Kenner G H, Haskell E H, Hayes R B, Baig A, Higuchi W I
Division of Radiobiology, University of Utah, Salt Lake City, Utah 84103, USA.
Calcif Tissue Int. 1998 May;62(5):443-6. doi: 10.1007/s002239900457.
Electron paramagnetic resonance spectroscopy (EPR) was used to study synthetic hydroxyapatite and approximately 1, 2, and 6% synthetic carbonated apatites, deorganified dentine, and enamel. The carbonated apatites were synthesized by hydrolysis of dicalcium phosphate. Comparisons were made with spectra from enamel and deorganified dentine. Microwave power saturation and dose responses were determined for the synthetic materials. The Marquardt version of the Levenberg decomposition method was used to extract individual signals from the apatite data. Two samples of dentine were irradiated with 25 and 100 Gy, respectively, from a 60Co source. The first sample was then deorganified at 200 degreesC using the Soxhlet extraction technique. A third sample was irradiated with 100 Gy after deorganification. The resulting EPR spectra were then compared. It was determined that the dosimetric signal of 2% synthetic carbonated apatite was approximately the same as that of enamel. It was also verified that the dosimetric signal saturates at about 2% in synthetic carbonated apatites. The study established that the precenters responsible for the dosimetric signal (g perpendicular = 2.0018, g parallel = 1.9985) are preferentially concentrated in the surface-accessible region of the mineral component, as shown by the approximately 80% attenuation of the dosimetric signal in dentine following deorganification. The precenters responsible are not destroyed by the deorganification since the magnitude of the dosimetric signal from the dentine specimen irradiated following deorganification was approximately twice that of the comparable untreated, irradiated sample. Finally, the dose response of 2 and 6% synthetic carbonated apatites was determined.
电子顺磁共振波谱法（EPR）被用于研究合成羟基磷灰石、约1%、2%和6%的合成碳酸磷灰石、脱有机化牙本质和牙釉质。碳酸磷灰石通过磷酸二钙水解合成。将所得光谱与牙釉质和脱有机化牙本质的光谱进行比较。测定了合成材料的微波功率饱和度和剂量响应。使用Levenberg分解方法的Marquardt版本从磷灰石数据中提取单个信号。分别用来自60Co源的25 Gy和100 Gy对两个牙本质样品进行辐照。然后使用索氏提取技术在200℃下对第一个样品进行脱有机化处理。第三个样品在脱有机化后用100 Gy进行辐照。然后比较所得的EPR光谱。确定2%合成碳酸磷灰石的剂量测定信号与牙釉质的大致相同。还证实合成碳酸磷灰石中的剂量测定信号在约2%时达到饱和。该研究确定，负责剂量测定信号的前中心（g垂直 = 2.0018，g平行 = 1.9985）优先集中在矿物成分的表面可及区域，如脱有机化后牙本质中剂量测定信号约80%的衰减所示。负责的前中心不会因脱有机化而被破坏，因为脱有机化后辐照的牙本质样品的剂量测定信号强度约为未处理的可比辐照样品的两倍。最后，测定了2%和6%合成碳酸磷灰石的剂量响应。
