Lucas Casemiro | Jjjj 1 (original) (raw)

Lucas Casemiro

Uploads

Papers by Lucas Casemiro

Materials Research-ibero-american Journal of Materials, 2007

The purpose of this study was to assess the radiopacity and microhardness of different types of r... more The purpose of this study was to assess the radiopacity and microhardness of different types of resin-based composites (RBC hybrid; microhybrid; flowable; cement and polyacid modified) before and after being submitted to artificial accelerated aging. Fifty specimens (7 mm in diameter and 2 mm thick) were fabricated, 10 for each material. The specimens were light-cured and submitted to radiopacity and microhardness tests. After obtaining initial radiopacity and microhardness values, the specimens were taken to the artificial accelerated aging, and new measurement of radiopacity and microhardness of the samples was performed. Data were submitted to statistical analysis (Student's t-test p < 0.05). None of the materials studied showed changes in radiopacity after artificial accelerated aging. There was a significant decrease in microhardness for the microhybrid and polyacid-modified RBC´s. This study suggests that radiopacity remains unaltered after materials are submitted to artificial accelerated aging. Microhardness, however, may vary due to plasticization of the aged RBC matrix.

Esse trabalho apresentou nova metodologia para avaliar a liberação dinâmica de flúor de três mate... more Esse trabalho apresentou nova metodologia para avaliar a liberação dinâmica de flúor de três materiais, um cimento de ionômero de vidro restaurador (Vidrion R), um ionômero de vidro modificado por resina (Vitremer) e um compômero (Dyract AP). Após manipulação dos materiais segundo recomendações dos fabricantes e da obtenção dos corpos-deprova, os mesmos foram armazenados em saliva artificial sem flúor por 30 dias. A concentração de fluoreto nas soluções estoque foram determinadas com um potenciômetro, utilizando um eletrodo íon seletivo para fluoreto (Orion n o 9609 BN) conectado a um registrador (HANNA Instruments HI n o 9321). Os resultados indicaram um melhor comportamento do ionômero de vidro convencional, seguido do ionômero modificado e posteriormente do compômero. * Trabalho de conclusão do curso de odontologia da UNIFRAN. 009_UNESP out_dez.indd 55 3/5/08 4:10:34 PM Pires-de-Souza FCP, Zaroni AWA, Garcia LFRoberti, Cruvinel DR, Casemiro LA NOVA METODOLOgIA PARA ANáLISE COMPARATIVA DA LIBERAçãO DE FLúOR DE CIMENTOS DE IONôMERO DE VIDRO RESTAURADORES E COMPôMEROS Cienc Odontol Bras 2007 out./dez.; 10 (4): 55-60

Journal of Prosthetic Dentistry, 2009

The results of this in vitro study suggest that the number of firings of the all-ceramic material... more The results of this in vitro study suggest that the number of firings of the all-ceramic material evaluated may likely affect the color of definitive restorations.

Brazilian Dental Journal, 2009

The purpose of this study was to compare the polymerization shrinkage stress of composite resins ... more The purpose of this study was to compare the polymerization shrinkage stress of composite resins (microfilled, microhybrid and hybrid) photoactivated by quartz-tungsten halogen light (QTH) and light-emitting diode (LED). Glass rods (5.0 mm x 5.0 cm) were fabricated and had one of the surfaces air-abraded with aluminum oxide and coated with a layer of an adhesive system, which was photoactivated with the QTH unit. The glass rods were vertically assembled, in pairs, to a universal testing machine and the composites were applied to the lower rod. The upper rod was placed closer, at 2 mm, and an extensometer was attached to the rods. The 20 composites were polymerized by either QTH (n=10) or LED (n=10) curing units. Polymerization was carried out using 2 devices positioned in opposite sides, which were simultaneously activated for 40 s. Shrinkage stress was analyzed twice: shortly after polymerization (t40s) and 10 min later (t10min). Data were analyzed statistically by 2-way ANOVA and Tukey's test (a=5%). The shrinkage stress for all composites was higher at t10min than at t40s, regardless of the activation source. Microfilled composite resins showed lower shrinkage stress values compared to the other composite resins. For the hybrid and microhybrid composite resins, the light source had no influence on the shrinkage stress, except for microfilled composite at t10min. It may be concluded that the composition of composite resins is the factor with the strongest influence on shrinkage stress.