articles+ search results

Animals, Cats, Dielectric Spectroscopy, Electric Stimulation, Equipment Design, Female, Ink, Male, Neuromuscular Monitoring instrumentation, Rats, Wistar, Sciatic Nerve physiology, Spinal Cord physiology, Urinary Bladder physiology, Zebrafish, Biocompatible Materials, Neuromuscular Monitoring methods, Printing, Three-Dimensional, and Prostheses and Implants

Neuromuscular interfaces are required to translate bioelectronic technologies for application in clinical medicine. Here, by leveraging the robotically controlled ink-jet deposition of low-viscosity conductive inks, extrusion of insulating silicone pastes and in situ activation of electrode surfaces via cold-air plasma, we show that soft biocompatible materials can be rapidly printed for the on-demand prototyping of customized electrode arrays well adjusted to specific anatomical environments, functions and experimental models. We also show, with the monitoring and activation of neuronal pathways in the brain, spinal cord and neuromuscular system of cats, rats and zebrafish, that the printed bioelectronic interfaces allow for long-term integration and functional stability. This technology might enable personalized bioelectronics for neuroprosthetic applications.

Electric Conductivity, Time Factors, Equipment Design methods, Printing, Three-Dimensional, and Radiometry instrumentation

Purpose: To explore 3D printing for rapid development of prototype thin slab low-Z/density ionization chamber arrays viable for custom needs in radiotherapy dosimetry and quality assurance (QA).
Materials and Methods: We designed and fabricated parallel plate ionization chambers and ionization chamber arrays using an off-the-shelf 3D printing equipment. Conductive components of the detectors were made of conductive polylactic acid (cPLA) and insulating components were made of acrylonitrile butadiene styrene (ABS). We characterized the detector responses using a Varian TrueBeam linac at 95 cm SSD in slab solid water phantom at 5 cm depth. We measured the current-voltage (IV) curves, the response to different energy beam lines (2.5 MV, 6 MV, 6 MV FFF) for various dose rates and compared them to responses of a commercial Exradin A12 ionization chamber. We measured off-axis ratio (OAR) for several small field static multi-leaf collimators field sizes (0.5-3 cm) and compared them to OAR data obtained for commissioning of stereotactic radiotherapy.
Results: We identified the printing capability and the limitations of a low-cost off-the-shelf 3D printer for rapid prototyping of detector arrays. The design of the array with sub-millimeter size features conformed to the 3D printing capabilities. IV-curve for the array showed a strong polarity effect (8%) due to the design. Results for the parallel plate and the array compared well with A12 chamber: monitor unit (MU) dependence for the array was within a few % and the response to different energy beam lines was within 1%. Off-axis dose profiles measured with the array were comparable to dose profiles obtained in water tank and stereotactic diode after accounting for the size of the chambers. Dose error was within 2% at the center of the profile and slightly larger at the penumbra.
Conclusions: Rapid prototyping of ion chambers by means of low-cost 3D printing is feasible with certain limitations in the design and spatial accuracy of the printed details.
(© 2019 American Association of Physicists in Medicine.)

Adhesives chemistry, Biocompatible Materials chemistry, Computer Simulation, Dimethylpolysiloxanes chemistry, Endothelial Cells drug effects, Equipment Design, Human Umbilical Vein Endothelial Cells, Humans, Materials Testing, Microtechnology, Oxygen chemistry, Permeability, Polymers, Stress, Mechanical, Tensile Strength, Lab-On-A-Chip Devices, Microfluidics instrumentation, and Printing, Three-Dimensional instrumentation

In the advent of affordable photo- and soft-lithography using polydimethylsiloxane (PDMS), low cost multi-step microfabrication methods have become available to a broad scientific community today. Although these methods are frequently applied for microfluidic prototype production in academic and industrial settings, fast design iterations and rapid prototyping within a few minutes with a high degree of flexibility are nearly impossible. To reduce microfluidic concept-to-chip time and costs, a number of alternative rapid prototyping techniques have recently been introduced including CNC micromachining, 3D printing and plotting out of numeric CAD designs as well as micro-structuring of thin PDMS sheets and pressure sensitive adhesives. Although micro-structuring of pressure sensitive adhesives promises high design flexibility, rapid fabrication and simple biochip assembly, most adhesives are toxic for living biological systems. Since an appropriate bio-interface and proper biology-material interaction is key for any cell chip and organ-on-a-chip system, only a limited number of medical-grade materials are available for microfluidic prototyping. In this study, we have characterized four functional biomedical-grade pressure sensitive adhesives for rapid prototyping (e.g. less than 1 hour) applications including structuring precision, physical and optical properties as well as biocompatibilities. While similar biocompatibility was found for all four adhesives, significant differences in cutting behavior, bonding strength to glass and polymers as well as gas permeability was observed. Practical applications included stability testing of multilayered, membrane-integrated organ-on-a-chip devices under standard cell culture conditions (e.g. 2-3 weeks at 37 °C and 100% humidity) and a shear-impact up to 5 dynes/cm 2 . Additionally, time- and shear-dependent uptake of non-toxic fluorescently labelled nanoparticles on human endothelial cells are demonstrated using micro-structured adhesive-bonded devices. Our results show that (a) both simple and complex microdevices can be designed, fabricated and tested in less than 1 hour, (b) these microdevices are stable for weeks even under physiological shear force conditions and (c) can be used to maintain cell monolayers as well as 3D cell culture systems.

Aged, 80 and over, Blepharoptosis economics, Female, Humans, Retrospective Studies, Blepharoptosis therapy, Equipment Design, Eyelids, Ophthalmology instrumentation, Printing, Three-Dimensional, and Prostheses and Implants economics

Blepharoptosis or ptosis is a common and potentially debilitating clinical problem. Long-term surgical treatment for ptosis caused by progressive myopathies can be challenging due to potential recurrence and complications associated with facial muscle weakness. When surgical treatment is no longer effective, an eyelid crutch can be used as an alternative intervention. This report demonstrates how 3D printing was used to rapidly design, prototype, and manufacture new custom-fit eyelid crutches at a low cost.

Aged, Aged, 80 and over, Calcinosis diagnostic imaging, Calcinosis physiopathology, Cardiac Catheterization adverse effects, Cardiac Catheterization instrumentation, Feasibility Studies, Female, Heart Valve Diseases diagnostic imaging, Heart Valve Diseases physiopathology, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation instrumentation, Humans, Male, Middle Aged, Mitral Valve diagnostic imaging, Mitral Valve physiopathology, Models, Anatomic, Models, Cardiovascular, Postoperative Complications etiology, Severity of Illness Index, Tomography, X-Ray Computed, Treatment Outcome, Calcinosis surgery, Cardiac Catheterization methods, Heart Valve Diseases surgery, Heart Valve Prosthesis Implantation methods, Mitral Valve surgery, Patient-Specific Modeling, and Printing, Three-Dimensional

Introduction: Three-dimensional (3D) prototyping is a novel technology which can be used to plan and guide complex procedures such as transcatheter mitral valve replacement (TMVR).
Methods: Eight patients with severe mitral annular calcification (MAC) underwent TMVR. 3D digital models with digital balloon expandable valves were created from pre-procedure CT scans using dedicated software. Five models were printed. These models were used to assess prosthesis sizing, anchoring, expansion, paravalvular gaps, left ventricular outflow tract (LVOT) obstruction, and other potential procedure pitfalls. Results of 3D prototyping were then compared to post procedural imaging to determine how closely the achieved procedural result mirrored the 3D modeled result.
Results: 3D prototyping simulated LVOT obstruction in one patient who developed it and in another patient who underwent alcohol septal ablation prior to TMVR. Valve sizing correlated with actual placed valve size in six out of the eight patients and more than mild paravalvular leak (PVL) was simulated in two of the three patients who had it. Patients who had mismatch between their modeled valve size and post-procedural imaging were the ones that had anterior leaflet resection which could have altered valve sizing and PVL simulation. 3D printed model of one of the latter patients allowed modification of anterior leaflet to simulate surgical resection and was able to estimate the size and location of the PVL after inserting a valve stent into the physical model.
Conclusion: 3D prototyping in TMVR for severe MAC is feasible for simulating valve sizing, apposition, expansion, PVL, and LVOT obstruction.
(© 2018 Wiley Periodicals, Inc.)

Adolescent, Cone-Beam Computed Tomography, Dental Models, Female, Humans, Mandible, Osteotomy, Tooth Socket surgery, Transplantation, Autologous, Computer Simulation, Computer-Aided Design, Dental Implantation methods, Dental Implants, Molar, Third transplantation, Printing, Three-Dimensional, Surgery, Computer-Assisted methods, and User-Computer Interface

This case report describes an innovative virtual simulation method using a computer-aided rapid prototyping (CARP) model and a computer-aided design (CAD) program for autotransplantation of an immature third molar.A compromised left mandibular second molar (#18) was extracted and replaced by autotransplantation using an immature left mandibular third molar (#17). In order to minimize the surgical time and injury to the donor tooth, a virtual 3-dimensional (3D) rehearsal surgery was planned. Cone-beam computed tomographic images were taken to fabricate the 3D printing CARP model of the donor tooth and tentative extraction socket. Subsequently, both CARP models were scanned with an intraoral scanner (CEREC Omnicam; Dentsply Sirona, Bensheim, Germany) followed by superimposition and virtual simulation of osteotomy preparation of the recipient alveolus using the CAD analysis program. During the surgery, the extraction socket was precisely prepared according to the predetermined location and dimensions via virtual simulation rehearsal surgery using CAD analysis. The donor tooth was atraumatically transplanted into the prepared socket. The follow-up examination revealed that the root developed with a normal periodontal ligament and lamina dura.Virtual simulation using a 3D printing CARP model and a CAD program could be clinically useful in autotransplantation of an immature third molar by ensuring an atraumatic and predictable surgery.
(Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Adult, Aortic Aneurysm, Thoracic diagnostic imaging, Aortic Aneurysm, Thoracic physiopathology, Aortic Coarctation diagnostic imaging, Aortic Coarctation physiopathology, Aortography, Computed Tomography Angiography, Feasibility Studies, Female, Hemodynamics, Humans, Treatment Outcome, Workflow, Aortic Aneurysm, Thoracic surgery, Aortic Coarctation surgery, Endovascular Procedures instrumentation, Models, Anatomic, Models, Cardiovascular, Printing, Three-Dimensional, and Vascular Grafting

Equipment Design, Metals, Polymers, Reference Standards, Time Factors, Bone Screws, Materials Testing standards, Mechanical Phenomena, Orthopedic Procedures instrumentation, and Printing, Three-Dimensional

The majority of orthopaedic screws are designed, tested and manufactured by existing orthopaedics companies and are predominantly developed with healthy bone in mind. The timescales and costs involved in the development of a new screw design, for example, for osteoporotic bone, are high. In this study, standard wood screws were used to analyse the concept of using three-dimensional printing, or rapid prototyping, as a viable stage of development in the design of a new bone screw. Six wood screws were reverse engineered and printed in polymeric material using stereolithography. Three of the designs were also printed in Ti6Al4V using direct metal laser sintering; however, these were not of sufficient quality to test further. Both the original metal screws (metal) and polymeric rapid prototyping screws were then tested using standard pull-out tests from low-density polyurethane blocks (Sawbones). Results showed the highest pull-out strengths for screws with the longest thread length and the smallest inner diameter. Of the six screw designs tested, five showed no more than a 17% variance between the metal and rapid prototyping results. A similar pattern of results was shown between the screw designs for both the metal and rapid prototyping screws in five of the six cases. While not producing fully comparable pull-out results to orthopaedic screws, the results from this study do provide evidence of the potential usefulness and cost-effectiveness of rapid prototyping in the early stages of design and testing of orthopaedic screws.

Drug Liberation, Porosity, Tablets pharmacokinetics, Printing, Three-Dimensional, Tablets chemistry, and Technology, Pharmaceutical methods

The problem of designing tablet geometry and its internal structure that results into a specified release profile of the drug during dissolution was considered. A solution method based on parametric programming, inspired by CAD (computer-aided design) approaches currently used in other fields of engineering, was proposed and demonstrated. The solution of the forward problem using a parametric series of structural motifs was first carried out in order to generate a library of drug release profiles associated with each structural motif. The inverse problem was then solved in three steps: first, the combination of basic structural motifs whose superposition provides the closest approximation of the required drug release profile was found by a linear combination of pre-calculated release profiles. In the next step, the final tablet design was constructed and its dissolution curve found computationally. Finally, the proposed design was 3D printed and its dissolution profile was confirmed experimentally. The computational method was based on the numerical solution of drug diffusion in a boundary layer surrounding the tablet, coupled with erosion of the tablet structure encoded by the phase volume function. The tablets were 3D printed by fused deposition modelling (FDM) from filaments produced by hot-melt extrusion. It was found that the drug release profile could be effectively controlled by modifying the tablet porosity. Custom release profiles were obtained by combining multiple porosity regions in the same tablet. The computational method yielded accurate predictions of the drug release rate for both single- and multi-porosity tablets.

Drug Compounding methods, Excipients, Powders, Spectroscopy, Near-Infrared methods, Time Factors, Acetaminophen chemistry, Chemistry, Pharmaceutical methods, and Printing, Three-Dimensional statistics numerical data

There is an increasing need to provide more detailed insight into the behavior of particulate systems. The current powder characterization tools are developed empirically and in many cases, modification of existing equipment is difficult. More flexible tools are needed to provide understanding of complex powder behavior, such as mixing process and segregation phenomenon. An approach based on the fast prototyping of new powder handling geometries and interfacing solutions for process analytical tools is reported. This study utilized 3D printing for rapid prototyping of customized geometries; overall goal was to assess mixing process of powder blends at small-scale with a combination of spectroscopic and mechanical monitoring. As part of the segregation evaluation studies, the flowability of three different paracetamol/filler-blends at different ratios was investigated, inter alia to define the percolation thresholds. Blends with a paracetamol wt% above the percolation threshold were subsequently investigated in relation to their segregation behavior. Rapid prototyping using 3D printing allowed designing two funnels with tailored flow behavior (funnel flow) of model formulations, which could be monitored with an in-line near-infrared (NIR) spectrometer. Calculating the root mean square (RMS) of the scores of the two first principal components of the NIR spectra visualized spectral variation as a function of process time. In a same setup, mechanical properties (basic flow energy) of the powder blend were monitored during blending. Rapid prototyping allowed for fast modification of powder testing geometries and easy interfacing with process analytical tools, opening new possibilities for more detailed powder characterization.

Alginates, Hydrogels, Tissue Culture Techniques, Biocompatible Materials, Extracellular Matrix, and Printing, Three-Dimensional

This paper presents a fabrication method for rapid prototyping of 3D biomaterial constructs with vascular structures. The method relies on poloxamer fugitive ink, which is over casted with a custom-made alginate based model extracellular matrix (ECM). The presented method is simple to implement and compatible with standard cell culture workflows used in biomedical research and pharmaceutical development. We present the material preparation, gelation properties and printing methods in detail. First experiments demonstrate the suitability of the ECM constructs for 3D tissue culture.

Adult, Female, Humans, Male, Middle Aged, Models, Anatomic, Prospective Studies, Education, Medical, Graduate, Kidney anatomy histology, Kidney surgery, Nephrectomy education, and Printing, Three-Dimensional

Background: Three-dimensional (3D) printing has been introduced as a novel technique to produce 3D objects. We tried to evaluate the clinical usefulness of 3D-printed renal model in performing partial nephrectomy (PN) and also in the education of medical students.
Materials and Methods: We prospectively produced personalized renal models using 3D-printing methods from preoperative computed tomography (CT) images in a total of 10 patients. Two different groups (urologist and student group) appraised the clinical usefulness of 3D-renal models by answering questionnaires.
Results: After application of 3D renal models, the urologist group gave highly positive responses in asking clinical usefulness of 3D-model among PN (understanding personal anatomy: 8.9 / 10, preoperative surgical planning: 8.2 / 10, intraoperative tumor localization: 8.4 / 10, plan for further utilization in future: 8.3 / 10, clinical usefulness in complete endophytic mass: 9.5 / 10). The student group located each renal tumor correctly in 47.3% when they solely interpreted the CT images. After the introduction of 3D-models, the rate of correct answers was significantly elevated to 70.0% (p < 0.001). The subjective difficulty level in localizing renal tumor was also significantly low (52% versus 27%, p < 0.001) when they utilized 3D-models.
Conclusion: The personalized 3D renal model was revealed to significantly enhance the understanding of correct renal anatomy in patients with renal tumors in both urologist and student groups. These models can be useful for establishing the perioperative planning and also education program for medical students.
(Copyright® by the International Brazilian Journal of Urology.)

Alloys, Computer-Aided Design, Finite Element Analysis, Humans, Male, Middle Aged, Prosthesis Implantation, Reconstructive Surgical Procedures methods, Thoracic Wall surgery, Titanium, Tomography, X-Ray Computed, Printing, Three-Dimensional, Prosthesis Design methods, Reconstructive Surgical Procedures instrumentation, Ribs surgery, Sternum surgery, and Thoracic Neoplasms surgery

Background: As 3D printing technology emerge, there is increasing demand for a more customizable implant in the repair of chest-wall bony defects. This article aims to present a custom design and fabrication method for repairing bony defects of the chest wall following tumour resection, which utilizes three-dimensional (3D) printing and rapid-prototyping technology.
Methods: A 3D model of the bony defect was generated after acquiring helical CT data. A customized prosthesis was then designed using computer-aided design (CAD) and mirroring technology, and fabricated using titanium-alloy powder. The mechanical properties of the printed prosthesis were investigated using ANSYS software.
Results: The yield strength of the titanium-alloy prosthesis was 950 ± 14 MPa (mean ± SD), and its ultimate strength was 1005 ± 26 MPa. The 3D finite element analyses revealed that the equivalent stress distribution of each prosthesis was unifrom. The symmetry and reconstruction quality contour of the repaired chest wall was satisfactory. No rejection or infection occurred during the 6-month follow-up period.
Conclusion: Chest-wall reconstruction with a customized titanium-alloy prosthesis is a reliable technique for repairing bony defects.

Adult, Aged, Aged, 80 and over, Brain Abscess diagnostic imaging, Brain Abscess surgery, Brain Diseases diagnostic imaging, Brain Neoplasms diagnostic imaging, Brain Neoplasms secondary, Brain Neoplasms surgery, Computed Tomography Angiography, Craniopharyngioma diagnostic imaging, Craniopharyngioma surgery, Female, Germinoma diagnostic imaging, Germinoma surgery, Glioma diagnostic imaging, Glioma surgery, Hemangioblastoma diagnostic imaging, Hemangioblastoma surgery, Humans, Imaging, Three-Dimensional, Intracranial Arteriovenous Malformations diagnostic imaging, Intracranial Arteriovenous Malformations surgery, Lymphoma diagnostic imaging, Lymphoma surgery, Magnetic Resonance Imaging, Male, Meningeal Neoplasms diagnostic imaging, Meningioma diagnostic imaging, Middle Aged, Models, Anatomic, Neuroma, Acoustic diagnostic imaging, Neuroma, Acoustic surgery, Neurosurgical Procedures education, Optic Nerve anatomy histology, Orbit, Organ Size, Pituitary Neoplasms diagnostic imaging, Pituitary Neoplasms surgery, Reproducibility of Results, Simulation Training, Sphenoid Bone diagnostic imaging, Tomography, X-Ray Computed, Vertebral Artery Dissection diagnostic imaging, Vertebral Artery Dissection surgery, Brain Diseases surgery, Meningeal Neoplasms surgery, Meningioma surgery, Neurosurgical Procedures methods, Optic Nerve diagnostic imaging, Printing, Three-Dimensional, and Sphenoid Bone surgery

Background: As the anatomical three-dimensional (3D) positional relationship around the anterior clinoid process (ACP) is complex, experience of many surgeries is necessary to understand anterior clinoidectomy (AC). We prepared a 3D synthetic image from computed tomographic angiography (CTA) and magnetic resonance imaging (MRI) data and a rapid prototyping (RP) model from the imaging data using a 3D printer. The objective of this study was to evaluate anatomical reproduction of the 3D synthetic image and intraosseous region after AC in the RP model. In addition, the usefulness of the RP model for operative simulation was investigated.
Methods: The subjects were 51 patients who were examined by CTA and MRI before surgery. The size of the ACP, thickness and length of the optic nerve and artery, and intraosseous length after AC were measured in the 3D synthetic image and RP model, and reproducibility in the RP model was evaluated. In addition, 10 neurosurgeons performed AC in the completed RP models to investigate their usefulness for operative simulation.
Results: The RP model reproduced the region in the vicinity of the ACP in the 3D synthetic image, including the intraosseous region, at a high accuracy. In addition, drilling of the RP model was a useful operative simulation method of AC.
Conclusions: The RP model of the vicinity of ACP, prepared using a 3D printer, showed favorable anatomical reproducibility, including reproduction of the intraosseous region. In addition, it was concluded that this RP model is useful as a surgical education tool for drilling.

Adolescent, Bicuspid injuries, Bicuspid surgery, Dental Prosthesis Design, Female, Humans, Mandibular Fractures surgery, Molar injuries, Molar surgery, Radiography, Panoramic, Root Canal Therapy, Tooth Socket surgery, Transplantation, Autologous, Cone-Beam Computed Tomography, Dental Implants, Molar, Third diagnostic imaging, Molar, Third transplantation, and Printing, Three-Dimensional

This article describes the autotransplantation of third molars to replace heavily damaged premolars and molars. Specifically, this article reports on the use of preoperative cone-beam computed tomographic planning and 3-dimensional (3D) printed replicas of donor teeth to prepare artificial tooth sockets. In the present case, an 18-year-old patient underwent autotransplantation of 3 third molars to replace 1 premolar and 2 molars that were heavily damaged after trauma. Approximately 1 year after the traumatic incident, autotransplantation with the help of 3D planning and rapid prototyping was performed. The right maxillary third molar replaced the right maxillary first premolar. The 2 mandibular wisdom teeth replaced the left mandibular first and second molars. During the surgical procedure, artificial tooth sockets were prepared with the help of 3D printed donor tooth copies to prevent iatrogenic damage to the actual donor teeth. These replicas of the donor teeth were designed based on the preoperative cone-beam computed tomogram and manufactured with the help of 3D printing techniques. The use of a replica of the donor tooth resulted in a predictable and straightforward procedure, with extra-alveolar times shorter than 2 minutes for all transplantations. The transplanted teeth were placed in infraocclusion and fixed with a suture splint. Postoperative follow-up showed physiologic integration of the transplanted teeth and a successful outcome for all transplants. In conclusion, this technique facilitates a straightforward and predictable procedure for autotransplantation of third molars. The use of printed analogues of the donor teeth decreases the risk of iatrogenic damage and the extra-alveolar time of the transplanted tooth is minimized. This facilitates a successful outcome.
(Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Computer-Aided Design, Humans, Imaging, Three-Dimensional, Reproducibility of Results, Dental Impression Technique, Denture, Complete, and Printing, Three-Dimensional

Objective: To assess the trueness and precision of copy denture templates produced using traditional methods and 3D printing.
Material and Methods: Six copies of a denture were made using: 1. Conventional technique with silicone putty in an impression tray (CT). 2. Conventional technique with no impression tray (CNT). 3. 3D scanning and printing (3D). Scan trueness and precision was investigated by scanning a denture six times and comparing five scans to the sixth. Then the scans of the six CT, CNT and 3D dentures were compared by aligning, in turn, the copies of each denture to the scanned original. Outcome measures were the mean surface-to-surface distance, standard deviation of that distance and the maximum distance. Student's unpaired t-tests with Bonferroni correction were used to analyse the results.
Results: The repeated scans of the original denture showed a scan trueness of 0.013mm (SD 0.002) and precision of 0.013mm (SD 0.002). Trueness: CT templates, 0.168mm (0.047), CNT templates 0.195mm (0.034) and 3D 0.103mm (0.021). Precision: CT templates 0.158mm (0.037), CNT 0.233mm (0.073), 3D 0.090mm (0.017). For each outcome measure the 3D templates demonstrated an improvement which was statistically significant (p⟨0.05).
Conclusions: 3D printed copy denture templates reproduced the original with greater trueness and precision than conventional techniques.
(Copyright© 2017 Dennis Barber Ltd.)

Animals, Humans, Biocompatible Materials chemistry, Biocompatible Materials therapeutic use, Printing, Three-Dimensional, Prosthesis Design methods, and Tissue Scaffolds chemistry

Over the past decades, solid freeform fabrication (SFF) has emerged as the main technology for the production of scaffolds for tissue engineering applications as a result of the architectural versatility. However, certain limitations have also arisen, primarily associated with the available, rather limited range of materials suitable for processing. To overcome these limitations, several research groups have been exploring novel methodologies through which a construct, generated via SFF, is applied as a sacrificial mould for production of the final construct. The technique combines the benefits of SFF techniques in terms of controlled, patient-specific design with a large freedom in material selection associated with conventional scaffold production techniques. Consequently, well-defined 3D scaffolds can be generated in a straightforward manner from previously difficult to print and even "unprintable" materials due to thermomechanical properties that do not match the often strict temperature and pressure requirements for direct rapid prototyping. These include several biomaterials, thermally degradable materials, ceramics and composites. Since it can be combined with conventional pore forming techniques, indirect rapid prototyping (iRP) enables the creation of a hierarchical porosity in the final scaffold with micropores inside the struts. Consequently, scaffolds and implants for applications in both soft and hard tissue regeneration have been reported. In this review, an overview of different iRP strategies and materials are presented from the first reports of the approach at the turn of the century until now.

Aged, Automation, Breast Neoplasms pathology, Female, Humans, Image Interpretation, Computer-Assisted methods, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging methods, Mammography methods, Middle Aged, Radiographic Image Enhancement methods, Ultrasonography methods, Breast Neoplasms diagnostic imaging, Models, Anatomic, and Printing, Three-Dimensional

Objective: Three-dimensional (3D) printing has become widely available, and a few cases of its use in clinical practice have been described. The aim of this study was to explore facilities for the semi-automated delineation of breast cancer tumors and to assess the feasibility of 3D printing of breast cancer tumors.
Methods: In a case series of five patients, different 3D imaging methods-magnetic resonance imaging (MRI), digital breast tomosynthesis (DBT), and 3D ultrasound-were used to capture 3D data for breast cancer tumors. The volumes of the breast tumors were calculated to assess the comparability of the breast tumor models, and the MRI information was used to render models on a commercially available 3D printer to materialize the tumors.
Results: The tumor volumes calculated from the different 3D methods appeared to be comparable. Tumor models with volumes between 325 mm 3 and 7,770 mm 3 were printed and compared with the models rendered from MRI. The materialization of the tumors reflected the computer models of them.
Conclusion: 3D printing (rapid prototyping) appears to be feasible. Scenarios for the clinical use of the technology might include presenting the model to the surgeon to provide a better understanding of the tumor's spatial characteristics in the breast, in order to improve decision-making in relation to neoadjuvant chemotherapy or surgical approaches. J. Surg. Oncol. 2017;115:238-242. © 2016 Wiley Periodicals, Inc.
(© 2016 Wiley Periodicals, Inc.)

Humans, Severity of Illness Index, Dental Models, Malocclusion pathology, and Printing, Three-Dimensional

Introduction: Rapid prototyping models can be reconstructed from stereolithographic digital study model data to produce hard-copy casts. In this study, we aimed to compare agreement and accuracy of measurements made with rapid prototyping and stone models for different degrees of crowding.
Methods: The Z Printer 450 (3D Systems, Rock Hill, SC) reprinted 10 sets of models for each category of crowding (mild, moderate, and severe) scanned using a structured-light scanner (Maestro 3D, AGE Solutions, Pisa, Italy). Stone and RP models were measured using digital calipers for tooth sizes in the mesiodistal, buccolingual, and crown height planes and for arch dimension measurements. Bland-Altman and paired t test analyses were used to assess agreement and accuracy. Clinical significance was set at ±0.50 mm.
Results: Bland-Altman analysis showed the mean bias of measurements between the models to be within ±0.15 mm (SD, ±0.40 mm), but the 95% limits of agreement exceeded the cutoff point of ±0.50 mm (lower range, -0.81 to -0.41 mm; upper range, 0.34 to 0.76 mm). Paired t tests showed statistically significant differences for all planes in all categories of crowding except for crown height in the moderate crowding group and arch dimensions in the mild and moderate crowding groups.
Conclusions: The rapid prototyping models were not clinically comparable with conventional stone models regardless of the degree of crowding.
(Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Adult, Alveolar Bone Loss diagnostic imaging, Bone Transplantation methods, Cone-Beam Computed Tomography, Crowns, Cuspid diagnostic imaging, Cuspid surgery, Gingival Recession diagnostic imaging, Humans, Male, Tooth Extraction, Tooth Socket diagnostic imaging, Alveolar Bone Loss surgery, Computer-Aided Design, Dental Implants, Single-Tooth, Gingival Recession surgery, Immediate Dental Implant Loading, Printing, Three-Dimensional, and Tooth Socket surgery

Purpose: This article describes the use of rapid prototyping (RP) for diagnosis, planning, and execution of the reconstruction of hard and soft tissue in socket defects using immediate dentoalveolar restoration (IDR).
Summary: In cases of tissue loss in anterior dental areas, esthetic rehabilitation poses a major challenge with respect to treatment planning with the goal of long-term tissue maintenance. The IDR technique consists of immediate reconstruction in a single procedure of bone and soft tissue around implants placed immediately after extraction, and prosthetic rehabilitation. As this procedure is immediate and flapless, the correct diagnosis of tissue loss and correct graft adaptation are mandatory. RP can increase the precision of the procedure, as demonstrated using a clinical case characterized by total loss of the buccal bone wall and gingival recession. The results were evaluated by clinical assessment, photography, radiography, cone beam computed tomography (CBCT), and prototyping.
Conclusion: The application of RP facilitated the execution of IDR as it enabled more accurate diagnosis of the socket defect and more precise adaptation of the tissue graft. A clinical study should be conducted to evaluate the effects of RP on the clinical results of the IDR technique.