Degree of conversion of nanofilled and microhybrid composite resins photo-activated by different generations of LEDs

• Autor(a) principal: Ribeiro, Benicia Carolina Iaskieviscz
• Data de Publicação: 2012
• Outros Autores: Boaventura, Juliana Maria Capelozza, Brito-Gonçalves, Joel de, Rastelli, Alessandra Nara de Souza, Bagnato, Vanderlei Salvador, Saad, José Roberto Cury
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of applied oral science (Online)
• DOI: 10.1590/S1678-77572012000200015
• Texto Completo: https://www.revistas.usp.br/jaos/article/view/46222
• topic: Composite resins; Fourier transform infrared spectroscopy; Nanotechnology; Light

OBJECTIVE:This study aimed at evaluating the degree of conversion (DC) of four composite resins, being one nanofilled and 3 microhybrid resins, photo-activated with second- and third-generation light-emitting diodes (LEDs). MATERIAL AND METHODS: Filtek TM Z350 nanofilled composite resins and Amelogen® Plus, Vit-l-escenceTM and Opallis microhybrid resins were photo-activated with two second-generation LEDs (Radii-cal and Elipar Free LightTM 2) and one third-generation LED (Ultra-Lume LED 5) by continuous light mode, and a quartz halogen-tungsten bulb (QHT, control). After 24 h of storage, the samples were pulverized into fine powder and 5 mg of each material were mixed with 100 mg of potassium bromide (KBr). After homogenization, they were pressed, which resulted in a pellet that was evaluated using an infrared spectromer (Nexus 470, Thermo Nicolet) equipped with TGS detector using diffuse reflectance (32 scans, resolution of 4 cm-1) coupled to a computer. The percentage of unreacted carbon-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). RESULTS: The ANOVA showed a significant effect on the interaction between the light-curing units (LCUs) and the composite resins (p