Physicochemical properties of dental resins formulated with amine-free photoinitiation systems. Issue 9 (September 2021)

• Record Type: Journal Article
• Authors: Salvador, Marcos Vinícius; Fronza, Bruna M.; Pecorari, Vanessa Galego Arias; Ogliari, Fabrício A.; Braga, Roberto Ruggiero; Oxman, Joe D.; Lima, Adriano F.
• Is Part Of: Dental materials. Volume 37:Issue 9(2021)
• Page Start: 1358
• Page End: 1365
• Publication Date: 2021-09
• Subjects: Degree of conversion -- Mechanical properties -- Polymerisation -- Amine; Dentistry -- Periodicals; Dental materials -- Periodicals; 617.695
• DOI: 10.1016/j.dental.2021.06.005
• Languages: English
• ISSNs: 0109-5641

Abstract

Graphical abstract: Highlights: UDMA can work as an electron donor for free radical polymerisation systems. BIsGMA is an inadequate electron donor in the presence of camphorquinone without amine. Iodonium salts can improve the degree of conversion of amine-free systems. Abstract: Objective: To assess the mechanical properties of two different dimethacrylate resin blends containing the photosensitizer camphorquinone (CQ) alone or in combination with one or more synergists including an amine and/or an iodonium. Methods: Two co-monomer resin blends were formulated using Bis-GMA/TEGDMA and UDMA/TEGDMA, both at 1:1 mass ratio. Each resin blend was divided into four groups, comprising the following four photoinitiation systems: (1) CQ + 2-(dimethylamino)ethyl methacrylate (DMAEMA); (2) CQ + DMAEMA + bis(4-methyl phenyl)iodonium hexafluorophosphate (BPI); (3) CQ; and (4) CQ + BPI. Materials were evaluated for polymerisation kinetics, water sorption, solubility, flexural strength and modulus. Results: BisGMA/TEGDMA with CQ showed minimal and insignificant degree of conversion and was not tested for water sorption/solubility and mechanical properties. The ternary system (i.e., CQ + DMAEMA + BPI), promoted the highest degree of conversion for each monomer blend. The resins containing amine had higher mechanical properties than the amine free. However, the UDMA amine free resins exhibited greater flexural strength and modulus than the corresponding amine free BisGMA resins. BisGMA/TEGDMA containing CQ + DMAEMA or CQ + BPI had significantly higher water sorption and solubility than the other groups. Significance: Resins containing amine presented better properties than the amine-free systems. The addition of iodonium salt (BPI) improved the degree of conversion of the resins, even without an amine co-initiator. The amine-free initiator system (CQ + BPI) was more effective when used with UDMA versus BisGMA based-resins respectively.