| 3247 Identification of Compounds Leached from Dental Core Materials | ||
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J.R. PLATT, Butler University, Department of Chemistry, Indianapolis, IN, USA, M.J. SAMIDE, Butler University, Indianapolis, IN, USA, and J.A. PLATT, Indiana University, School of Dentistry, Indianapolis, USA Using Archimedean principles to determine volumetric dimensional change of polymers may be associated with error due to the loss of unpolymerized components. Objectives: The study was designed to allow for identification and quantitation of components lost from resin core materials that were evaluated for volumetric dimensional change. Methods: The leachates in a freshly polymerized sample of each material were extracted into methanol and identified by mass spectrometry. After initial identification, individual leachates were purified and analyzed by NMR. Response factors were determined for predominant leachates from one of the materials (CorePaste, Den-Mat). Distilled water from a 6-month evaluation of dimensional change for five core materials was supplied by Indiana University. A 1.000 ml aliquot of the aqueous sample was washed with two 10 ml portions of dichloromethane. The organic layer was isolated, dried, and concentrated by rotary evaporation. Benzophenone was added as a standard prior to evaporation. Gas chromatographic analysis (GC-FID) was performed to quantitate the compounds. Results: The most abundant leachates found in the methanol extraction were triethyleneglycol-dimethacrylate (TEGDMA) and methyl benzoate (MB). After dichloromethane extraction, any leachates were detected only in trace amounts. The detection limits for this study were 0.022 mg for TEGDMA and 0.061 mg for MB. Conclusions: The compounds TEGDMA and MB are detected when extracted with methanol and trace amounts may be present in the dichloromethane extractions. The ability to account for a mass loss of 0.01 mg would lead to significant verification of the precision of the Archimedean method used by Indiana University. Because this threshold level falls below the detection limits for this study (0.02 mg for TEGDMA and 0.06 mg for MB), it is not possible to determine whether error using Archimedean methodologies becomes significant due to leaching of unpolymerized components in the dental material. | ||
| Seq #344 - Prosthodontic Polymers 10:15 AM-11:30 AM, Saturday, 13 March 2004 Hawaii Convention Center Exhibit Hall 1-2 | ||
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Back to the Dental Materials: VI - Polymer Materials-Mechanical Properties and Degradation Program
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