IADR Abstract Archives
Mechanical Performance of Photocured Thiol–Vinyl Sulfone Resin-based Dental Composites
Objectives: Evaluate the mechanical properties of a series of novel ester-free dental composite materials that are based on thiol–vinyl sulfone resins photopolymerized via free-radical thiol–ene chemistry and compare to those of BisGMA/TEGDMA (70/30) methacrylate control system cured in an analogous fashion.
Methods: Oligomerization of two multifunctional thiols – tetra(2-mercaptoethylene)-silane (SiTSH) and/or 1,2,3-tris(3-mercapto propylene)-1,3,5-triazyne-2,4,6-trion (TTTSH) with divinyl-sulfone (DVS) was performed by means of the base-initiated thiol–Michael addition reaction with triethylamine (TEA) and subsequently mixed with stoichiometric mole amounts of 1,3,5-triallyl-1,3,5-triazyne-2,4,6-trion (TATATO) with respect to functional groups, giving two different experimental resin formulations. 1 wt% of photoinitiator (Irgacure 819) was added to all the resin formulations. Dental composites were obtained by introducing 25 wt% of methacrylate-functionalized fillers (0.4 µm Ba glass) and crosslinked at ambient temperature with visible light (400–500 nm, 25 mW/cm2). Mechanical properties were measured using a standard 3-point bending test on three independent sample specimens.
Results: The mechanical properties of the composites are summarized in Table1. There was apparent improvement in the flexural strength and load at break of the novel resin-based materials as compared to the BisGMA/TEGDMA control system.
Conclusions: Novel ester-free resins were developed to serve as potential dental materials. The mechanical performance was apparently improved with respect to the control composite system indicating that these resins can serve as potential polymeric resins for restorative dental composite materials. The use of oligomers is expected to reduce the overall volumetric shrinkage, leading to lower polymerization shrinkage stress. The step-growth nature of the polymerization can also be expected to provide more homogeneous network structure with less elutable material compared to the dimethacrylate control.
Methods: Oligomerization of two multifunctional thiols – tetra(2-mercaptoethylene)-silane (SiTSH) and/or 1,2,3-tris(3-mercapto propylene)-1,3,5-triazyne-2,4,6-trion (TTTSH) with divinyl-sulfone (DVS) was performed by means of the base-initiated thiol–Michael addition reaction with triethylamine (TEA) and subsequently mixed with stoichiometric mole amounts of 1,3,5-triallyl-1,3,5-triazyne-2,4,6-trion (TATATO) with respect to functional groups, giving two different experimental resin formulations. 1 wt% of photoinitiator (Irgacure 819) was added to all the resin formulations. Dental composites were obtained by introducing 25 wt% of methacrylate-functionalized fillers (0.4 µm Ba glass) and crosslinked at ambient temperature with visible light (400–500 nm, 25 mW/cm2). Mechanical properties were measured using a standard 3-point bending test on three independent sample specimens.
Results: The mechanical properties of the composites are summarized in Table1. There was apparent improvement in the flexural strength and load at break of the novel resin-based materials as compared to the BisGMA/TEGDMA control system.
Conclusions: Novel ester-free resins were developed to serve as potential dental materials. The mechanical performance was apparently improved with respect to the control composite system indicating that these resins can serve as potential polymeric resins for restorative dental composite materials. The use of oligomers is expected to reduce the overall volumetric shrinkage, leading to lower polymerization shrinkage stress. The step-growth nature of the polymerization can also be expected to provide more homogeneous network structure with less elutable material compared to the dimethacrylate control.