IADR Abstract Archives
Polymerization color change of commercial resin composites with different photoinitiators
Objectives: Camphorquinone (CQ) is the most commonly used photoinitiator in light-cured dental resin composites (RC). However, it is associated with a yellowing of the composite, which has led manufacturers to add alternative initiators into RCs to reduce the amount of CQ used. The objective of this study was to investigate the color change upon polymerization of commercial bulk-fill and traditional RCs with alternative photoinitiator systems.
Methods: Seven commercial RCs, including two bulk-fill RCs with CQ only (bulk CQ; Beautifil (Shofu) and SonicFill 2 (Kerr)), one bulk-fill RC with CQ plus additional initiator (bulk CQ+; Tetric EvoCeram Bulk Fill (Ivoclar Vivadent), one traditional RC with CQ only (traditional CQ; Heliomolar (Ivoclar)) and three traditional RCs with CQ plus additional initiator (traditional CQ+; Tetric EvoCeram (Ivoclar), Aelite LS Posterior (Bisco), and Vit-l-escence (Ultradent)) were tested. Eight specimens for each material were prepared with Teflon disc molds (7 mm diameter x 2 mm thickness) and light cured for 40 seconds with a quartz-tungsten-halogen light-curing unit. Color measurements were obtained with a spectrophotometer before and after polymerization. Color change was calculated using the formula: ΔE={(ΔL)2 + (Δa)2 + (Δb)2 }1/2. One way ANOVA and a post-hoc LSD test was conducted for statistical analysis.
Results: The color changes after polymerization ΔE (mean±SD) were 5.67±0.29 and 7.49±0.52 for the two bulk CQ, 11.81±0.47 for the bulk CQ+, 4.30±0.43 for the traditional CQ and 4.85±0.51, 6.70±0.26 and 7.42±0.58 for the three traditional CQ+. The color change of the bulk CQ+ was significantly (p<0.05) greater than the ΔE of both bulk CQ materials. All three traditional CQ+ showed significantly (p<0.05) greater color change than that of the traditional CQ resin composite.
Conclusions: RCs with CQ and additional photoinitiators have greater color change with polymerization than RCs with only CQ.
Methods: Seven commercial RCs, including two bulk-fill RCs with CQ only (bulk CQ; Beautifil (Shofu) and SonicFill 2 (Kerr)), one bulk-fill RC with CQ plus additional initiator (bulk CQ+; Tetric EvoCeram Bulk Fill (Ivoclar Vivadent), one traditional RC with CQ only (traditional CQ; Heliomolar (Ivoclar)) and three traditional RCs with CQ plus additional initiator (traditional CQ+; Tetric EvoCeram (Ivoclar), Aelite LS Posterior (Bisco), and Vit-l-escence (Ultradent)) were tested. Eight specimens for each material were prepared with Teflon disc molds (7 mm diameter x 2 mm thickness) and light cured for 40 seconds with a quartz-tungsten-halogen light-curing unit. Color measurements were obtained with a spectrophotometer before and after polymerization. Color change was calculated using the formula: ΔE={(ΔL)2 + (Δa)2 + (Δb)2 }1/2. One way ANOVA and a post-hoc LSD test was conducted for statistical analysis.
Results: The color changes after polymerization ΔE (mean±SD) were 5.67±0.29 and 7.49±0.52 for the two bulk CQ, 11.81±0.47 for the bulk CQ+, 4.30±0.43 for the traditional CQ and 4.85±0.51, 6.70±0.26 and 7.42±0.58 for the three traditional CQ+. The color change of the bulk CQ+ was significantly (p<0.05) greater than the ΔE of both bulk CQ materials. All three traditional CQ+ showed significantly (p<0.05) greater color change than that of the traditional CQ resin composite.
Conclusions: RCs with CQ and additional photoinitiators have greater color change with polymerization than RCs with only CQ.