Avaliação do grau de conversão e microdureza Knoop de compositos odontologicos fotoativados por fontes de luz emitida por diodos / Evaluation of the degree of conversion and knoop hardness of composites light-cured by LED light curing units

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The purpose of this study was to evaluate and correlate the degree of conversion (DC) using Fourier-Transform Raman Spectroscopy (FT-R) and the Knoop Hardness (KHN) of composites cured by second and third generation light emitting diodes (LEDs) light curing units (LCU), Radii Cal (SDI Limited) and Ultralume 5 (Ultradent), respectively. Three composites - Filtek Supreme XT and Filtek Z350 (3M ESPE), and Esthet X (Dentsply) - were selected for this study. For KHN (n=10), the specimens were prepared in metallic mold (5mm X 2mm), in one increment, and lightcured according to the experimental groups. KHN was performed with 10g load for 10 seconds, with 10 indentations for top (T) and bottom (B) surfaces. For FT-R (n=10), the samples were prepared in metallic mold (7mm X 2mm) in the same manner for KHN and both T and B surfaces were analyzed. The data were submitted to ANOVA and Tukey test (5%). For KHN, the three composites differ in hardness and there was a double interaction “LCU versus surface” which Radii Cal showed the higher hardness in B surface, with statistical significant difference to the others. For FT-R, there was a “composite versus surface versus LCU” triple interaction. For “composite” factor, there was no significant difference between the groups, except for Filtek Supreme lightcured by Radii Cal either on T and B surfaces. For “LCU” factor there was a significant difference for Supreme XT T surface, where Ultralume 5 obtained higher DC. For Z350 T surface, significant difference in DC was also noticed where Radii Cal obtained better results. For “surface” factor, all groups presented T surface with higher DC than B surface, except Esthet X lightcured by Radii Cal and Filtek Z350 lightcured by Ultralume 5. The the knowledge of composites composition and the characteristics of LCUs are important to perform an effective polymerization. There was no correlation between direct and indirect methods in most of studied conditions.

ASSUNTO(S)

polymers spectrum analysis raman polimeros surface properties dental materials propriedades de superficie analise espectral raman materiais dentários

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