Transplantation in reconstructive surgery has been performed for more than 20 years, although the official beginning of these procedures is considered the first successful transplantation of the hand in 1998. The original name "Composite Tissue Transplantation" has been used less frequently; more common is the term "Vascularized Composite Allotransplant", which better describes the basis of the procedure. There have been so far approximately 180 transplantations performed, the exact number is difficult to find. The most known transplantation from this group include transplantation of the hand and face, the other, such as transplantation of the abdominal wall, joints, bones, trachea, larynx, tongue, penis, uterus, etc. are less common and less well known. The common characteristics is that they are not used for salvage or prolongation of life, but to improve its quality. The quality of life is a value, which cannot be objectively measured and the opinions regarding its importance significantly differ. Therefore there is still an unsolved ethical issue regarding these procedures, which is based on the justification to use immunosuppressive therapy with its serious risks in cases when the procedure is not needed for salvage or preservation of life.

• Klíčová slova
• Composite tissue transplantation, vascularized composite allograft reconstructive surgery.,
• MeSH
• lidé MeSH
• štěpy z kompozitní tkáně * imunologie   MeSH
• zákroky plastické chirurgie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The main goal of this study is to develop a micromechanical model of a particle-filled dental composite focused on the residual stress (RS) field developed during the curing process in its microstructure. A finite element model of a representative volume element of filler and resin was developed, and volumetric shrinkage was simulated during the curing process. Four material models (von Mises plasticity model, Drucker-Prager plasticity model, von Mises plasticity model with stress relaxation and Drucker-Prager plasticity with stress relaxation) of the polymer resin were built to assess the influence of the material model on the resulting internal stress. The relationship between the curing process and the magnitude of the stress components will be described, and an analysis of the post-curing state of the material in particular microstructure locations will be conducted in this study. Obtained RS is comparable to the stresses developed in the material under the external load. The substantial dependence on the choice of material model for resin is to be observed, and the suitability of particular models is discussed.

• Klíčová slova
• FE modelling, dental composite, plasticity, residual stress,
• MeSH
• analýza metodou konečných prvků MeSH
• analýza zatížení zubů * MeSH
• hydrostatický tlak MeSH
• mechanický stres * MeSH
• složené pryskyřice chemie   MeSH
• teoretické modely MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• složené pryskyřice MeSH

This article focuses on the computational analysis of sandwich composite materials based on polypropylene, polyester, glass, and cotton fibers. In the automotive components prepared from these fiber materials, the various components are used in different proportions. Through the manufacturing process, isotropic materials become somewhat anisotropic. Part of this article is aimed at obtaining input values of material characteristics for calculations using finite element analysis (FEM) and the comparison of experimental results with FEM-based material models created using the Digimat 2023.1 software. This article analyzes the modeling of two-phase as well as multiphase composite materials. This work focuses on calculations using FEM according to the test defined in the PR375 standard for loading the finished product in the luggage compartment of a car. The defined methodology enables the application of the FEM-based calculation directly to the product design in the initial phase of research. The construction and production of expensive prototypes and the subsequent production of automotive parts is replaced by computer-based simulation. This procedure makes it possible to simulate several optimization cycles over a relatively shorter time. From the results of computational simulations, it is clear that materials based on PP/PET/glass fibers show a much higher modulus of elasticity than materials created using cotton, i.e., materials of the PP/PET/cotton type. In order to achieve a high strength and stiffness, it is, therefore, appropriate to use glass fibers in the composite materials used for such applications.

• Klíčová slova
• FEM analysis, cotton, glass, polyester, polypropylene, sandwich composite materials,
• Publikační typ
• časopisecké články MeSH

The acoustic emission method has been adopted for detection of damage mechanisms in carbon-fiber-reinforced polymer composite tubes during the three-point bending test. The damage evolution process of the individual samples has been monitored using the acoustic emission method, which is one of the non-destructive methods. The obtained data were then subjected to a two-step technique, which combines the unsupervised pattern recognition approach utilizing the short-time frequency spectra with the boundary curve enabling the already clustered data to be additionally filtered. The boundary curve identification has been carried out on the basis of preliminary tensile tests of the carbon fiber sheafs, where, by overlapping the force versus time dependency by the acoustic emission activity versus time dependency, it was possible to identify the boundary which will separate the signals originating from the fiber break from unwanted secondary sources. The application of the presented two-step method resulted in the identification of the failure mechanisms such as matrix cracking, fiber break, decohesion, and debonding. Besides the comparison of the results with already published research papers, the study presents the comprehensive parametric acoustic emission signal analysis of the individual clusters.

• Klíčová slova
• CFRP composite tube, acoustic emission, failure mechanism, unsupervised learning approach,
• Publikační typ
• časopisecké články MeSH

• MeSH
• složené pryskyřice * MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• složené pryskyřice * MeSH

Composite veneers, crowns, and adhesive bridges also can be a part of interdisciplinary therapy, namely, cooperation between orthodontics and prosthodontics. This study sought to systematically analyze patients treated orthodontically and prosthodontically with permanent teeth from a long-term point of view (three years). Forty-nine composite veneers, crowns, and adhesive bridges were inserted on the anterior teeth of 20 patients as a part of reshaping and reorientation of teeth after orthodontic therapy. The results indicated that composite resin restoration, including fiber-reinforcement restoration, is the treatment of choice in anterior dentition.

• MeSH
• barva MeSH
• dospělí MeSH
• estetika stomatologická MeSH
• inleje * MeSH
• lidé MeSH
• motivace MeSH
• následné studie MeSH
• ortodoncie korekční * MeSH
• povrchové vlastnosti MeSH
• prospektivní studie MeSH
• složené pryskyřice * MeSH
• výsledek terapie MeSH
• zubní fazety * MeSH
• zubní korunky * MeSH
• zubní marginální adaptace MeSH
• zubní náhrady částečné fixní * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• složené pryskyřice * MeSH

OBJECTIVE: Exposure reciprocity suggests that, as long as the same radiant exposure is delivered, different combinations of irradiance and exposure time will achieve the same degree of resin polymerization. This study examined the validity of exposure reciprocity using real time degree of conversion results from one commercial flowable dental resin. Additionally a new fitting function to describe the polymerization kinetics is proposed. METHODS: A Plasma Arc Light Curing Unit (LCU) was used to deliver 0.75, 1.2, 1.5, 3.7 or 7.5 W/cm(2) to 2mm thick samples of Tetric EvoFlow (Ivoclar Vivadent). The irradiances and radiant exposures received by the resin were determined using an integrating sphere connected to a fiber-optic spectrometer. The degree of conversion (DC) was recorded at a rate of 8.5 measurements a second at the bottom of the resin using attenuated total reflectance Fourier Transform mid-infrared spectroscopy (FT-MIR). Five specimens were exposed at each irradiance level. The DC reached after 170s and after 5, 10 and 15 J/cm(2) had been delivered was compared using analysis of variance and Fisher's PLSD post hoc multiple comparison tests (alpha=0.05). RESULTS: The same DC values were not reached after the same radiant exposures of 5, 10 and 15 J/cm(2) had been delivered at an irradiance of 3.7 and 7.5 W/cm(2). Thus exposure reciprocity was not supported for Tetric EvoFlow (p<0.05). SIGNIFICANCE: For Tetric EvoFlow, there was no significant difference in the DC when 5, 10 and 15J/cm(2) were delivered at irradiance levels of 0.75, 1.2 and 1.5 W/cm(2). The optimum combination of irradiance and exposure time for this commercial dental resin may be close to 1.5 W/cm(2) for 12s.

• Klíčová slova
• Degree of conversion, Dental curing light, Exposure reciprocity, Flowable composite, Irradiance, Mid FTIR, Polymerization kinetics, Radiant exposure,
• MeSH
• dentální adheziva tuhnoucí světlem * MeSH
• polymerizace MeSH
• složené pryskyřice chemie   účinky záření   MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• stomatologické polymerizační lampy MeSH
• testování materiálů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• složené pryskyřice MeSH
• tetric flow composite resin MeSH Prohlížeč

A composite material was prepared consisting of silicone rubber matrix and particulate lightly cross-linked poly(2-hydroxyethyl methacrylate) (p(HEMA] hydrogel. The material resembling common silicone rubber is hydrophilic and swells in water like hydrogels. The effects of the implanted composite on tissues of the living organism were tested in rats by methods assessing local acute and chronic inflammatory reactions and calcification by means of radioactive indicators and by histological examination. Results of a 6 month implant study indicated no difference in reactions of the animal body on the silicone rubber-p(HEMA) composite and a non-toxic, non-irritant pure solid p(HEMA) control.

• MeSH
• biokompatibilní materiály * MeSH
• fibrin analýza   MeSH
• inbrední kmeny potkanů MeSH
• kolagen analýza   MeSH
• krysa rodu Rattus MeSH
• polyhydroxyethylmethakrylát * MeSH
• protézy a implantáty * MeSH
• radioisotopová scintigrafie MeSH
• radioizotopy india MeSH
• silikonové elastomery * MeSH
• složené pryskyřice * MeSH
• zánět diagnostické zobrazování   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní materiály * MeSH
• fibrin MeSH
• kolagen MeSH
• polyhydroxyethylmethakrylát * MeSH
• radioizotopy india MeSH
• silikonové elastomery * MeSH
• složené pryskyřice * MeSH

In our study we used holocelluloses from sugar beet and bagasse for film preparation. Films from sugar beet holocellulose have better mechanical properties than from bagasse holocellulose. By subsequent carboxymethylation of bagasse holocellulose, films with better properties were produced. Specimens prepared from combined sugar beet and bagasse carboxymethylated holocellulose had the best mechanical properties. The results could be explained by the ratios of cellulose, arabinan, polygalacturonan and xylan content in individual films, based on the elemental analysis data. The use of microwaves to prepare holocellulose film speed up the process, but negatively affected the mechanical properties. Lignin content of the sugar beet holocellulose and bagasse samples was low and did not affect the mechanical properties. Both types of agricultural by-products could be used for preparation of composite film with high strength and stiffness suitable for broad range of applications.

• Klíčová slova
• Bagasse, Composite film properties, Holocellulose, Sugar beet residue,
• MeSH
• Beta vulgaris chemie   MeSH
• celulosa chemie   MeSH
• lignin chemie   MeSH
• sodná sůl karboxymethylcelulosy chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bagasse MeSH Prohlížeč
• celulosa MeSH
• lignin MeSH
• sodná sůl karboxymethylcelulosy MeSH

This study investigated the effect of peroxide bleaching gel on the durability of the adhesive bond between composite material, enamel, and dentin created with the etch-and-rinse adhesive Gluma Comfort Bond (GLU) and with the self-etch adhesives Clearfil SE Bond (CLE), Adper Prompt (ADP), and iBond (IBO). The adhesives were applied to flattened enamel and dentin of extracted human molars and built up with a microhybrid composite (Charisma). After 25 eight-hour cycles of bleaching with a 20% carbamide peroxide bleaching gel (Opalescence PF 20), the shear bond strength was measured and compared with one-day and two-month control specimens stored in water. The data were analyzed using nonparametric Mann-Whitney and Kruskal-Wallis statistics (p<0.05). Detailed fractographic analysis was performed using scanning electron microscopy. The bleaching gel significantly decreased the bond strength on both enamel and dentin for the simplified single-step self-etch adhesives ADP and IBO and markedly affected a fracture pattern of ADP specimens at the periphery of their bonded area. The results of our study indicate that the durability of adhesive restorations can be detrimentally influenced by carbamide peroxide bleaching and that different adhesives show varying sensitivity levels to the bleaching gel.

• MeSH
• bělení zubů metody   MeSH
• bisfenol A-glycidyl methakrylát chemie   MeSH
• časové faktory MeSH
• dentin ultrastruktura   MeSH
• dentinová adheziva chemie   MeSH
• karbamidperoxid MeSH
• látky na bělení zubů chemie   MeSH
• leptání zubů kyselinou metody   MeSH
• lidé MeSH
• mechanický stres MeSH
• mikroskopie elektronová rastrovací MeSH
• močovina analogy a deriváty   chemie   MeSH
• organofosfáty chemie   MeSH
• peroxidy chemie   MeSH
• pevnost ve smyku MeSH
• povrchové vlastnosti MeSH
• pryskyřičné cementy chemie   MeSH
• složené pryskyřice chemie   MeSH
• testování materiálů MeSH
• vazba zubní * MeSH
• voda chemie   MeSH
• zubní materiály chemie   MeSH
• zubní sklovina ultrastruktura   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• randomizované kontrolované studie MeSH
• srovnávací studie MeSH
• Názvy látek
• Adper Prompt Self-Etch MeSH Prohlížeč
• bisfenol A-glycidyl methakrylát MeSH
• Charisma composite resin MeSH Prohlížeč
• Clearfil SE Bond MeSH Prohlížeč
• dentinová adheziva MeSH
• Gluma Comfort Bond MeSH Prohlížeč
• iBond MeSH Prohlížeč
• karbamidperoxid MeSH
• látky na bělení zubů MeSH
• močovina MeSH
• organofosfáty MeSH
• peroxidy MeSH
• pryskyřičné cementy MeSH
• složené pryskyřice MeSH
• voda MeSH
• zubní materiály MeSH