IADR Abstract Archives
High Refractive Index and HIgh Viscosity Dental Monomer
Objectives: BisGMA has long been utilized in dental composite formulations but has recently attracted attention due to possible residual BisPhenol A based complications. As an intial target, a BisGMA replacement must be able to be formulated to match the refractive index (1.521) the viscosity (276.8 cps at 40°C) of a 70% BisGMA/30% TEGDMA blend.
Methods: A blend of methylene diphenylisocyanates and a blend of 2-hydroxyethyl methacrylate and hydroxypropyl methacrylate were reacted to give a liquid urethane product mixture. The monomer was blended with TEGDMA (68/32 by weight) This blend was cured either photchemically with camphorquinone and ethyl 4-dimethylaminobenzoate or thremally with benzoyl peroxide to compare to the bisGMA/TEGDMA blend cured under the same conditions.
Results: A 70% BisGMA/30% TEGDMA blend has a refractive index (1.521) the viscosity of 276.8 cps (40°C) and the MDI monomer (68%) blend with TEGDMA (32%) has an RI of 1.522 and a viscosity of 417 cps (40°C). Photochemically cured Tg (180.25 +/-2.3°C, n=5) and Young’s modulus (2.31 +/- 0.4 GPa, n=5) for the MDI adduct compares to BisGMA/TEGDMA (135.3 +/-5.3, n=5; and 2.32 +/- 0.35, n=5). Thermally cured Tg (179.5 +/-2.5°C, n=5) and Young’s modulus (3.22 +/- 0.17 GPa, n=5) for the MDI adduct compares to BisGMA/TEGDMA (170.39 +/- 2.87, n=5; and 3.12 +/- 0.26, n=5).
Conclusions: The MDI adduct could be utilized as a replacement for BisGMA in composite formulations.
Methods: A blend of methylene diphenylisocyanates and a blend of 2-hydroxyethyl methacrylate and hydroxypropyl methacrylate were reacted to give a liquid urethane product mixture. The monomer was blended with TEGDMA (68/32 by weight) This blend was cured either photchemically with camphorquinone and ethyl 4-dimethylaminobenzoate or thremally with benzoyl peroxide to compare to the bisGMA/TEGDMA blend cured under the same conditions.
Results: A 70% BisGMA/30% TEGDMA blend has a refractive index (1.521) the viscosity of 276.8 cps (40°C) and the MDI monomer (68%) blend with TEGDMA (32%) has an RI of 1.522 and a viscosity of 417 cps (40°C). Photochemically cured Tg (180.25 +/-2.3°C, n=5) and Young’s modulus (2.31 +/- 0.4 GPa, n=5) for the MDI adduct compares to BisGMA/TEGDMA (135.3 +/-5.3, n=5; and 2.32 +/- 0.35, n=5). Thermally cured Tg (179.5 +/-2.5°C, n=5) and Young’s modulus (3.22 +/- 0.17 GPa, n=5) for the MDI adduct compares to BisGMA/TEGDMA (170.39 +/- 2.87, n=5; and 3.12 +/- 0.26, n=5).
Conclusions: The MDI adduct could be utilized as a replacement for BisGMA in composite formulations.