Author/Editor		Schreiner, LJ; Cameron, IG; Funduk, N; Miljković, L; Pintar, MM; Kydon, DN
Title		Proton NMR spin grouping and exchange in dentin
Type		članek
Source		Biophys J
Vol. and No.		Letnik 59, št. 3
Publication year		1991
Volume		str. 629-39
Language		eng
Abstract		The nuclear magnetic resonance spin-grouping technique has been applied to dentin from human donors of different ages. The apparent T2, T1, and T1 rho have been determined for natural dentin, for dentin which has been dried in vacuum, and for dried dentin which has been rehydrated in an atmosphere with 75 percent relative humidity. All apparent spin relaxation has been analyzed for exchange between the spin groups in which the dentin protons exist; the analyses incorporate the results of selective inversion recovery T1 measurements which better probe the effects of exchange. The exchange analyses of the high fields and rotating frame spin-lattice relaxation have also been correlated to determine uniquely the inherent relaxation parameters of the proton spin groups constituting the dentin magnetization. The natural dentin contains protons on water, protein, and hydroxy apatite; these spins contribute 50 percent, 45 percent, and 5 percent to the total dentin proton magnetization, respectively. The water exists in three distinct environments, the dynamics of each environment has been modeled. In the natural dentin 30 percent of the water undergoes uni-axial reorientation. 52 percent of the water has similar relaxation characteristics to bound water hydrating a large molecule, and the majority of the remaining water acts as bulk water undergoing isotropic reorientation. The results are independent of the age of the donor.
Descriptors		DENTIN ADULT AGING BIOPHYSICS MIDDLE AGE MODELS, CHEMICAL NUCLEAR MAGNETIC RESONANCE WATER