title: Influence of polymerization initiator for base monomer on microwave curing of composite resin inlays.
abstract: Microwave polymerization was used to make composite resin inlays and the effect examined of the concentration of polymerization initiator for the base monomer. The monomers used were 2,2-bis [4-(3-methacriloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). Bis-GMA and TEGDMA were mixed in a ratio of 6:4 by weight and were separated into five groups. To each group was added benzoyl peroxide (BPO) in the ratios of 0.1, 0.3, 0.5, 0.7 and 0.9 wt% as the polymerization initiator. These were used as the base monomers. The results showed that the degree of conversion of the cured sample increased with increasing concentration of BPO from 0.1 to 0.5 wt%, however there was no significant difference at 0.5, 0.7 and 0.9 wt% (P> 0.01). Compression strength, diametral tensile strength and the Knoop hardness showed a similar tendency as the degree of conversion. No significant difference was recorded in the Knoop hardness between the top and the bottom surfaces (P> 0.01), which suggested a uniform polymerization in the cured sample. Thus, microwave polymerization would be an efficacious method for making resin inlays with the addition of BPO to the base monomer (Bis-GMA:TEGDMA, 6:4). The maximum conversion was found at a concentration of 0.5 wt%.
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Hiroshima University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Urabe
authors.forename: Y
authors.initials: Y
authors.lastname: Nomura
authors.forename: K
authors.initials: K
authors.lastname: Shirai
authors.forename: M
authors.initials: M
authors.lastname: Yoshioka
authors.forename: H
authors.initials: H
authors.lastname: Shintani
mesh_terms: D001585:Benzoyl Peroxide / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003188:Composite Resins / Q000737:chemistry*; D019245:Compressive Strength; D006244:Hardness; D007284:Inlays; D008422:Materials Testing; D008872:Microwaves; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D011108:Polymers; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D001585:Benzoyl Peroxide