Quantitative analysis of TEGDMA and HEMA eluted into saliva from two dental composites by use of GC/MS and tailor-made internal standards.
OBJECTIVE
The use of resin-based dental restorative materials is rapidly increasing, concurrently the biocompatibility of the materials is under investigation. Attention has been placed on studies addressing the cytotoxic, genotoxic and estrogenic potential of these materials. Therefore, the degree of exposure to eluted compounds from the dental materials is of high interest. The aim of this study was to assess the amounts of 2-hydroxyethyl methacrylate (HEMA) and triethyleneglycol dimethacrylate (TEGDMA), released from two composites, eluting into human saliva. To improve the method of quantification, three tailor-made internal standards were synthesized.


METHODS
Specimens made from two composites (Tetric EvoCeram and Filtek Z250) were polymerized and immersed in human saliva for 24h. Eluted TEGDMA and HEMA were identified and quantified. The quantitative analyses were performed by use of combined gas chromatography-mass spectrometry (GC/MS) with tailor-made internal standards synthesized by dissolving HEMA or TEGDMA in methanol and reducing the double bond of the methacrylate group by hydrogenation with 1H2 and 2H2 (D2) gas.


RESULTS
HEMA was released from both materials, whereas TEGDMA eluted from Filtek Z250 only. Full scan GC-MS analysis of each tailor-made internal standard demonstrated one peak only, which was well separated from the corresponding analyte's peak and with no traces of HEMA or TEGDMA.


CONCLUSIONS
The quantification method seems well suited for in vivo analysis, and the three standards synthesized represent an improved tool for quantification of the eluted monomers. The synthesis may be applied to other methacrylate monomers to produce tailor-made standards for quantification.
Michelsen
Vibeke B
VB
Department of Oral Sciences--Cariology, Faculty of Dentistry, University of Bergen, Armauer Hansens Hus, 5021 Bergen, Norway. vibeke.michelsen@odont.uib.no
Moe
Grete
G
Strøm
Morten B
MB
Jensen
Einar
E
Lygre
Henning
H
D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D004058:Diffusion; D008401:Gas Chromatography-Mass Spectrometry / Q000592:standards; D006801:Humans; D006865:Hydrogenation; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012015:Reference Standards; D012463:Saliva / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013997:Time Factors
D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D008689:Methacrylates; D011109:Polymethacrylic Acids; D012997:Solvents; C501891:Tetric EvoCeram; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; C005044:hydroxyethyl methacrylate; D000432:Methanol