-dimensional (3D) printed head using thermoplastic polylactic acid was designed with the tactile feedback of outer table, cancellous bone, and inner tables for drilling with replaceable frontal bones pieces for multi-use purposes. An agar gel filled with water was designed to simulate tactile passage through the cortex and into the ventricles. Neurosurgical and emergency resident physicians participated in a didactic session and then attempted placement of an EVD using the model to gauge the simulated model for accuracy and realism. Positioning, procedural time, and realism was evaluated. Improvements in procedural time and positioning were identified for both neurosurgical and emergency medicine (EM) residents. Catheter placement was within ideal position for all participants by the third attempt. All residents stated they felt more comfortable with placement with subsequent attempts. Neurosurgical residents subjectively noted similarities in tactile feedback during drilling compared to in-vivo. A low-cost realistic 3D printed model simulating basic neurosurgical procedures demonstrated improved procedural times and precision with neurosurgical and EM residents. Further, similarities between in-vivo tactile feedback and the low-cost simulation technology was noted. This low cost-model may be used as an adjunct for teaching to promote early procedural competency in neurosurgical techniques to promote learning without predisposition to patient morbidity.

UNASSIGNED: Ideal surgical positioning and placement of implants during arthroplasty are crucial for long-term survival and optimal functional outcomes. Inadequate bone stock or defects, and anatomical variations can influence the outcomes. Three-dimensional printing (3DP) is an evolving technology that could provide patient-specific instrumentation and implants for arthroplasty, taking into account anatomical variations and defects. However, its application in this field is still not adequately studied and described. The present review was conceptualised to assess the practicality, the pros and cons and the current status of usage of 3DP in the field of hip and knee arthroplasties and joint reconstruction surgeries.
UNASSIGNED: A PubMed database search was conducted and a total number of 135 hits were obtained, out of which only 30 articles were relevant. These 30 studies were assessed to obtain the qualitative evidence of the applicability and the current status of 3D printing in arthroplasty.
UNASSIGNED: Currently, 3DP is used for preoperative planning with 3D models, to assess bone defects and anatomy, to determine the appropriate cuts and to develop patient-specific instrumentation and implants (cages, liners, tibial base plates, femoral stem). Its models can be used for teaching and training young surgeons, as well as patient education regarding the surgical complexities. The outcomes of using customised instrumentations and implants have been promising and 3D printing can evolve into routine practice in the years to come.
UNASSIGNED: 3D printing in arthroplasty is an evolving field with promising results; however, current evidence is insufficient to determine significant advantages that can be termed cost effective and readily available.

BACKGROUND: The complex anatomy of the head and neck creates a formidable challenge for surgical reconstruction. However, good functional reconstruction plays a vital role in the quality of life of patients undergoing head and neck surgery. Precision medical treatment in the field of head and neck surgery can greatly improve the prognosis of patients with head and neck tumors. In order to achieve better shape and function, a variety of modern techniques have been introduced to improve the restoration and reconstruction of head and neck surgical defects. Digital surgical technology has great potential applications in the clinical treatment of head and neck cancer because of its advantages of personalization and accuracy.
METHODS: Our department has identified the value of modern digital surgical techniques in the field of head and neck surgery and has explored its utility, including CAD/CAM technology and VR technology. We have achieved good results in the reconstruction of head and neck surgical resection defects.
CONCLUSIONS: In this article, we share five typical cases from the department of head and neck surgery where the reconstruction was performed with the assistance of digital surgical technology.

Residual sensorimotor deficits are common following stroke. While it has been demonstrated that targeted practice can result in improvements in functional mobility years post stroke, there is little to support rehabilitation across the lifespan. The use of technology in home rehabilitation provides an avenue to better support self-management of recovery across the lifespan. We developed a novel mobile technology, capable of quantifying quality of movement with the purpose of providing feedback to augment rehabilitation and improve functional mobility. This mobile rehabilitation system, mRehab, consists of a smartphone embedded in three dimensional printed items representing functional objects found in the home. mRehab allows individuals with motor deficits to practice activities of daily living (ADLs) and receive feedback on their performance. The aim of this study was to assess the usability and consistency of measurement of the mRehab system.
To assess usability of the mRehab system, four older adults and four individuals with stroke were recruited to use the system, and complete surveys to discuss their opinions on the user interface of the smartphone app and the design of the 3D printed items. To assess the consistency of measurement by the mRehab system, 12 young adults were recruited and performed mRehab ADLs in three lab sessions within 1 week. Young adults were chosen for their expected high level of consistency in motor performance.
Usability ratings from older adults and individuals with stroke led us to modify the design of the 3D printed items and improve the clarity of the mRehab app. The modified mRehab system was assessed for consistency of measurement and six ADLs resulted in coefficient of variation (CV) below 10%. This is a commonly used CV goal for consistency. Two ADLs ranged between 10 and 15% CV. Only two ADLs demonstrated high CV.
mRehab is a client-centered technology designed for home rehabilitation that consistently measures performance. Development of the mRehab system provides a support for individuals working on recovering functional upper limb mobility that they can use across their lifespan.

OBJECTIVE: This study aims to determine the effect of auricular scaffold microarchitecture on chondrogenic potential in an in vivo animal model.
METHODS: DICOM computed tomography (CT) images of a human auricle were segmented to create an external anatomic envelope. Image-based design was used to generate 1) orthogonally interconnected spherical pores and 2) randomly interspersed pores, and each were repeated in three dimensions to fill the external auricular envelope. These auricular scaffolds were then 3D printed by laser sintering poly-l-caprolactone, seeded with primary porcine auricular chondrocytes in a hyaluronic acid/collagen hydrogel and cultured in a pro-chondrogenic medium. The auricular scaffolds were then implanted subcutaneously in rats and explanted after 4 weeks for analysis with Safranin O and Hematoxylin and Eosin staining.
RESULTS: Auricular constructs with two micropore architectures were rapidly manufactured with high fidelity anatomic appearance. Subcutaneous implantation of the scaffolds resulted in excellent external appearance of both anterior and posterior auricular surfaces. Analysis on explantation showed that the defined, spherical micropore architecture yielded histologic evidence of more robust chondrogenic tissue formation as demonstrated by Safranin O and Hematoxylin and Eosin staining.
CONCLUSIONS: Image-based computer-aided design and 3D printing offers an exciting new avenue for the tissue-engineered auricle. In early pilot work, creation of spherical micropores within the scaffold architecture appears to impart greater chondrogenicity of the bioscaffold. This advantage could be related to differences in permeability allowing greater cell migration and nutrient flow, differences in surface area allowing different cell aggregation, or a combination of both factors. The ability to design an anatomically correct scaffold that maintains its structural integrity while also promoting auricular cartilage growth represents an important step towards clinical applicability of this new technology.

Three dimensional (3D) printing is a novel technique that has evolved over the past 35 years and has the potential to revolutionize the field of medicine with its inherent advantages of customizability and the ability to create complex shapes with precision. It has been used extensively within the fields of orthopedics, dentistry, and craniofacial reconstruction with wide ranging utility including, medical modeling, surgical planning and the production of custom plates, screws and surgical guides. Furthermore, it has been used for similar means in the field of Otorhinolaryngology and also has potential to revolutionize the treatment of airway malacia. In fact, 3D printed external tracheal splints have already been studied in several pediatric patients with very promising results. The emerging field of 3D bioprinting, which integrates tissue engineering with 3D printing, may produce a paradigm shift with the potential introduction of customized functional biologic replacements.