Effect of diphenyliodonium hexafluorophosphate on the physical and chemical properties of ethanolic solvated resins containing camphorquinone and 1-phenyl-1,2-propanedione sensitizers as initiators

• DPI can be used to improve properties of resins containing CQ and PPD as sensitizers.
• Formulations with PPD plus CQ and DPI showed the best chemical–physical properties.
• Combination of initiators can be an important means of improving properties of resins.

ObjectivesTo evaluate the effects of the diphenyliodonium hexafluorophosphate (DPI) on the physical and mechanical properties of solvated dental adhesive resins containing camphorquinone (CQ) and/or 1-phenyl-1,2-propanedione (PPD) as initiators.MethodsModel solvated resins containing bisphenol glycidyl methacrylate (BisGMA); triethyleneglycol dimethacrylate (TEGDMA); 1,3-glycerol dimethacrylate (GDMA); 2-hydroxyethyl methacrylate (HEMA); dimethylaminoethyl amine benzoate (EDAB) and ethanol were prepared. The resins were divided in 24 test groups according to the incorporated initiator systems (CQ-0.5 or 1 mol%; PPD-0.5 or 1 mol%; CQ + PPD-0.5 or 1 mol%) as well the presence of DPI (0, 0.5 or 1 mol%). Degree of conversion (using Fourier-transformed near infra-red spectroscopy), flexural strength and modulus by three point bending, cohesive strength and water sorption and solubility were measured. Data were statistically analyzed by one and two way ANOVA and Tukey's test (α = 0.05).ResultsDPI increased the degree of conversion of all materials tested. Camphorquinone promoted higher degree of conversion than resins containing only PPD or CQ + PPD. Generally, the resins containing PPD + CQ with DPI presented higher flexural strength and modulus, cohesive strength, as well lower water sorption and solubility.SignificanceThe use of PPD combined with CQ can increase the physical properties of the solvated resins. DPI improved the monomer conversion of all experimental materials and can positively modulate most of the physical properties of the solvated resins.