200 MHZ NUCLEAR MAGNETIC RESONANCE SPECTROMETER

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The long-term objectives to be fulfilled by the Nuclear Magnetic Resonance (NMR) Spectrometer acquisition by the American Dental Association Health Foundation Paffenbarger Research Center are divided into two groups: those objectives met by a broadband liquids probe, and those objectives met by a broadband solids CP/MAS probe. Liquids probe work will range from routine 1H and 13C assays of organic components of the PRC adhesive protocol for human patient clinical trials to detailed mechanistic studies on the organic components of experimental and commercial systems. Newer systems containing fluorine and phosphorous can be studied by 19F and 31p NMR as well. Radiation damage to DNA and proteins will be studied by 1H, 13C, 31P, 2H, 17O and 15N NMR spectroscopy on labelled compounds extracted from cellular tissues. Determination of the distribution of various orthophosphate ions in aqueous and nonaqueous solution as a function of pH will utilize 31P NMR capabilities. The 13C, 19F, 31P NMR study of the polymerized product of the PRC and commercial adhesive systems will comprise a major use of the broadband solids probe. The study of phosphorous in teeth will utilize the solids probe 31P capability. The solids probe, via 29Si observation, will characterize glass inserts for composite restorations of interproximal and occlusal surfaces. Novel initiation mechanisms for the polymerization of composite and adhesive systems will be observed via both solution and solid phases. Performance standards and levels of detection of structural differences in solids will be determined. The health relatedness of this NMR spectrometer acquisition lies primarily in the field of prevention and repair of tooth defects. By applying solutions of organic components and composite materials which bond to the surface of dentin and enamel the amount of "drilling" (and need for anesthetics) will be reduced because there will no longer be the necessity to cut away vital supportive dentin to make undercuts and mechanically lock the filling material into place. By improving adhesive bonding treatments, it will become possible to provide protective coatings of exposed root surfaces where there has been gingival recession due to age or disease.