Navegando por Autor "Galvão, M. R."
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Artigo Compressive strength of dental composites photo-activated with different light tips(2013) Galvão, M. R.; Caldas, Sergei Godeiro Fernandes Rabelo; Calabrez-Filho, S.; Campos, Edson Alves de; Bagnato, Vanderlei Salvador; Rastelli, A. N. S.; Andrade, Marcelo FerrareziThe aim of this study was to evaluate the compressive strength of microhybrid (FiltekTM Z250) and nanofilled (FiltekTM Supreme XT) composite resins photo-activated with two different light guide tips, fiber optic and polymer, coupled with one LED. The power density was 653 mW cm−2 when using the fiber optic light tip and 596 mW cm−2 with the polymer. After storage in distilled water at 37 ± 2 "C for seven days, the samples were subjected to mechanical testing of compressive strength in an EMIC universal mechanical testing machine with a load cell of 5 kN and speed of 0.5 mm min−1. The statistical analysis was performed using ANOVA with a confidence interval of 95% and Tamhane’s test. The results showed that the mean values of compressive strength were not influenced by the different light tips (p > 0.05). However, a statistical difference was observed (p < 0.001) between the microhybrid composite resin photo-activated with the fiber optic light tip and the nanofilled composite resin. Based on these results, it can be concluded that microhybrid composite resin photo-activated with the fiber optic light tip showed better results than nanofilled, regardless of the tip used, and the type of the light tip did not influence the compressive strength of either composite. Thus, the presented results suggest that both the fiber optic and polymer light guide tips provide adequate compressive strength to be used to make restorations. However, the fiber optic light tip associated with microhybrid composite resin may be an interesting option for restorations mainly in posterior teeth.Artigo Degree of conversion of different composite resins photo-activated with light-emitting diode and argon ion laser(2015) Messias, A. M.; Galvão, M. R.; Boaventura, J. M. C.; Jacomassi, D. P.; Bernardi, M. I. B.; Bagnato, Vanderlei Salvador; Rastelli, A. N. S.; Andrade, Marcelo FerrareziThis study evaluated the degree of conversion (DC%) of one experimental and different brands of composite resins light-cured by two light sources (one LED and one argon laser). The percentage of unreacted C = C was determined from the ratio of absorbance intensities of aliphatic C = C (peak at 1637 cm−1) against internal standards before and after curing: aromatic C–C (peak at 1610 cm−1) except for P90, where %C = C bonds was given for C–O–C (883 cm−1) and C–C (1257 cm−1). ANOVA and Tukey’s test revealed no statistically significant difference among Z350 (67.17), Z250 (69.52) and experimental (66.61 ± 2.03) with LED, just among them and Evolu-X (75.51) and P90 (32.05) that showed higher and lower DC%, respectively. For the argon laser, there were no differences among Z250 (70.67), Z350 (69.60), experimental (65.66) and Evolu-X (73, 37), however a significant difference was observed for P90 (36.80), which showed lowest DC%. The light sources showed similar DC%, however the main difference was observed regarding the composite resins. The lowest DC% was observed for the argon laser. P90 showed the lowest DC% for both light-curing sources.Artigo Evaluation of degree of conversion and hardness of dental composites photo-activated with different light guide tips(2013) Galvão, M. R.; Caldas, Sergei Godeiro Fernandes Rabelo; Bagnato, Vanderlei Salvador; Rastelli, Alessandra Nara de Souza; Andrade, Marcelo FerrareziObjective: The aim of this study was to evaluate the degree of conversion and hardness of different composite resins, photo-activated for 40 s with two different light guide tips, fiber optic and polymer. Methods: Five specimens were made for each group evaluated. The percentage of unreacted carbon double bonds (% C═C) was determined from the ratio of absorbance intensities of aliphatic C═C (peak at 1637 cm−1) against internal standard before and after curing of the specimen: aromatic C-C (peak at 1610 cm−1). The Vickers hardness measurements were performed in a universal testing machine. A 50 gf load was used and the indenter with a dwell time of 30 seconds. The degree of conversion and hardness mean values were analyzed separately by ANOVA and Tukey’s test, with a significance level set at 5%. Results: The mean values of degree of conversion for the polymer and fiber optic light guide tip were statistically different (P<.001). The hardness mean values were statistically different among the light guide tips (P<.001), but also there was difference between top and bottom surfaces (P<.001). Conclusions: The results showed that the resins photo-activated with the fiber optic light guide tip promoted higher values for degree of conversion and hardness.Artigo Sensitivity in Dental Bleaching and the Use of Anti-Inflammatory Agents(2014) Souza, Géssica Dandara Medeiros de; Santos, Letícia Mendes; Fernandes, Cleophatra Aquino; Dantas, Emanuelle Dayana Vieira; Galvão, M. R.; Assunção, Isauremi Vieira de; Borges, Boniek Castillo DutraThis study discusses the role of anti-inflammatory medications in reducing the sensitivity caused by tooth bleaching. Hydrogen peroxide (H2O2), the active principle in bleaching agents, reacts with dental enamel on contact and produces oxygen, in the form of free radicals, and water. Because of the low molecular weight of free radicals, as well as the porous nature and selective permeability of enamel, the free radicals pass into dentin and through the dentinal tubules, to the pulp. In response to these stimuli, defense cells in the pulp tissue promote the release of inflammatory mediators, resulting in short-term tooth sensitivity that may be experienced as acute pain. Anti-inflammatory medications will reduce the inflammatory response, as these drugs act on the production pathways of the mediators. Drugs such as ibuprofen and etoricoxib should be thus effective in reducing tooth sensitivity. Among the medications used, however, only ibuprofen seems to reduce tooth sensitivity from bleaching.