title: Synthesis of iodine-containing cyclophosphazenes for using as radiopacifiers in dental composite resin.
abstract: In this study, a strategy of using iodine-containing cyclophosphazenes as radiopacifiers for dental composite resin was evaluated. It was hypothesized that cyclophosphazenes bearing both iodine and acrylate group swere able to endow composite resins radiopacity without compromising mechanical properties. The cyclophosphazene compounds were synthesized by subsequently nucleophilic substitution of hexachlorocyclotriphosphazene with hydroxyethyl methacrylate (HEMA) and 4-iodoaniline. Cyclotriphosphazenes containing two different molar ratios of HEMA to 4-iodoaniline (1:5 and 2:4) were obtained, and were identified with (1)H NMR, FT-IR, UV and mass spectroscopy. The iodine-containing cyclophosphazenes were able to dissolve well in bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin, and were added at two contents (10 or 15%wt. of the resin). The resins were photo-cured and post-thermal treated before characterizations. The resulting composite resins demonstrated the ability of blocking X-ray. And the addition of HEMA-co-iodoaniline substituted cyclotriphosphazenes caused minor adverse effect on the mechanical properties of the resins because the cyclotriphosphazenes could mix well and react with the resins. The presence of rigid phosphazene rings between resin backbones displayed an effective function of decreasing polymerization shrinkage. In summary, soluble and reactive iodine-containing cyclotriphosphazenes demonstrated advantages over traditional heavy metals or metal oxides in being used as additives for producing radiopaque dental resins.
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Jinle
authors.initials: J
authors.lastname: Lan
authors.affiliation: Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, PR China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, PR China.
authors.forename: Xuliang
authors.initials: X
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, PR China; Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: caiqing@mail.buct.edu.cn.
authors.forename: Qing
authors.initials: Q
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, PR China; Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yang
mesh_terms: D007455:Iodine / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D066244:Proton Magnetic Resonance Spectroscopy; D012117:Resins, Synthetic; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D009943:Organophosphorus Compounds; D012117:Resins, Synthetic; C074235:cyclophosphazene monomer; D007455:Iodine
keywords: Composite resin; Cyclophosphazene; Iodine; Radiopaque