Dayane Carvalho Ramos Salles de Oliveira1, Mateus Garcia Rocha2, Ivo Carlos Correa3, Américo Bortolazzo Correr4, Jack L Ferracane5, Mario Alexandre Coelho Sinhoreti4. 1. Department of Biomaterials, School of Dentistry, Oregon Health & Science University, 2730 SW Moody Avenue, 27201 Portland, OR, USA; Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Av. Limeira, 900, 13414-903 Piracicaba, SP, Brazil. Electronic address: oliveira.day@icloud.com. 2. Department of Biomaterials, School of Dentistry, Oregon Health & Science University, 2730 SW Moody Avenue, 27201 Portland, OR, USA; Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Av. Limeira, 900, 13414-903 Piracicaba, SP, Brazil. 3. Department of Prosthesis and Dental Materials, School of Dentistry, Federal University of Rio de Janeiro, Avenida Brigadeiro Trompowski, s/n(o), Ilha do Fundão, Cidade Universitária, 21949-900 Rio de Janeiro, RJ, Brazil. 4. Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Av. Limeira, 900, 13414-903 Piracicaba, SP, Brazil. 5. Department of Biomaterials, School of Dentistry, Oregon Health & Science University, 2730 SW Moody Avenue, 27201 Portland, OR, USA.
Abstract
OBJECTIVE: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the color and curing profile of resin-based composites. METHODS: Experimental composites were produced with different CQ and TPO molar concentrations: CQ-only, 3CQ:1TPO, 1CQ:1TPO, 1CQ:3TPO, and TPO-only. Polywave LED was characterized using a beam profiler. Block-shaped samples (5mm×5mm×3mm depth) were cured in a custom-designed mold with a polywave LED positioned to compare the regions exposed to the 420-495nm and 380-420nm LED emittances. To map the cure profile, degree of conversion (DC) of longitudinal cross-sections from each block were evaluated by FT-NIR. Color, light-transmittance and light-absorption during curing were evaluated on specimens 1-3mm thick. Data were analyzed using ANOVA/Tukey's test (α=0.05; β=0.2). RESULTS: Though the polywave LED beam profile was non-uniform, up to a depth of 2mm no differences in DC were found among the composites containing CQ with TPO added up to 50%, regardless of the position under the curing tip. Composites with higher TPO concentration showed a decrease in DC beginning with a depth of 1mm, while composites with higher or similar CQ concentrations did not show decreased DC until a depth of 3mm. Higher TPO concentration reduced initial yellowness and color change after curing; and lower CQ concentration decreased light-absorption at greater depths. SIGNIFICANCE: The combination of CQ with TPO added up to 50% reduced the yellowness and color change of composites after curing without affecting cure efficiency up to a depth of 2mm.
OBJECTIVE: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the color and curing profile of resin-based composites. METHODS: Experimental composites were produced with different CQ and TPO molar concentrations: CQ-only, 3CQ:1TPO, 1CQ:1TPO, 1CQ:3TPO, and TPO-only. Polywave LED was characterized using a beam profiler. Block-shaped samples (5mm×5mm×3mm depth) were cured in a custom-designed mold with a polywave LED positioned to compare the regions exposed to the 420-495nm and 380-420nm LED emittances. To map the cure profile, degree of conversion (DC) of longitudinal cross-sections from each block were evaluated by FT-NIR. Color, light-transmittance and light-absorption during curing were evaluated on specimens 1-3mm thick. Data were analyzed using ANOVA/Tukey's test (α=0.05; β=0.2). RESULTS: Though the polywave LED beam profile was non-uniform, up to a depth of 2mm no differences in DC were found among the composites containing CQ with TPO added up to 50%, regardless of the position under the curing tip. Composites with higher TPO concentration showed a decrease in DC beginning with a depth of 1mm, while composites with higher or similar CQ concentrations did not show decreased DC until a depth of 3mm. Higher TPO concentration reduced initial yellowness and color change after curing; and lower CQ concentration decreased light-absorption at greater depths. SIGNIFICANCE: The combination of CQ with TPO added up to 50% reduced the yellowness and color change of composites after curing without affecting cure efficiency up to a depth of 2mm.