flexural strength
Dotaz
Zobrazit nápovědu
- MeSH
- modul pružnosti MeSH
- pevnost v ohybu MeSH
- statistika jako téma MeSH
- testování materiálů metody přístrojové vybavení MeSH
- zubní fazety * klasifikace MeSH
- zubní materiály * analýza klasifikace terapeutické užití MeSH
- zubní porcelán analýza klasifikace terapeutické užití MeSH
- Publikační typ
- práce podpořená grantem MeSH
- srovnávací studie MeSH
The aim of this study was to investigate the restorative connections of composite materials after fracture, under controlled conditions of treating the materials with novel, spherosilicate-based (SS) primers bearing both methacryl (MA) and trimethoxysilyl (TMOS) groups. The chemistry of methacrylate group insertion and reactive groups hydrolysis has been studied with the aid of 1H NMR (Nuclear Magnetic Resonance) spectroscopy. The light-cured resin composites were repaired by activating the connection site with the obtained primers and, for comparison, a silane (methacryloxypropyltrimethoxysilane, MATMOS) as a conventional coupling agent bearing the same reactive groups. The resistance of such a joint was tested in a three-point bending test after 24 h and 28 days period of sample conditioning. The effect of bond application was also studied, showing that spherosilicate-based primers may be used more effectively than MATMOS for two-step (primer-composite) restorative process, while for silane, the three-step process with bond application is crucial for satisfactory joint quality. The joint failure mode was determined by microscopic analysis and it was found that SS-4MA-4TMOS and SS-2MA-6TMOS application resulted in mostly composite, and not joint, failure. After 28 days of conditioning, the flexural strength of the joint repaired with SS-4MA-4TMOS was at 94% of the neat, solid material under the same procedure. However, the strength of the neat composite was observed to decline during the conditioning process by ~30%. The joint behavior was explained on the basis of the gradual hydrolysis effect (the greatest decrease being observed for silane).
- Publikační typ
- časopisecké články MeSH
The adhesive systems have the function to establish the connection between the restorative material and dental tissue, therefore it is of fundamental importance, because failures in the adhesive interface can reduce the life of a dental restoration. This study investigated the possibility of using the adhesive layer as a chlorhexidine modified release system evaluating their impact on the properties of these systems as well as evaluating the impact of these systems on immediate and post-aging dentin adhesion. Were used a matrix with BisGMA, UDMA, HEMA and TEGDMA copolymer and clay particles (Dellite 67G); associated with a chlorhexidine and a camphorquinone photoinitiator system. The properties of these systems were evaluated by the XRD, FTIR spectrophotometer, flexural strength, elasticity modulus, drug release, enzymatic inhibition and dentin adhesion resistance. The presence of the clay can raise the mechanical properties of the adhesive systems engendering a more resistant hybrid layer and led to a more sustained release of chlorhexidine in the systems, allowing a longer effective period of MMP-2 inhibition. The hypothesis that the addition of clays as release modulators could increase the effectiveness of these drugs in inhibiting the dentin's MPPs and consequently enhancing the adhesive durability was confirmed. These results indicate that the controlled release of chlorhexidine is able to reduce the process of loss of adhesion presenting itself as a promising system to increase the longevity of dental restorations.
- MeSH
- biokompatibilní materiály MeSH
- časové faktory MeSH
- chlorhexidin chemie MeSH
- dentin chemie MeSH
- dentinová adheziva MeSH
- jíl chemie MeSH
- léky s prodlouženým účinkem MeSH
- pevnost v tahu MeSH
- testování materiálů MeSH
- uvolňování léčiv * MeSH
- zubní materiály * MeSH
- Publikační typ
- časopisecké články MeSH
Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone.
- MeSH
- hořčík chemie MeSH
- hutnictví metody MeSH
- hydrogenuhličitany chemie MeSH
- koncentrace vodíkových iontů MeSH
- koroze MeSH
- mikroskopie elektronová rastrovací MeSH
- poréznost MeSH
- prášky, zásypy, pudry MeSH
- spektrometrie rentgenová emisní MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
STATEMENT OF PROBLEM: Artificial denture teeth made of polymethyl methacrylate (PMMA) resin have good adhesion to the denture base but are relatively soft and have limited wear resistance during function. PURPOSE: The purpose of this in vitro study was to evaluate the influence of the addition of 2 inorganic nanofillers on the flexural strength, maximal displacement, elastic modulus, Isolde impact resistance, and Brinell hardness of acrylic resin denture teeth. MATERIAL AND METHODS: Heat polymerizing polymethyl methacrylate resin was mixed with silanized silica or silanized feldspar in concentrations of 5 wt%, 10 wt%, and 15 wt%. The first test was conducted after 24 hours of storage in laboratory conditions, and the second assessment was conducted after 3 months of storage in distilled water at 37 °C. The Brinell hardness was evaluated, and the elastic modulus and maximal displacement at fracture were calculated. The flexural strength and Isolde impact resistance were measured with a 3-point flexural test. Acrylic resin specimens without filler addition were used as a control group. Statistical analysis included 2-way ANOVA for independent variables (α=.05) and the Student t test for time-dependent changes (α=.05). These were performed with Statistica 12 software. RESULTS: The acrylic resin specimens modified with the addition of silanized feldspar had significantly higher Brinell hardness, elastic modulus, maximal displacement, and flexural strength and also had no adverse effect on Isolde impact resistance compared with the conventional acrylic resin. Silica filler increased the Brinell hardness and elastic modulus of acrylic resins but significantly reduced the flexural strength and Isolde impact resistance.
- MeSH
- lidé MeSH
- mechanický stres MeSH
- ohebnost (fyzika) MeSH
- oxid křemičitý * MeSH
- polymethylmethakrylát * MeSH
- povrchové vlastnosti MeSH
- silikáty hliníku MeSH
- sloučeniny draslíku MeSH
- testování materiálů MeSH
- zubní materiály MeSH
- zubní náhrady - baze MeSH
- zubní náhrady MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Restorative composites are subjected to various influences in the oral cavity environment, such as high or low temperatures, the mechanical force generated during mastication, colonization of various microorganisms, and low pH, which may result from ingested food and the influence of microbial flora. This study aimed to investigate the effect of a recently developed commercial artificial saliva (pH = 4, highly acidic) on 17 commercially available restorative materials. After polymerization, the samples were stored in an artificial solution for 3 and 60 days and subjected to crushing resistance and flexural strength tests. The surface additions of the materials were examined in terms of the shapes and sizes of the fillers and elemental composition. When stored in an acidic environment, the resistance of the composite materials was reduced by 2-12%. Larger compressive and flexural strength resistance values were observed for composites that could be bonded to microfilled materials (invented before 2000). This may result from the filler structure taking an irregular form, which results in a faster hydrolysis of silane bonds. All composite materials meet the standard requirements when stored for a long period in an acidic environment. However, storage of the materials in an acid environment has a destructive impact on the materials' properties.
- Publikační typ
- časopisecké články MeSH
UNLABELLED: The aim of this study was to create a 3D printing material with bioactive properties that potentially could be used for a transparent removable orthodontic appliance. MATERIALS AND METHODS: To acrylic monomers, four bioactive glasses at 10% concentration were added, which release Ca, P, Si and F ions. The materials were printed on a 3D printer and tested for flexural strength (24 h and 30 days), sorption and solubility (7 days), ion release to artificial saliva pH = 4 and 7 (42 days) and cytotoxicity in the human fibroblast model. The released ions were determined by plasma spectrometry (Ca, P and Si ions) and ion-selective electrode (F measurement)s. RESULTS: The material obtained released Ca2+ and PO43- ions for a period of 42 days when using glass Biomin C at pH 4. The flexural strength depended on the direction in which the sample was printed relative to the 3D printer platform. Vertically printed samples had a resistance greater than 20%. The 10% Biomin C samples post-cured for 30 min with light had a survival rate of the cells after 72 h of 85%. CONCLUSIONS: Material for 3D printing with bioactive glass in its composition, which releases ions, can be used in the production of orthodontic aligners.
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The creation of the denture base material with bioactive properties that releases ions and produces hydroxyapatite. METHODS: Acrylic resins were modified by the addition of 20% of four types of bioactive glasses by mixing with powders. Samples were subjected to flexural strength (1, 60 days), sorption and solubility (7 days), and ion release at pH 4 and pH 7 for 42 days. Hydroxyapatite layer formation was measured using infrared. RESULTS: Biomin F glass-containing samples release fluoride ions for a period of 42 days (pH = 4; Ca = 0.62 ± 0.09; P = 30.47 ± 4.35; Si = 22.9 ± 3.44; F = 3.1 ± 0.47 [mg/L]). The Biomin C (contained in the acrylic resin releases (pH = 4; Ca = 41.23 ± 6.19; P = 26.43 ± 3.96; Si = 33.63 ± 5.04 [mg/L]) ions for the same period of time. All samples have a flexural strength greater than 65 MPa after 60 days. CONCLUSION: The addition of partially silanized bioactive glasses allows for obtaining a material that releases ions over a longer period of time. CLINICAL SIGNIFICANCE: This type of material could be used as a denture base material, helping to preserve oral health by preventing the demineralization of the residual dentition through the release of appropriate ions that serve as substrates for hydroxyapatite formation.
- Publikační typ
- časopisecké články MeSH
Předmět sdělení: Příměs syntetických vláken v kompozitních materiálech označovaných nejčastěji jako vlákny vyztužené kompozity (fiber reinforced composites) výrazně zlepšuje některé jejich fyzikální vlastnosti, zejména odolnost v tahu a v ohybu. Díky dobrým mechanickým vlastnostem a také nízké hmotnosti mají tyto materiály široké spektrum využití v mnoha oborech včetně medicíny. Uplatňují se i ve většině odvětví současné stomatologie, kde tvoří možnou a často i výhodnou alternativu mnoha standardním terapeutickým postupům. Základními složkami vlákny vyztužených kompozitů jsou kompozitní matrix a vlákna, která mohou být neimpregnovaná i preimpregnovaná, a dále silany, jež slouží jako vazebná činidla obou složek. Důležité je rovněž prostorové uspořádání vláken, která mohou být orientována jednosměrně, pletená nebo tkaná. Obvykle jsou jako výztuž použita vlákna skelná a polyetylenová, málo vhodná jsou ve stomatologii vlákna uhlíková. Materiály určené pro použití ve stomatologii se vyrábějí ve formě různě silných a dlouhých pásek, lanek nebo čepů, což je dáno způsobem jejich následného využití. Nejčastěji jsou vlákny vyztužené kompozity používány v protetice ke zhotovování kořenových nástaveb a provizorních i definitivních zubních náhrad, v parodontologii a dentoalveolární chirurgii k výrobě dočasných i trvalých stabilizačních dlah a v ortodoncii ke zhotovování retainerů po ukončení aktivní fáze ortodontické léčby. Kontraindikacemi pro jejich použití jsou zejména nespolupráce pacienta, nemožnost zajištění suchého pracovního pole a některé parafunkce, zejména bruxismus. Mezi hlavní výhody těchto materiálů patří příznivé mechanické a estetické vlastnosti, relativně nízká cena, možnost eliminace laboratorní fáze z pracovního postupu při protetickém ošetření a dlouhodobá trvanlivost výrobků. Obecně je zmíněna i technika práce s vlákny vyztuženými kompozity předpokládající dostatečné znalosti jejich vlastností a indikací.
Objectives: The synthetic fiber content significantly improves some physical properties of composite materials, such as tension and flexural resistence. These materials are known as the fiber reinforced composites. They have a wide spectrum of applications in many fields, including medicine, thanks to their low weight and a plethera of other advantageous mechanical properties. They are used in dentistry to provide greater range of favourable alternatives to many standard treatment methods. The basic components of fiber reinforced composites are resin matrix and fibers (nonimpregnated or preimpregnated) and silans, that work as bonding agents between matrix and fibers. The spatial distribution of fibers is also important for the quality of the material; the internal architecture of the fiber beams can be either unidirectional, braided or woven. The glass and polyethylene fibers are usually used as the reinforcement of material. The shapes of the materials for use in dentistry are commonly either posts or ribbons. The design of the products reflects their specific applications. The fiber reinforced composites are most frequently used in prosthetic dentistry for the post and core fabrication as well as for fabrication of temporary and permanent dentures. In periodontology and dentoalveolar surgery they are used for fabrication of stabilization splints with short-term or long-term usage, and in orthodontics as retainers after completion of the active treatment period. Contraindications of their include poorly cooperating patient, wet operating field and some parafunctions, such as bruxism. The favourable mechanical as well as aesthetic properties are the main advantages of the fiber reinforced composites. Other advantages include relatively low costs, the possibility of direct fabrication without any laboratory phase during prosthetic treatments and the long-term durability of material. Practical working procedures have previously been discussed in literature that reiterate the fact that a complete knowledge of the material´s properties and their indications is essential for their clinical use.
- Klíčová slova
- sklovláknové čepy, adhezivní fixní můstky, stabilizační dlahy,
- MeSH
- dentální technologie MeSH
- mechanický stres MeSH
- ohebnost (fyzika) MeSH
- pevnost v tlaku MeSH
- pružnost MeSH
- silany MeSH
- sklo * MeSH
- složené pryskyřice * MeSH
- stomatologie MeSH
- vazba zubní MeSH
- zubní čepy MeSH
- zubní materiály * chemie MeSH
- zubní náhrady částečné fixní MeSH
- zubní náhrady částečné snímatelné MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
This study aimed to prepare a bioactive acrylic material by adding different types of glasses. Commercially available polymerized acrylic resin was mixed with 10% of four different types of glasses in the powder form and cured. Flexural strength, sorption, and solubility of the samples were tested according to ISO 20795-1:2013. The total number of samples used in the tests were 60. The materials were placed in artificial saliva of pH 4 and 7, and elution was performed for 0, 1, 28, and 42 days. The collected samples were analyzed using inductively coupled plasma atomic emission spectrometry to detect Ca, P, and Si ions and using ion chromatography to detect F ions. The materials obtained after modification with glasses showed lower compressive strength compared with pure polymethyl methacrylate but met the standard requirements. Two glass types showed higher solubility values compared with the value defined by the ISO standard. Biomin C and S53P4 released Ca, P, and Si ions, respectively, after 42 days in artificial saliva. Acrylic resins modified with 10% Biomin C and S53P4 glasses can be a valuable source of Ca and P ions under acid conditions for 28 and 42 days.
