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Title: Influence of energy density of different light sources on knoop hardness of a dual cured resin cement
Authors: Piva, Evandro
Correr Sobrinho, Lourenço
Sinhoreti, Mário Alexandre Coelho
Consani, Simonides
Demarco, Flávio Fernando
Powers, John Michel
Abstract: The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated withdifferent light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs) were tested: tungsten halogen light (HAL), light-emitting diode (LED) and xenon plasma-arc (PAC) lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce). Three energy doses were used by modifying the irradiance (I) of each LCU and the irradiation time (T): 24 Jcm-2 (I/2x2T), 24 Jcm-2 (IxT) and 48 Jcm-2 (Ix2T). Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus). Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10). Knoop hardness number (KHN) means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (α=5%). Application of 48 energy dose through the ceramic using LED (50.5±2.8)and HAL (50.9±3.7) produced significantly higher KHN means (p<0.05) than the control (44.7±3.8). LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.
Keywords: Hardness test
Resin cements
Dental materials
Publisher: University of São Paulo
Citation: Piva, Evandro ; Correr Sobrinho, Lourenço ; SINHORETI, Mario Alexandre Coelho ; CONSANI, Simonides ; DEMARCO, Flávio Fernando ; Powers, John Michael . Influence of energy density of different light sources on knoop hardness of a dual-cured resin cement. Journal of Applied Oral Science, v. 16, p. 189-193, 2008
Issue Date: 28-Feb-2008
Appears in Collections:Departamento de Odontologia Restauradora: Artigos de periódicos

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