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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 30 (2003), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary The purpose of this study was to evaluate the stress distribution under various loading conditions within posterior all-ceramic crowns. A three-dimensional finite element model representing a lower first molar was constructed. Variations of the model had two types of single layer all-ceramic crowns (Dicor and Empress) and two types of double layer all-ceramic crowns (In-Ceram and Empress2) cemented. A load of 600 N, simulating the maximum bite force, was applied vertically to the crowns. Loads of 225 N, simulating masticatory force, were applied from three directions (vertically, at a 45° angle, and horizontally). In the test simulating maximum bite force, the maximum tensile stresses on all crowns (17·4–19·4 MPa) concentrated around the loading points. In the masticatory force simulation test, the specimens experienced maximum tensile stresses of 19·7–27·0 MPa under a horizontal load and 10·8–10·9 MPa under a vertical load. When the load was applied horizontally, the maximum tensile stress was observed around the loading points on the surface in the case of the single layer crowns, and of the cervical area of the inner core of the double layer crowns. Within the limitation of this study, it was found that the strength of occlusal contact points is important to the integrity of posterior all-ceramic crowns and that bite forces applied from the horizontal direction are a critical factor.
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  • 2
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The aim of the present study was to evaluate the mechanical strength of the Empress2 system, which is based on the use of a high-strength glass--ceramic core of lithium disilicate, and the fracture resistance of fixed partial dentures fabricated with this material. To evaluate mechanical strength, four types of ceramic materials were tested for four-point flexural strength and diametral tensile strength: Empress2 core material, Empress2 layering porcelain, conventional Empress material and Dicor. Then, using Empress2, conventional Empress and Dicor, actual clinical type anterior fixed partial dentures were fabricated for fracture testing. The results showed that the Empress2 core material, at 329 MPa, has more than twice the flexural strength of conventional materials and at 271 MPa, more than four times the diametral tensile strength of conventional materials. Furthermore, fixed partial dentures fabricated with Empress2 had a fracture resistance of 1424 N. That is, they were more than twice as fracture resistant as fixed partial dentures made with conventional materials.
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  • 3
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Auger transition probabilities were experimentally derived from dominant XAES and related XPS peaks observed in XPS spectra. Some values of derived probabilities were higher than 1, because of addition or subtraction of background signal from the XAES or/and XPS peak intensity. However, the probabilities obtained are recognized to be useful for practical quantification by XAES and AES.
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  • 4
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé  On a examiné les résultats oncologiques et fonctionnels de 33 patients ayant reçu une radiothérapie peropératoire pour un ostéosarcome d’une extrémité. Sur les sept cas de récidive locale identifiés, six se situaient dans une région apparemment non irradiée, ce qui indique que la défaillance locale pourrait être due à un défaut de détermination du territoire irradié. Sur les 33 patients, 14 ont reçu une endoprothése et 7 été amputés après la radiothérapie. Les tumeurs irradiées ont été laissées in situ chez les 12 patients restants. Dans ce dernier groupe, l’examen radiologique n’a révélé aucune dégénérescence au niveau des articulations. Des complications locales ont été observées chez 26 patients sur 33. La complication la plus problématique était la fracture de l’os irradié. La consolidation par enclouage médullaire a donné des résultats encourageants pour la prévention des fractures. Bien que la radiothérapie peropératoire soit efficace pour la maitrise locale de l’ostéosarcome des extrémités, la sélection judicieuse des patients et l’amélioration de la procédure sont nécessaires pour obtenir un membre fonctionnel à long terme.
    Notes: Abstract  The outcome following intra-operative radiation therapy in the treatment of osteosarcoma in the extremity in 33 patients was evaluated for oncological and functional results. Local recurrence occurred in seven cases, six of which were in a non-irradiated region, indicating inappropriate planning of the radiation field. Twenty-one patients underwent either prosthetic replacement (14) or amputation (7). Irradiated tumours were left in situ in the remaining 12 patients. In this latter group no degenerative joint changes were observed radiologically. Twenty-six patients experienced local complications, of which fracture of the irradiated bone was the most significant. Associated intramedullary nailing showed encouraging results in preventing fracture. Although IORT is effective for the local control of osteosarcoma in extremities, critical patient selection and improvements of treatment protocol are required in order to obtain a satisfactory outcome.
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  • 5
    ISSN: 1432-2277
    Keywords: Key words Non-episode biopsy ; Arteriolopathy ; Cyclosporine ; Tacrolimus ; Renal transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Histopathological findings in renal allograft with stable function remain unclear. We therefore performed non-episode biopsy in the long-surviving renal allograft to investigate the histopathological changes. Our data show that, although arteriolopathy is characteristic of drug-induced nephropathy, it is unrelated to dosage and concentration of cyclosporine or tacrolimus in non-episode biopsy. We evaluated therefore the clinicopathological findings of arteriolopathy in this study. Non-episode biopsy was defined as follows: as serum creatinine level lower than, 2.0 mg/dl and a urinary protein level lower than 500 mg/day. A total of 65 biopsy specimens were enrolled in this study as non-episode biopsy. Twenty-nine specimens revealed arteriolopathy. There were no statistically significant differences between arteriolopathy and dosage or concentration of cyclosporine or tacrolimus. Arteriolopathy in non-episode biopsy was related to time of biopsy, kidney age, hypertension, and hyperlipidemia, suggesting that it is important for graft survival to strictly control blood pressure and blood lipid level.
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  • 6
    ISSN: 1432-0428
    Keywords: Keywords Hormone sensitive lipase, obesity, respiratory quotient, skeletal muscle, visceral fat.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Fat balance is critical in the aetiology of obesity and related diseases. Lipoprotein lipase is of major importance in lipid metabolism. The aim of this study was to investigate the long-term effects of the lipoprotein lipase activator, NO-1886, on substrate utilisation, adiposity and insulin action in rats fed a high-fat diet.¶Methods. Male, Sprague-Dawley rats were fed for 10 weeks on a chow diet or a high-fat diet with, or without, NO-1886 (50 mg · kg–1· day–1). Weight gain, fat accumulation and both hormone-sensitive and lipoprotein, lipase activities were measured. Insulin action was assessed by the euglycaemic hyperinsulinaemic clamp and metabolic rate/substrate utilisation by open-circuit respirometry.¶Results. Compared with chow-fed controls, a high-fat diet increased weight gain, an effect lessened by NO-1886 [weight gain (g): chow, 37 ± 3, high-fat, 222 ± 9; high-fat + NO-1886, 109 ± 6, all groups differed p 〈 0.001]. A similar pattern existed for fat accumulation [visceral fat (g): chow, 35.9 ± 3.2; high-fat, 81.9 ± 6.6; high-fat + NO-1886, 52.3 ± 4.7, p 〈 0.01 high-fat vs the other groups]. A high-fat diet induced whole-body insulin resistance (clamp glucose infusion rate: 4.8 ± 1.3 mg · kg–1· min–1 vs 10.6 ± 1.1 for the chow group, p 〈 0.01) with NO-1886 lessening this effect (8.3 ± 0.5, p 〈 0.05 vs high-fat). The 24-h respiratory quotient was lower in the high-fat + NO-1886 group (0.825 ± 0.010) compared with high-fat alone (0.849 ± 0.004, p 〈 0.05). A high-fat diet increased lipoprotein and hormone-sensitive, lipase activities in epididymal fat, an effect not altered by NO-1886. In myocardium and skeletal muscle a high-fat diet lowered lipoprotein lipase activity, an effect lessened by NO-1886.¶Conclusion/interpretation: Lipoprotein lipase activators could have potential benefits for the treatment of obesity by increasing fat utilisation. [Diabetologia (2000) 43: 875–880]
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  • 7
    ISSN: 0992-7689
    Keywords: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides) ; Ionosphere (ionospheric disturbances)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Averaged seasonal variations of wind perturbation intensities and vertical flux of horizontal momentum produced by internal gravity waves (IGWs) with periods 0.2/1 h and 1/6 h are studied at the altitudes 65/80 km using the MU radar measurement data from the middle and upper atmosphere during 1986/1997 at Shigaraki, Japan (35°N, 136°E). IGW intensity has maxima in winter and summer, winter values having substantial interannual variations. Mean wave momentum flux is directed to the west in winter and to the east in summer, opposite to the mean wind in the middle atmosphere. Major IGW momentum fluxes come to the mesosphere over Shigaraki from the Pacific direction in winter and continental Asia in summer.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 31 (2004), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  The purpose of this study was to examine the translucency of glass-fibre-reinforced composite framework materials. Vectris and FibreKor, as well as an experimental material, were the glass-fibre-reinforced framework materials used. Targis, Sculpture and Estenia were the types of particulate filler composites veneered onto frameworks. Specimens were fabricated from each material, 0·5 and 1·0 mm thick. In addition, laminate specimens, 1·5 mm thick, were fabricated. The translucency of each specimen was evaluated by determining its contrast ratio. The laminate specimens were examined for colour differences. The experimental framework material was more translucent than the enamel composite when it was not coloured, and was nearly as translucent as the dentine composite when coloured. The commercial tooth-coloured framework materials were nearly as translucent as the dentine composite. It was found that it was possible to reproduce the same colour as the veneering dentine composite, when the framework thickness was 0·5 mm, except in the case of FibreKor. Within the limitations of this study, tooth-coloured, glass-fibre-reinforced framework materials are nearly as translucent as the veneering dentine composite, but these materials affect the colour of the prosthesis if the thickness of the framework material is increased beyond a certain point.
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  • 9
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  New-generation composite materials have excellent strength and wear resistance, and thus can be used to make metal-free crowns. However, composite materials are translucent, and so when using them to make metal-free crowns, it is necessary to take the effect of the abutments into consideration. In this study, five types of materials including three types of new-generation composite materials, a conventional composite material, and a ceramic material were used to examine the translucency (contrast ratio) of the materials and the effects of the colour of the abutments on the final appearance of metal-free crowns. It was found that the materials varied slightly from one-another in translucency and that it was possible to reproduce the desired colour when gold alloy was used for the background. However, it was difficult to produce an adequate colour match when silver–palladium alloy was used for the background. When a tooth colour material that was darker than the target colour was used for the abutment teeth, some materials could not reproduce the target colour satisfactorily.
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  • 10
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary All-ceramic crowns made of leucite-based heat-pressed ceramics are widely used to restore non-vital teeth in conjunction with various post and core materials. However, as some light passes through the ceramic, the colour of the abutment substrate can negatively affect the final aesthetic appearance of the all-ceramic crown. In this study, we made background specimens simulating gold-alloy cast posts and other simulating porcelain veneered cast posts, overlaid different thickness of heat-pressed ceramic on these background specimens, and measured the shifts in colour. We found that, when the background specimen was a gold alloy, the background colour had an effect on the apparent colour, unless the ceramic was more than 1·6 mm thick. When the background specimen was porcelain veneered, the background colour had no evident effect, even when the ceramic was not very thick. Therefore, when making a restoration using a leucite-based heat-pressed ceramic crown, it is advisable to use tooth-coloured materials such as a porcelain veneered cast post, if you will not be able to make the ceramic more than 1·6 mm thick.
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