IADR Abstract Archives
Interpenetrating Network Composites with Multifunctional Oxiranes and Acrylates
Objectives: To develop an Oxirane/Acrylate interpenetrating network composite System (OASys) using multifunctional oxiranes and acrylates to double restoration longevity.
Methods: Blends of multifunctional oxiranes (Epalloy8330 (3.3 functionality) or 8370 (3.7 functionality)) and a multifunctional acrylate (dipentaerythritol penta/hexaacrylate, DPHA) were filled with unsilanated glass to 60% or 70wt%. A 3-component initiator containing camphorquinone, 4'-methyldiphenyliodonium tetrakis(pentafluorophenyl) borate and hexamethylene diamine (HMDA) was optimized. Composites were tested for degree-of-cure (Rockwell15T hardness) and hydrophobicity (contact angle). Optimized systems were filled with acrylate and/or oxirane-silanated filler and tested mechanically in 3-point bending.
Results: Only the 25:75 Epalloy:DPHA composites cured well. At 60% fill with unsilanated filler, using Epalloy8370 instead of 8330 increased initial (~49 to ~59 RHN) and 24-hr hardness (~52 to ~68 RHN). Adding 0.75% HMDA to Epalloy8370-based OASys composites increased initial (~55 RHN; similar to the 70:30 BisGMA:TEGDMA control) and 24-hr hardness (~68 RHN). Filling to 70% with unsilanated filler increased control group 24-hr hardness (~68RHN) and OASys initial (~73 RHN) and 24-hr hardness (~76 RHN). Filling with oxirane-silanated filler did not improve hardness in controls and decreased OASys hardness (~66RHN). Filling with methacrylate-silanated filler increased control hardness (~68 RHN). Filling with acrylate-silanated filler further increased control and OASys hardness (~75 and ~80 RHN, respectively). Filling OASys composites with 25:75 oxirane:acrylate silanated filler produced ~76 RHN. Contact angle results showed no differences between groups. Mechanical results showed Epalloy8370-based OASys composites had slightly lower modulus and ultimate transverse strength compared to controls, despite having higher hardness. However, they had comparable energy-to-break.
Conclusions: An OASys composite with high degree-of-cure was developed using multifunctional oxiranes and acrylates. Increase in oxirane functionality, filler-loading, and use of acrylate-silanated filler, increases hardness. OASys composites are harder, as tough, and less brittle than controls, but not more hydrophobic. Other ways of increasing hydrophobicity are being explored.
Methods: Blends of multifunctional oxiranes (Epalloy8330 (3.3 functionality) or 8370 (3.7 functionality)) and a multifunctional acrylate (dipentaerythritol penta/hexaacrylate, DPHA) were filled with unsilanated glass to 60% or 70wt%. A 3-component initiator containing camphorquinone, 4'-methyldiphenyliodonium tetrakis(pentafluorophenyl) borate and hexamethylene diamine (HMDA) was optimized. Composites were tested for degree-of-cure (Rockwell15T hardness) and hydrophobicity (contact angle). Optimized systems were filled with acrylate and/or oxirane-silanated filler and tested mechanically in 3-point bending.
Results: Only the 25:75 Epalloy:DPHA composites cured well. At 60% fill with unsilanated filler, using Epalloy8370 instead of 8330 increased initial (~49 to ~59 RHN) and 24-hr hardness (~52 to ~68 RHN). Adding 0.75% HMDA to Epalloy8370-based OASys composites increased initial (~55 RHN; similar to the 70:30 BisGMA:TEGDMA control) and 24-hr hardness (~68 RHN). Filling to 70% with unsilanated filler increased control group 24-hr hardness (~68RHN) and OASys initial (~73 RHN) and 24-hr hardness (~76 RHN). Filling with oxirane-silanated filler did not improve hardness in controls and decreased OASys hardness (~66RHN). Filling with methacrylate-silanated filler increased control hardness (~68 RHN). Filling with acrylate-silanated filler further increased control and OASys hardness (~75 and ~80 RHN, respectively). Filling OASys composites with 25:75 oxirane:acrylate silanated filler produced ~76 RHN. Contact angle results showed no differences between groups. Mechanical results showed Epalloy8370-based OASys composites had slightly lower modulus and ultimate transverse strength compared to controls, despite having higher hardness. However, they had comparable energy-to-break.
Conclusions: An OASys composite with high degree-of-cure was developed using multifunctional oxiranes and acrylates. Increase in oxirane functionality, filler-loading, and use of acrylate-silanated filler, increases hardness. OASys composites are harder, as tough, and less brittle than controls, but not more hydrophobic. Other ways of increasing hydrophobicity are being explored.