Effect of dentine on release of TEGDMA from resin composite in vitro.
Triethylene glycol dimethacrylate (TEGDMA) is a component of some resin composites which contributes to their cytotoxicity. The presence of dentine between resin composite and test cells reduces the cytotoxicity in vitro. To determine why dentine has this protective effect, the diffusion of TEGDMA from a composite resin through dentine to the pulp space was compared with release directly into aqueous solution in vitro. Both release rate and total cumulative release of TEGDMA for the two groups, at times up to 100 days, were determined using reversed-phase HPLC. Release rate directly into water was highest in the minutes immediately after immersion and declined thereafter. However, in the tooth model, using an equivalent mass and surface area of composite resin, no TEGDMA was detectable in the pulp space until 43 min after restoration placement. The rate of diffusion through dentine from that time until day 1 was less than 1% of the highest (initial) direct release rate. The rate declined thereafter. It is relevant, however, that by day 3 the total cumulative release of TEGDMA through dentine was 60% of the direct release. Dentine therefore appears to exert its protective effect principally by retarding or 'damping' the initial high release of TEGDMA to a substantial degree.
Department of Restorative Dentistry, University of California, San Francisco 94143-0758.
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D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000633:toxicity*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D003804:Dentin / Q000378:metabolism*; D003806:Dentin Permeability; D004058:Diffusion; D006801:Humans; D011092:Polyethylene Glycols / Q000737:chemistry / Q000493:pharmacokinetics*; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000493:pharmacokinetics*; D013997:Time Factors; D014867:Water
C090257:Foundation composite resin; D011109:Polymethacrylic Acids; D014867:Water; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate