RESUMO
OBJECTIVE: To evaluate the degree of conversion (DC), flexural strength (FS) and Knoop microhardness (KHN) of direct and indirect composite resins polymerized with different curing systems. MATERIALS AND METHODS: Specimens of direct (Z250, 3M/Espe) and indirect (Sinfony, 3M/Espe) restorative materials were made and polymerized using two light curing units: XL2500 (3M/Espe) and Visio system (3M/Espe). Absorption spectra of both composites were obtained on a FTIR spectrometer in order to calculate the DC. FS was evaluated in a universal testing machine and surface microhardness was performed in a microhardness tester (50gf/15s). DC, FS and KHN data were submitted to two-way ANOVA and Tukey's test (α = 0.05). RESULTS: Z250 showed higher DC, FS and KHN compared with Sinfony when the polymerization was carried out with XL2500 (p < 0.05). However, there is no statistical difference in DC between the materials when Visio was used (p > 0.05). Visio showed higher DC and KHN for Z250 and Sinfony than the values obtained using XL2500 light curing (p < 0.05). For FS, no significant difference between curing units was found (p > 0.05). CONCLUSION: Even though the Visio system could increase DC and KHN for some direct and indirect composites, compared with the conventional halogen curing unit, a high number of monomers did not undergo conversion during the polymerization.
Assuntos
Resinas Compostas , Luzes de Cura Dentária , Teste de Materiais , Análise de VariânciaRESUMO
O objetivo do trabalho foi avaliar o grau de conversão de três resinas compostas fotoativadas (Fill Magic, TPH Spectrum e Te-Econom). Cento e vinte amostras foram preparadas, as quais foram irradiadas por 20 e 40s usando quatro fontes diferentes (duas halógenas e duas à base de LED). O grau de conversão foi avaliado a partir de dados de absorção no infravermelho próximo obtidos em um espectrofotômetro infravermelho. Os resultados mostram que o grau de conversão aumenta com o tempo de irradiação somente quando as resinas foram irradiadas com fontes de luz com densidade de potência menor do que 233 mW/cm2. Todas as três resinas alcançaram o nível de conversão tipicamente observado em resinas fotoativadas comerciais.
Assuntos
Fenômenos Físicos , Resinas Compostas/efeitos da radiação , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree.
Assuntos
Resinas Compostas/química , Materiais Dentários/química , Espectroscopia de Infravermelho com Transformada de Fourier , Absorção , Algoritmos , Calibragem , Carbono/química , Fenômenos Químicos , Humanos , Metacrilatos/química , Metilmetacrilato/química , Fenômenos Ópticos , Polímeros/química , Polimetil Metacrilato/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/normasRESUMO
Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree.
