Direct composite restorations are accepted as a treatment option for microdontia, which is a relatively prevalent condition that poses esthetic concerns. While free-hand composite placement is technique-sensitive and time-consuming, the resin composite injection technique is more straightforward and predictable. A fully digital workflow has been recently introduced, but the 3D-printed resin index is rigid and challenged by undercuts, as opposed to the silicone index. This case report presents a flexible 3D-printed resin index, which can accurately transfer the digitally simulated functional and esthetic form to the final restoration. In addition, a rigid stabilization holder was designed to stabilize the flexible index.
- MeSH
- 3D tisk MeSH
- estetika stomatologická * MeSH
- lidé MeSH
- průběh práce MeSH
- silikony MeSH
- složené pryskyřice * terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
OBJECTIVE: Precise control over the ultrasound field parameters experienced by biological samples during sonication experiments in vitro may be quite challenging. The main goal of this work was to outline an approach to construction of sonication test cells that would minimize the interaction between the test cells and ultrasound. METHODS: Optimal dimensions of the test cell were determined through measurements conducted in a water sonication tank using 3D-printed test objects. The offset of local acoustic intensity variability inside the sonication test cell was set to value of ±50% of the reference value (i.e., local acoustic intensity measured at last axial maximum in the free-field condition). The cytotoxicity of several materials used for 3D printing was determined using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. RESULTS: The sonication test cells were 3D printed from polylactic acid material, which was not toxic to the cells. Silicone membrane HT-6240, which was used to construct the bottom of the test cell, was found to reduce ultrasound energy minimally. Final ultrasound profiles inside the sonication test cells indicated the desired variability of local acoustic intensity. The cell viability in our sonication test cell was comparable to that of commercial culture plates with bottoms constructed with silicone membrane. CONCLUSION: An approach to construction of sonication test cells minimizing the interaction of the test cell and ultrasound has been outlined.
OBJECTIVE: The aim of the study was to demonstrate that an administration of mucolytic solution with a maximum dose of simethicone and n -acetylcysteine before upper endoscopy improves mucosal visibility compared to a group without administration of mucolytic solution or water. METHODS: This study was a double-blind, randomized controlled trial. Patients were randomized into four groups, with the administration of 100 ml of water + 600 mg n -acetylcysteine + 400 mg simethicone, 100 ml of water + 400 mg n -acetylcysteine + 20 mg simethicone, 100 ml of water, and without any water or mucolytic solution. During the examination, a total of 10 images were taken in the defined areas. The overall visibility score was given by the sum of the 0-5 scores of the five areas and was assessed by the endoscopist performing the procedure and the blinded endoscopists using static images. RESULTS: A total of 129 patients were randomized. The group of patients did not differ in age, sex distribution, and indications significantly. The overall visibility score as assessed by the endoscopist performing the procedure was significantly higher in the group with the maximum dose of mucolytic solution compared to the group without solution or water (18.9 ± 2.9 vs. 16.6 ± 3.3, P = 0.023). This difference was not evident by the blinded evaluation of static photographs. CONCLUSION: Administration of mucolytic solution with a maximum dose of n -acetylcysteine and simethicone before upper endoscopy improved mucosal visibility in the upper gastrointestinal tract compared with the group without any preparation while evaluated by performing endoscopist.
- MeSH
- acetylcystein * MeSH
- dvojitá slepá metoda MeSH
- expektorancia * MeSH
- gastrointestinální endoskopie metody MeSH
- lidé MeSH
- simethikon MeSH
- voda MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
The research of novel implantable medical devices is one of the most attractive, yet complex areas in the biomedical field. The design and development of sufficiently small devices working in an in vivo environment is challenging but successful encapsulation of such devices is even more so. Industry-standard methods using glass and titanium are too expensive and tedious, and epoxy or silicone encapsulation is prone to water ingress with cable feedthroughs being the most frequent point of failure. This paper describes a universal and straightforward method for reliable encapsulation of circuit boards that achieves ISO10993 compliance. A two-part PVDF mold was machined using a conventional 3-axis machining center. Then, the circuit board with a hermetic feedthrough was placed in the mold and epoxy resin was injected into the mold under pressure to fill the cavity. Finally, the biocompatibility was further enhanced with an inert P3HT polymer coating which can be easily formulated into an ink. The biocompatibility of the encapsulants was assessed according to ISO10993. The endurance of the presented solution compared to silicone potting and epoxy potting was assessed by submersion in phosphate-buffered saline solution at 37 °C. The proposed method showed superior results to PDMS and simple epoxy potting.
BACKGROUND: Stickler syndrome (STL) is an inherited progressive connective tissue collagen disorder. STL is the most common hereditary cause of retinal complications, retinal tears, and the development of retinal detachment (RD) in childhood. The aim of the study was to evaluate the long-term anatomical and functional results of surgical treatment of retinal complications in children and adolescents affected by STL. METHODS: A retrospective, single-center study was performed a cohort of children with STL who underwent retinal surgery between 2004 and 2021. RESULTS: The study group consisted of nine children; the mean age at the time of the retinal tear with/without retinal detachment was 7.2 (2-10) years, and the mean follow-up period was 9.6 (5-16) years. Pathogenic variants COL2A1 (5 children) and COL11A1 (3 children) were confirmed in our cohort. In total, we operated on 13 eyes, 11 eyes with complicated RD and two eyes with multiple retinal defects, but without RD. At the end of the follow-up period, an attached retina was achieved 77% (10 eyes) with or without silicone oil tamponade: cryopexy alone was successful in one eye (10%), scleral buckling (EB) in five eyes (50%), and vitrectomy with silicone oil tamponade combined with EB in four eyes (40%). The mean number of surgeries was 2.3 per eye. The resulting best corrected visual acuity ranged from 0.03 to 0.1 in one eye, from 0.16 to 0.4 in two eyes, and from 0.5 to 1.0 in 7 eyes. CONCLUSION: Repair of retinal tears with/without retinal detachment in patients with Stickler syndrome often requires multiple surgeries with combinations of cryopexy, scleral buckling, and/or vitrectomy with silicone oil tamponade. Treatment of the ocular complications arising from STL requires long-term comprehensive care.
- MeSH
- bukláž skléry MeSH
- dědičné nemoci očí * chirurgie MeSH
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- odchlípení sítnice * diagnóza etiologie chirurgie MeSH
- perforace sítnice * chirurgie MeSH
- retina patologie MeSH
- retrospektivní studie MeSH
- silikonové oleje MeSH
- vitrektomie metody MeSH
- výsledek terapie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- Publikační typ
- časopisecké články MeSH
Magnetorheological elastomer (MRE) materials have the potential to be used in a wide range of applications that require long-term service in hostile environments. These widespread applications will result in the emergence of MRE-specific durability issues, where durability refers to performance under in-service environmental conditions. In response, the outdoor tropical climatic environment, combined with the effects of weathering, will be the primary focus of this paper, specifically the photodegradation of the MRE. In this study, MRE made of silicone rubber (SR) and 70 wt% micron-sized carbonyl iron particles (CIP) were prepared and subjected to mechanical and rheological testing to evaluate the effects under natural weathering. Magnetorheological elastomer samples were exposed to the natural weathering conditions of a tropical climate in Kuala Lumpur, Malaysia, for 30 days. To obtain a comprehensive view of MRE degradation during natural weathering, mechanical testing, rheology, and morphological evaluation were all performed. The mechanical and rheological properties test results revealed that after 30 days of exposure and known meteorological parameters, Young's modulus and storage modulus increased, while elongation at break decreased. The degradation processes of MRE during weathering, which are responsible for their undesirable change, were given special attention. With the help of morphological evidence, the relationship between these phenomena and the viscoelastic properties of MRE was comprehensively defined and discussed.
- MeSH
- elastomery * MeSH
- počasí MeSH
- reologie MeSH
- silikonové elastomery MeSH
- tropické klima * MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: A stent is a mesh tube inserted into a natural passage in the body to prevent disease induction. Self-expandable esophageal nitinol stents such as SX-ELLA Stent Esophageal HV (HV Stent Plus) can be indicated for palliation of malignant esophageal strictures, for the treatment of benign esophageal strictures that are refractory to standard therapy and for the treatment of esophago-respiratory fistulas. A silicone-stent coating is used for tumor in-growth prevention and esophago-respiratory fistula occlusion. The thickness of the stent and the overall integrity of the silicone coating of all wires indicate the overall mechanical properties of the esophageal stent and the resistance to external adverse events such as corrosion and mechanical and chemical resistance. METHODS: The polymer multicomponent epoxy resin - a mixture of Epon and Durcupan - was used as a method for robust sample stabilization. A cutting system using a thin water beam with a powder (Blue Line) was chosen as the best variant to obtain 6 samples for both-sided measurement (10 measuring sides). The optical microscopic reflective light method was used to examine wire crossing points in the sections. Fifty values were measured on either sample side for the internal, external and mesh thickness of the silicone stent layer. The wire crossing points were selected so that the silicone layer structure could be clearly seen, and the wires approached each other most closely. Only approximately 4 to 8 crossing points in each section could be measured when applying this approach. The resolution of the microscope and calibration (based on the camera used) was 0.677 μm/pixel. RESULTS: Additional data could be obtained on 8 planes. Two boundary samples were destroyed by the cutting process. Whole coating of the stent was around all mesh wires, especially in areas with higher mechanical stress (wire crossing). The minimum detectable and admissible value determined for all 3 measuring areas (internal, external, mesh) on the wire crossings was 6.77 μm, i.e., 10 pixels, based on the microscope resolution and manufacturer's methodology. The results were characterized by p < 0.001 for all 3 parameters. We tested opposite samples in each section to verify the section quality and data consistency. For the 4 areas, the data were significantly different, but the thickness differences were only on the order of units percent, so the measurements were not appreciably affected. We assume that the material cutting loss, making up 1-2 mm, contributed to the differences in the sections. CONCLUSION: We examined the overall integrity of the silicone coating of the esophageal stent. The method of HV stent anchoring in a polymeric bath followed by cutting with a waterjet and sample measurement under an optical microscope proved to be very simple and reliable. Sufficient thicknesses of the silicone layer on the wire cross sections were verified. The coated silicone layer thickness appeared to be significantly different along the stent from the proximal part to the distant part, presumably due to the manufacturing technology.
Hydrophobic fibrous slippery liquid-infused porous surfaces (SLIPS) were fabricated by electrospinning polydimethylsiloxane (PDMS) and polystyrene (PS) as a carrier polymer on plasma-treated polyethylene (PE) and polyurethane (PU) substrates. Subsequent infusion of blackseed oil (BSO) into the porous structures was applied for the preparation of the SLIPS. SLIPS with infused lubricants can act as a repellency layer and play an important role in the prevention of biofilm formation. The effect of polymer solutions used in the electrospinning process was investigated to obtain well-defined hydrophobic fibrous structures. The surface properties were analyzed through various optical, macroscopic and spectroscopic techniques. A comprehensive investigation of the surface chemistry, surface morphology/topography, and mechanical properties was carried out on selected samples at optimized conditions. The electrospun fibers prepared using a mixture of PDMS/PS in the ratio of 1:1:10 (g/g/mL) using tetrahydrofuran (THF) solvent showed the best results in terms of fiber uniformity. The subsequent infusion of BSO into the fabricated PDMS/PS fiber mats exhibited slippery behavior regarding water droplets. Moreover, prepared SLIPS exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli bacterium strains.
- MeSH
- dimethylpolysiloxany * MeSH
- Escherichia coli MeSH
- polymery chemie MeSH
- polystyreny * MeSH
- poréznost MeSH
- Publikační typ
- časopisecké články MeSH
Použití silikonového a latexového drénu je nedílnou součástí chirurgické praxe. Klinika i přehled světové literatury ukazují, že silikonový drén se vyznačuje mnohem nižší mírou fibrotické reakce tkáně kolem drénu. Schopnost latexového neboli pryžového či lidově nazývaného gumového drénu indukovat ve svém okolí tvorbu vaziva se s výhodou využívá v situacích, kdy je žádoucí cílené vytváření jizevnaté tkáně. Tato vlastnost u silikonových drénů absentuje. V dnešní době je však u většiny pracovišť pravidlem používání drénů téměř výlučně silikonových, které se zakládá na prevenci alergie na latex. Článek se věnuje popisu rozdílné a vzájemně nezaměnitelné reakce tkaniva na silikon a latex. Následně se také zabývá otázkou, jestli je soumrak používání latexového drénu v moderní medicíně doopravdy progresem, nebo spíše zpátečnictvím.
The use of silicone and latex drains is an integral part of surgical practice. Experience and the review of the world literature show that silicone drain is characterized by a much lower rate of fibrotic reaction of the tissue around the drain. The ability of a latex, or rubber, or popularly called rubber drain, to induce the formation of ligaments in its surroundings is advantageously used in situations where the targeted formation of scar tissue is desired. This feature is absent in silicone drains. However, nowadays the rule in most surgical departments is to use almost exclusively silicone drains, which is based on prevention of latex allergy. This article is devoted to the description of the different and mutually irreplaceable use of silicone and latex drains. Subsequently, he also discusses the question of whether the twilight of the use of latex drains in modern medicine is really progress, or rather retrogression.
