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Journal of Esthetic and Restorative... Jul 2022To characterize the mechanical and biological properties of three commercially available resins, which are currently used for provisional restorations and to compare...
OBJECTIVES
To characterize the mechanical and biological properties of three commercially available resins, which are currently used for provisional restorations and to compare them to an experimental resin intended for definitive fixed dental prostheses.
MATERIALS AND METHODS
Three commercially available resins: Crowntec (CT, Saremco), Temporary C&B (FL, Formlabs), C&B MFH (ND, Nextdent), and the experimental resin: Permanent Bridge (PB, Saremco) were printed and subjected to biaxial flexural strength test, finite element analysis, Weibull analysis, scanning electron microscopy, cell proliferation, immunohistochemistry and cytotoxicity assays. Samples from CT, PB, and ND were provided directly from the manufacturers ensuring ideal workflow. FL was printed using the workflow as recommended by the manufacturer, using a Formlabs 2 printer and their post-processing units Form Wash and Form Cure.
RESULTS
From the tested resins, PB yielded the best overall results in terms of mechanical properties. Cell proliferation and cytotoxicity did not show any significant differences among materials. PB showed higher values for probability of survival predictions (35%) when subjected to 250 MPa loads, whereas the other materials did not reach 10%.
SIGNIFICANCE
Despite mechanical differences between the evaluated materials, the outcomes suggest that 3D printed provisional resins may be used in clinical settings, following the manufacturers indications. New materials intended for long-term use, such as the PB resin, yielded higher mechanical properties compared to the other materials. Alternative printing and post-processing methods have not yet been evaluated and should be avoided until further literature is available.
CLINICAL SIGNIFICANCE
3D printed resins for provisional restorations have become popular with the emergence of new technologies. In this study, we evaluated three different commercially available resins for provisional restorations and one new experimental resin. The results from this study indicate that commercially available resins could be used in clinical settings under certain conditions and limited periods of time. Following the manufacturers protocols is of paramount importance to not compromise these properties.
Topics: Composite Resins; Flexural Strength; Materials Testing; Printing, Three-Dimensional; Surface Properties
PubMed: 35187786
DOI: 10.1111/jerd.12888 -
Facial Plastic Surgery : FPS May 2004Soft tissue replacement using a filler as a temporary scaffold to encourage revascularization and tissue in growth is an exciting concept. Sheets of acellular human...
Soft tissue replacement using a filler as a temporary scaffold to encourage revascularization and tissue in growth is an exciting concept. Sheets of acellular human dermal matrix, called Alloderm (Lifecell Corp, Branchburg, NJ), have been shown to do just that. When implanted into a patient, tissue growth and revascularization have both been observed. The company manufactures a micronized or injectable form called Cymetra. This article reviews the manufacturing, tissue interaction, clinical applications, and anticipated clinical results.
Topics: Biocompatible Materials; Collagen; Female; Graft Survival; Humans; Injections, Intradermal; Injections, Subcutaneous; Lipodystrophy; Male; Prostheses and Implants; Rhytidoplasty
PubMed: 15643579
DOI: 10.1055/s-2004-861753 -
Frontiers in Psychiatry 2022In 2021, the manufacturer of diamorphine reported a possible impending shortage for Switzerland and Germany. This led us to investigate this controlled medicine's... (Review)
Review
In 2021, the manufacturer of diamorphine reported a possible impending shortage for Switzerland and Germany. This led us to investigate this controlled medicine's manufacture, market, and regulatory constraints. Based on our analysis of legal texts and gray literature in the form of reports and documents, we propose recommendations to prevent and address diamorphine shortages in Switzerland. Diamorphine, also known as pharmaceutical "heroin," is used medically to treat persons with severe opioid use disorder in a handful of countries. The controlled medicine is manufactured from morphine, which, in turn, is extracted from opium poppies. Studying data from the International Narcotics Control Board for 2019, we find that Switzerland accounts for almost half of the worldwide medical consumption of diamorphine. It manufactures more than half of the worldwide total and keeps the largest stocks. Moreover, Switzerland is dependent on a sole supplier of diamorphine (monopoly). As a niche product, diamorphine has an increased risk of shortage. Such a shortage would immediately threaten a valuable public health program for around 1,660 Swiss patients. We believe it is urgent to curtail the monopoly and ensure a stable supply for the future.
PubMed: 35615450
DOI: 10.3389/fpsyt.2022.882299 -
Applied Optics May 2020Tolerancing is an important step toward the fabrication of high-quality and cost-effective lens surfaces. It is critical for wafer-level optics, when up to tens of...
Tolerancing is an important step toward the fabrication of high-quality and cost-effective lens surfaces. It is critical for wafer-level optics, when up to tens of thousands microlenses are fabricated in parallel and whose surfaces cannot be formed individually. However, approaches developed for macro-optics cannot be directly transposed for microlenses because of differences in fabrication and testing techniques. In particular, microlens surfaces are usually limited to conical surfaces. Here, we study the connection between the microlens optical performance and the form of its surface, suggesting surface form representations suited for tolerancing purposes. Then, we compare them with common representations for tolerancing real optical systems. Measured surface forms of microlenses are also provided to make the tolerancing procedure realistic. In addition, we propose term definitions for micro-optics, complements to typical terms for macro-optics, to ease the communication between optical designers and manufacturers. Based on the results presented in this paper, guidelines are proposed for tolerancing microlenses. We suggest applying them as a first step toward a more effective and comprehensive tolerancing procedure.
PubMed: 32400660
DOI: 10.1364/AO.388453 -
Materials (Basel, Switzerland) Aug 2021Nickel-titanium alloys have been widely used in biomedical, aerospace and other fields due to their shape memory effect, superelastic effect, as well as biocompatible... (Review)
Review
Nickel-titanium alloys have been widely used in biomedical, aerospace and other fields due to their shape memory effect, superelastic effect, as well as biocompatible and elasto-thermal properties. Additive manufacturing (AM) technology can form complex and fine structures, which greatly expands the application range of Ni-Ti alloy. In this study, the development trend of additive manufactured Ni-Ti alloy was analyzed. Subsequently, the most widely used selective laser melting (SLM) process for forming Ni-Ti alloy was summarized. Especially, the relationship between Ni-Ti alloy materials, SLM processing parameters, microstructure and properties of Ni-Ti alloy formed by SLM was revealed. The research status of Ni-Ti alloy formed by wire arc additive manufacturing (WAAM), electron beam melting (EBM), directional energy dedication (DED), selective laser sintering (SLS) and other AM processes was briefly described, and its mechanical properties were emphatically expounded. Finally, several suggestions concerning Ni-Ti alloy material preparation, structure design, forming technology and forming equipment in the future were put forward in order to accelerate the engineering application process of additive manufactured Ni-Ti alloy. This study provides a useful reference for scientific research and engineering application of additive manufactured Ni-Ti alloys.
PubMed: 34443019
DOI: 10.3390/ma14164496 -
Annual Review of Biomedical Engineering Jul 2021Additive manufacturing's attributes include print customization, low per-unit cost for small- to mid-batch production, seamless interfacing with mainstream medical 3D... (Review)
Review
Additive manufacturing's attributes include print customization, low per-unit cost for small- to mid-batch production, seamless interfacing with mainstream medical 3D imaging techniques, and feasibility to create free-form objects in materials that are biocompatible and biodegradable. Consequently, additive manufacturing is apposite for a wide range of biomedical applications including custom biocompatible implants that mimic the mechanical response of bone, biodegradable scaffolds with engineered degradation rate, medical surgical tools, and biomedical instrumentation. This review surveys the materials, 3D printing methods and technologies, and biomedical applications of metal 3D printing, providing a historical perspective while focusing on the state of the art. It then identifies a number of exciting directions of future growth: () the improvement of mainstream additive manufacturing methods and associated feedstock; () the exploration of mature, less utilized metal 3D printing techniques; () the optimization of additively manufactured load-bearing structures via artificial intelligence; and () the creation of monolithic, multimaterial, finely featured, multifunctional implants.
Topics: Artificial Intelligence; Humans; Printing, Three-Dimensional; Prostheses and Implants
PubMed: 34255995
DOI: 10.1146/annurev-bioeng-082020-032402 -
The Journal of Pharmacy and Pharmacology Jun 2015This review seeks to offer a broad perspective that encompasses an understanding of the drug product attributes affected by active pharmaceutical ingredient (API)... (Review)
Review
This review seeks to offer a broad perspective that encompasses an understanding of the drug product attributes affected by active pharmaceutical ingredient (API) physical properties, their link to solid form selection and the role of particle engineering. While the crucial role of active pharmaceutical ingredient (API) solid form selection is universally acknowledged in the pharmaceutical industry, the value of increasing effort to understanding the link between solid form, API physical properties and drug product formulation and manufacture is now also being recognised. A truly holistic strategy for drug product development should focus on connecting solid form selection, particle engineering and formulation design to both exploit opportunities to access simpler manufacturing operations and prevent failures. Modelling and predictive tools that assist in establishing these links early in product development are discussed. In addition, the potential for differences between the ingoing API physical properties and those in the final product caused by drug product processing is considered. The focus of this review is on oral solid dosage forms and dry powder inhaler products for lung delivery.
Topics: Chemistry, Pharmaceutical; Crystallization; Dosage Forms; Drug Design; Humans; Pharmaceutical Preparations; Technology, Pharmaceutical
PubMed: 25677227
DOI: 10.1111/jphp.12375 -
Pharmaceutics Sep 2022Nanoparticulate technologies have revolutionized drug delivery allowing for passive and active targeting, altered biodistribution, controlled drug release... (Review)
Review
Nanoparticulate technologies have revolutionized drug delivery allowing for passive and active targeting, altered biodistribution, controlled drug release (temporospatial or triggered), enhanced stability, improved solubilization capacity, and a reduction in dose and adverse effects. However, their manufacture remains immature, and challenges exist on an industrial scale due to high batch-to-batch variability hindering their clinical translation. Lipid-based nanomedicines remain the most widely approved nanomedicines, and their current manufacturing methods remain discontinuous and face several problems such as high batch-to-batch variability affecting the critical quality attributes (CQAs) of the product, laborious multistep processes, need for an expert workforce, and not being easily amenable to industrial scale-up involving typically a complex process control. Several techniques have emerged in recent years for nanomedicine manufacture, but a paradigm shift occurred when microfluidic strategies able to mix fluids in channels with dimensions of tens of micrometers and small volumes of liquid reagents in a highly controlled manner to form nanoparticles with tunable and reproducible structure were employed. In this review, we summarize the recent advancements in the manufacturing of lipid-based nanomedicines using microfluidics with particular emphasis on the parameters that govern the control of CQAs of final nanomedicines. The impact of microfluidic environments on formation dynamics of nanomaterials, and the application of microdevices as platforms for nanomaterial screening are also discussed.
PubMed: 36145688
DOI: 10.3390/pharmaceutics14091940 -
Journal of Pharmaceutical Sciences Mar 2015Pharmaceutical excipients are essential components of most modern dosage forms. Although defined as pharmacologically inert, excipients can be thought of as the true... (Review)
Review
Pharmaceutical excipients are essential components of most modern dosage forms. Although defined as pharmacologically inert, excipients can be thought of as the true enablers of drug product performance. Unintentional variability in the properties of the excipients may be unavoidable, albeit minimizable. The variability may originate from the source, the excipient-manufacturing process, or during the manufacturing of dosage forms. Excipient variability may have a range of influences on their functionality and performance in the dosage form. A better understanding of these influences on the critical quality attributes of the final product is of prime importance. Modern analytical tools provide a significant assistance in characterizing excipient variability to achieve this understanding. The principles and concepts of Quality-by-Design, process analytical technology, and design space, provide a holistic risk-based approach toward manufacture and application of excipients in pharmaceutical formulations. The International Pharmaceutical Excipients Council (IPEC) has developed guidelines for proper selection, use, and evaluation of excipients in pharmaceutical products.
Topics: Chemistry, Pharmaceutical; Dosage Forms; Excipients; Pharmaceutical Preparations; Quality Control; Technology, Pharmaceutical
PubMed: 25561249
DOI: 10.1002/jps.24299 -
Burns & Trauma 2018Material extrusion additive manufacturing has rapidly grown in use for tissue engineering research since its adoption in the year 2000. It has enabled researchers to... (Review)
Review
Material extrusion additive manufacturing has rapidly grown in use for tissue engineering research since its adoption in the year 2000. It has enabled researchers to produce scaffolds with intricate porous geometries that were not feasible with traditional manufacturing processes. Researchers can control the structural geometry through a wide range of customisable printing parameters and design choices including material, print path, temperature, and many other process parameters. Currently, the impact of these choices is not fully understood. This review focuses on how the position and orientation of extruded filaments, which sometimes referred to as the print path, lay-down pattern, or simply "scaffold design", affect scaffold properties and biological performance. By analysing trends across multiple studies, new understanding was developed on how filament position affects mechanical properties. Biological performance was also found to be affected by filament position, but a lack of consensus between studies indicates a need for further research and understanding. In most research studies, scaffold design was dictated by capabilities of additive manufacturing software rather than free-form design of structural geometry optimised for biological requirements. There is scope for much greater application of engineering innovation to additive manufacture novel geometries. To achieve this, better understanding of biological requirements is needed to enable the effective specification of ideal scaffold geometries.
PubMed: 29988731
DOI: 10.1186/s41038-018-0121-4