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Abstract This study evaluated physicochemical properties of experimental infiltrants after addition of hydroxyapatite nanoparticles (HAp) or 58S bioactive glass (BAG) and diphenyliodonium hexafluorophosphate (DPI). The resin matrix was composed of TEGDMA/Bis-EMA (3:1), 0.5 mol% CQ, and 1 mol% EDAB. The blends received or not 0.5 mol% DPI and 10% wt BAG or HAp. Icon was used as commercial control. The groups were characterized by XRD, FT-IR spectrometry, and SEM before and after simulated body fluid (SBF) immersion for up to 7 days. Polymerization kinetics (n =3 ), water sorption and solubility (n=10), and viscosity (n = 3) were surveyed. For polymerization kinetics, the samples were polymerized for 5 min and the data were obtained from 40 s and 5 min. Statistical analysis was made using ANOVA and Tukey's test (a = 0.05). After 7 days of SBF immersion, XRD and FT-IR showed that the HAp crystalline phase was present only in the HAp groups. A lower degree of conversion (DC) and polymerization rate were observed for the Icon and BAG groups, whereas HAp showed higher values. For the BAG group, DPI increased polymerization rate and DC in 40 s. After 5 min, all groups presented DC above 80%. In groups with particles, the HAp groups exhibited higher viscosity, whereas DPI groups showed a decrease in viscosity. Icon had the highest water sorption. To conclude, BAG neither improved the physicochemical properties studied, nor did it show bioactive properties. The addition of DPI reduced viscosity caused by particle addition and also attenuated the DC decrease caused by BAG addition. The addition of bioactive particles to infiltrants should be seen with caution because they increase viscosity and may not bring major clinical improvements that justify their use. DPI might be indicated only if any component is added to the infiltrant to act as a compensation mechanism.
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Objective:To produce 161Tb from enriched 160Gd 2O 3 isotope-enriched target material and realize domestic production of the novel medical isotope 161Tb. Methods:The 160Gd 2O 3 isotope-enriched target material was irradiated with neutrons by the China Mianyang Research Reactor (CMRR). The no-carrier-added 161Tb product was obtained after the processes of target broken, sample dissolution, separation and purification with lanthanide (LN) resin and solution replacement with diglycolamide (DGA) column. Various key indicators such as γ spectral purity, metal impurity content, specific activity, radiochemical purity, and radioactive concentration were used to conduct the quality inspection and the control of 161Tb products. Results:161TbCl 3 of 33.4 GBq was obtained in a single time with the radioactive concentration of 16.8 GBq/ml, nuclear purity more than 99.9%, and radiochemical purity of 99.2%. Metal impurity content was met the established standards, with the specific activity of 6.02×10 17 Bq/mol. The radiochemical purities of 161Tb labeling with 1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid- D-Phe1-Tyr3-Thr8-octreotide (DOTATATE) after 0 and 72 h were 100% and 95.8% respectively. Conclusion:The preparation of no-carrier-added 161Tb by using LN resin has the advantages of high separation performance and high sample loading, which has great significance in the field of medical isotope preparation and lays a good nuclide guarantee for the research and development of domestic 161Tb-labeled drugs.
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Abstract The composition of infiltrants can influence their physical properties, viscosity and depth of penetration (DP). Strategies are used to increase the DP, such as the addition of diluents or the use of heat. This study aimed to evaluate the effect of preheating and composition on physical properties and DP of infiltrants in demineralized enamel. The groups were assigned, and the following experimental formulations were made: 25%BisEMA +75%TEGDMA; 25%BisEMA +65%TEGDMA +10%ethanol; 25%BisEMA +65%TEGDMA +10%HEMA; 100%TEGDMA; 90%TEGDMA +10%ethanol; 90%TEGDMA +10%HEMA. The samples were photoactivated at two temperatures (25°C and 55°C). Degree of conversion (DC) was performed using an infrared spectrophotometer. Elastic modulus (E), flexural strength (FS) and contact angle (CA) tests were also performed. The DP of an infiltrant in demineralized enamel was determined by confocal laser scanning microscopy (CLSM) using an indirect labeling technique. The data were analyzed by two-way ANOVA and Tukey's test. DC increased after preheating in all the groups; however, 90%TEGDMA+10%ethanol showed the lowest DC for both temperatures, and the lowest E. Preheating did not influence E or FS. The CA increased at 55°C for most groups, but decreased for groups containing HEMA. Temperature did not seem to influence DP, and Icon showed the lowest DP values. The 100%TEGDMA composition showed more homogeneous penetration, whereas Icon showed heterogeneous and superficial penetration. The preheating technique does not improve all properties in all the material compositions. The composition of a material can influence and improve its properties.
Subject(s)
Dental Enamel , Polyethylene Glycols , Polymethacrylic Acids , Viscosity , Materials Testing , Bisphenol A-Glycidyl Methacrylate , Composite Resins , Elastic Modulus , MethacrylatesABSTRACT
Los medios de fijación a base de resinas compuestas para cementado, no son más que una resina compuesta fluida, que contiene un menor porcentaje de relleno inorgánico. Es por esto que en la actualidad, algunos autores plantean el uso de resina compuesta de restauración como medio de fijación de restauraciones indirectas (inlay fabricado en cerómero). Dicha resina debe ser fluidificada con calor (50ºC), para posteriormente ser fotoactivada por un tiempo adecuado. Asimismo, como se trata de un material cuya reacción de polimerización sólo es activada por luz, surge la pregunta de si será capaz de ser fotoactivada eficazmente como para polimerizar correctamente, en especial en las zonas más profundas de la preparación cavitaria. El presente estudio busca analizar si existen diferencias en el grado de sellado marginal y en la profundidad de curado de restauraciones cementadas con un medio de fijación a base de resina, previa técnica de grabado y colocación de adhesivo y con una resina compuesta a través de la técnica fluidificada.
The fixing means based on composite resins for cementing, are nothing more than a fluid composite resin, which contains a lower percentage of inorganic filler. This is why, at present, some authors propose the use of composite resin restoration as a means of fixing indirect restorations (inlay made of ceramics). Said resin must be fluidized with heat (50 ° C), to be photoactivated for a suitable time. Also, since it is a material whose polymerization reaction is only activated by light, the question arises whether it will be able to be effectively photoactivated to properly polymerize, especially in the deeper areas of the cavity preparation. The present study aims to analyze if there are differences in the degree of marginal sealing and in the depth of cure of cemented restorations with a resin-based fixing medium, prior to etching and adhesive placement and with a composite resin through the fluidized technique.
Subject(s)
Cementation/instrumentation , Inlays , Composite Resins/chemistry , Acid Etching, Dental/methods , Light-Curing of Dental Adhesives , Materials Testing , Resins, Synthetic/chemistryABSTRACT
Objective: To investigate if short-term dentin bleaching with low-concentrated substances affects the bond strength of immediate resin composite restorations. Material and Methods: The buccal surfaces of fifty molar crowns were ground for dentin exposure and randomly assigned into 5 groups (n=10), according to the following treatments: sodium perborate + water; sodium perborate + 6% hydrogen peroxide; 6% hydrogen peroxide; 35% hydrogen peroxide (positive control), or no bleaching agent (negative control). The specimens were immediately restored with resin composite. Seven days after treatments, the shear bond test was performed in a universal test machine at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukeys HSD test (α = 0.05). Results: The shear bond strength mean values for the negative control group were higher than all experimental and positive control groups (p < 0.000), whose differences were not statistically significant (p > 0.05). Conclusion: Short-term dentin bleaching with sodium perborate+water, 6% hydrogen peroxide, or sodium perborate mixed with 6% hydrogen peroxide reduced the shear bond strength of immediate resin composite restorations.
Objetivo: Investigar se o clareamento rápido da dentina com substâncias de baixa concentração afeta a resistência de união ao cisalhamento de restaurações imediatas de resina composta. Material e Métodos: As superfícies vestibulares de cinquenta molares foram desgastadas para exposição da dentina e então aleatoriamente alocadas em 5 grupos (n = 10), de acordo com as substâncias clareadoras: perborato de sódio + água; perborato de sódio + peróxido de hidrogênio a 6%; peróxido de hidrogênio a 6%; peróxido de hidrogênio a 35% (controle positivo); ou nenhum agente clareador (controle negativo). Os espécimes foram imediatamente restaurados com resina composta. Sete dias após os tratamentos, testes de resistência ao cisalhamento foram realizados em uma máquina de ensaios universal a uma velocidade de cruzeta de 0,5 mm/min. Os dados foram analisados com os testes ANOVA e Tukey HSD (α = 0,05). Resultados: Os valores de resistência ao cisalhamento do grupo controle negativo foram maiores do que os dos grupos experimentais e controle positivo (p < 0,001), cujas diferenças não foram estatisticamente significativa (p > 0,05). Conclusão: Clareamentos dentinários rápidos com perborato de sódio, peróxido de hidrogênio 6% ou perborato de sódio misturado com peróxido de hidrogênio 6% reduziram a força de resistência ao cisalhamento de restaurações imediatas de resina composta.
Subject(s)
Esthetics, Dental , Hydrogen Peroxide , Resins, Synthetic , ToothABSTRACT
Objective: To explore the reinforcement of polyglycidyl methacrylate ( PGMA ) pre-impregnated quartz fiber mesh in denture base materials by investigation of interface compatibility and fracture resistance .Methods: 1-layer, 2-layer, 3-layer PGMA pre-impregnated quartz fiber meshes , electrolyzed cobalt-chromium alloy mesh and cobalt-chromium alloy mesh conditioned by metal primer were integrated in polymethyl methacrylate ( PMMA) resin by sandwich embedding method .Block sam-ples of 5 groups were prepared (40 mm ×15 mm ×2 mm).Fracture resistance was determined in a 3-point bending test at 2 mm/min.Scanning electron microscope (SEM), micrographs were taken from the fractured surfaces to analyze the bonding interface compatibility .Results: The group of 3-layer PGMA pre-impregnated quartz fiber mesh presented the highest elastic modulus of 6 406 MPa and flexural strength of 227 MPa among the five groups , while the 1-layer and 2-layer expressed the similar elastic modulus and flexural strength to the pure PMMA group .The metal groups demonstrated better mechanical properties, while the metal surface conditioner played much better .The metal surface conditioner pre-impregnated cobalt-chromium alloy and PGMA pre-impregnated quartz fiber mesh showed compatible in-terface with PMMA.Conclusion:The mechanical properties were improved by the increasing of the fiber by adding the more meshed .Although the benign interface did help the compatibility , the quantity of the fibers played an important role in the strength .
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Objective: To evaluate the biocompatibility of polymethylmethacrylate(PMMA) denture base resin containing silver-supported antimicrobial agent STR-1 of nanometer level in vitro. Methods: According to the national standards for biological evaluation of dental materials, the cytotoxicity of denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was examined by molecular filtrating method, and the hemolysis of STR-1, denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was also surveyed. Results: The control denture base resin without containing STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were not cytotoxic to L929 cells. Two hours and 24 hours after cell culturing, the filter membranes of the control and experimental groups were stained evenly with blue color. The staining intensity was not decreased and the fading areas were 0 mm~2 during the culturing. The cytotoxicity grades were 0. The hemolysis rates of the antimicrobial agent STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were 1.7%, 3.5% and 3.7% respectively. They were less than the national guild standard 5% which represent no hemolysis. Conclusion: The PMMA denture base resins containing silver-supported antimicrobial agents STR-1 of nanometer level at concentrations of 5 g/L and 10 g/L exhibit good biocompatibility.
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Objective To establish 3D data-base on artificial resin teeth with 3D layer scanning digitizer. Methods Artificial resin teeth were measured with a CMS-400 3D digitizer by cutting and scanning layer-by-layer, 3D data points of each tooth acquired and the 3D models of these teeth reconstructed with a computer. Results 3D models of 3D data-base on artificial resin teeth were obtained. The characteristics of these 3D images were clear and accurate. Conclusion The complicated teeth moulds can be measured accurately with the 3D digitizer since there are no measuring blind spots.
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Objective To study the effects of resin absorptive devices combined with hemodialyzer in series treatment for patients with uremia.Methods Sixty maintenance hemodialysis patients with uremia were randomly divided into two groups: the experimental group and control group. The patients in experimental group were given the treatment for traditional hemodialysis two or three times a week,combined with the treatment for resin absorption twice a month.The patients in the control group were only given the treatment for traditional hemodialysis two or three times a week.The middle molecular substance(MMS),beta(2) microglobulin(?_2-MG),blood urea nitrogen,creatinine,albumin,globulin,the counts of red blood,hemoglobin,the change of blood pressure and clinical manifestation of the patients were observed before and three months after the treatment respectively.Results The rates of clearance of MMS and ?_2-MG were significantly higher in the experimental group than those of the control group(P