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Abstract  

Commercial light-cured dental composites were used in this study. Two laboratorial composites, Resilab (Wilcos/Brazil), Epricord (Kuraray/Japan) were compared under cured and uncured conditions. Thermal analysis, infrared spectroscopy and scanning electron microscopy were used to evaluate the dental composites. The mass change and heat flow signals (TG–DSC) were recorded simultaneously by using STA 409 PC Luxx (NETZSCH), in the 25–800 °C temperature range at a heating rate of 10 °C/min under nitrogen atmosphere (70 mL/min). Employing thermo-microbalance TG 209 C F1 Iris (NETZSCH) coupled to the BRUKER Optics FTIR TENSOR, the samples were analyzed by combined thermogravimetric and spectroscopic methods (TG–FTIR). The initial sample mass was about ~12 mg, the data collection have been done in the 35–800 °C temperature range at a heating rate of 20 K/min in nitrogen atmosphere (flow rate: 40 mL/min). Finally, superficial topographic was analyzed by scanning electron microscopy (SEM). Dental composite evaluation suggests a high thermal stability and inorganic content in RES D sample. Degrees of conversion (DC) values were almost the same and there was no direct relationship between DC and amount of particles and size. Similar compositions were found in all samples.

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Journal of Thermal Analysis and Calorimetry
Authors: Caroline Miyazaki, Igor Medeiros, Jivaldo Matos, and Leonardo Rodrigues Filho

Abstract  

Dental composites can be improved by heat treatment, as a possible way to increase mechanical properties due to additional cure (post-cure). Direct dental composites are essentially similar to the indirect ones, supposing they have the same indication. Therefore, to establish a heat treatment protocol for direct composites, using as indirect (photoactivated by continuous and pulse-delay techniques), a characterization (TG/DTG and DSC) is necessary to determine parameters, such as mass loss by thermal decomposition, heat of reaction and glass transition temperature (T g). By the results of this study, a heat treatment could be carried out above 160 °C (above T g, and even higher than the endset exothermic event) and under 180 °C (temperature of significant initial mass loss).

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Abstract  

The structural and thermal properties of three different dental composite resins, Filtek™ Supreme XT, Filtek™ Z-250 and TPH®3 were investigated in this study. The internal structures of uncured and cured resins with blue light-emitting diodes (LEDs) were examined by Micro-Raman spectroscopy. Thermal analysis techniques as DSC, TG and DTG methods were used to investigate the temperature characteristics, as glass transition (T g), degradation, and the thermal stability of the resins. The results showed that the TPH®3 and Filtek™ Supreme XT presented very similar T g values, 48 and 50°C, respectively, while the Filtek™ Z-250 composite resin presented a higher one, 58°C. AFM microscope was utilized in order to analyze the sample morphologies, which possess different fillers. The composed resin Filtek™ Z-250 has a well interconnected more homogeneous morphology, suggesting a better degree of conversion correlated to the glass phase transition temperature. The modes of vibration of interest in the resin were investigated using Raman spectroscopy. It was possible to observe the bands representative for the C=C (∼1630 cm−1) and C=O(∼1700 cm−1) vibrations were studied with respect to their compositions and polymerization. It was observed that the Filtek™ Z -250 resin presents the best result related to the thermal properties and polymerization after light curing among the other resins.

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Abstract  

We have investigated the thermal and structural properties of different commercial dental resins: FiltekTM Z-350, Grandio®, Tetric Ceram®, and TPH Spectrum®. The purpose of the present study was to evaluate quantitatively the photo-polymerization behavior and the effect of filler contents on the kinetic cures of the dental resins by using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. We have successfully obtained the low and high glass transition T g values of the dental composite resins from DSC curves. It was also observed a good agreement between the both T g values, activation energies from thermal degradation, and the degree of conversion obtained for all samples. The results have shown that Tetric Ceram® dental resin presented the higher T g values, activation energy of 215 ± 6 KJ mol−1, and the higher degree of conversion (63%) when compared to the other resins studied herein.

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Evaluation of different light-curing lamps

Halogen versus new-diode lamp

Journal of Thermal Analysis and Calorimetry
Authors: Maurizio Ferrante, Paolo Dottore, Morena Petrini, Paolo Trentini, and Giuseppe Spoto

restoration in posterior teeth and heterogeneity in the polymerization frequently are mentioned as drawbacks for the use of polymer restoration dental composites as repairing materials. Both problems are related to the curing process responsible for the

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polymer restoration dental composites as repairing materials. Both problems are related to the curing process responsible for the formation of the crosslinking network that provides mechanical resistance and hardness to the final composite [ 6 , 7

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Journal of Thermal Analysis and Calorimetry
Authors: S. X. S. Costa, M. R. Galvão, D. P. Jacomassi, M. I. B. Bernardi, A. C. Hernandes, A. N. de Souza Rastelli, and M. F. Andrade

commercial dental composite resins, used in this study, are summarized in Table 1 . Each represents one of two different categories of composites: microhybrid and nanocomposite. Table 1 Characteristics of restorative

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Orvosi Hetilap
Authors: Krisztina Mikulás, Mercedes Linninger, Emőke Takács, Barbara Kispélyi, Katalin Nagy, Pál Fejérdy, and Péter Hermann

–1005. 37 Polydorou O, König A, Hellwig E, et al. Long-term release of monomers from modern dental-composite materials. Eur J Oral Sci. 2009; 117: 68–75. 38 Klinke T

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Journal of Thermal Analysis and Calorimetry
Authors: Maurizio Ferrante, Paolo Trentini, Fausto Croce, Morena Petrini, and Giuseppe Spoto

, Mothé , CG 2009 Characterization of dental composites by thermal analysis, infrared spectroscopy and scanning electron microscopy . J Therm Anal Calorim 97 : 585 – 589 10.1007/s10973-009-0359-y . 12

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Journal of Thermal Analysis and Calorimetry
Authors: G. Scheltjens, J. Brancart, I. De Graeve, B. Van Mele, H. Terryn, and G. Van Assche

. Urabe , H , Wakasa , K , Yamaki , M . Application of multifunctional base monomer to dental composite resins . J Mater Sci Mater Med . 1990 ; 1 : 163 – 170 . 10.1007/BF00700877 . 2

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