title: Relationship between the degree of conversion and internal discoloration of light-activated composite.
abstract: In order to elucidate the relationship between the degree of conversion and internal discoloration of light-activated composite, four experimental composites which contained different amounts of Bis-GMA and TEGDMA were prepared, and the degree of conversion and discoloration of each composite, with or without annealing, were determined. The degree of conversion was measured by Fourier transformation infrared spectroscopy and the color change was determined after 1, 2, 3 and 4 weeks of immersion in water at 60 degrees C. The non-annealed composites demonstrated a greater degree of conversion and less discoloration as the amount of TEGDMA was increased. Annealed composites showed a significantly greater degree of conversion and less discoloration compared with the non-annealed composites. The results indicate that the greater the degree of conversion, the less the discoloration of composite, and the correlation between the two factors was significant for light-activated composite.
authors.affiliation: Department of Operative Dentistry, Osaka University Faculty of Dentistry, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Imazato
authors.forename: H
authors.initials: H
authors.lastname: Tarumi
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: H
authors.initials: H
authors.lastname: Hiraguri
authors.forename: K
authors.initials: K
authors.lastname: Oda
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuchitani
mesh_terms: D000588:Amines / Q000737:chemistry; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002863:Chromogenic Compounds / Q000737:chemistry*; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry; D008027:Light; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000588:Amines; D002863:Chromogenic Compounds; D003188:Composite Resins; D005030:Ethylenes; D011108:Polymers; D011109:Polymethacrylic Acids; D014867:Water; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate