Kubota K, Kameda A, Endo T
Department of Orthodontics, Nippon Dental University School of Dentistry at Niigata.
Shigaku. 1990 Aug;78(2):233-50.
With the purpose of studying the influence of enamel acid etching technique, and the effectiveness of a strengthening of tooth enamel by silicahydro gel method, the following groups were compared, analyzed and observed by the measurements of diffracted X-ray from thin layer specimens and by microarea X-ray diffraction from an X-ray crystallographic point of view. Group I: non-treated tooth enamel Group II: acid-etched tooth enamel Group III: tooth enamel by application of silicahydro gel method after being acid etched. The results obtained were as follows: 1. Qualitative analyses by the measurements of diffracted X-ray from thin layer specimens 1) Ca5(PO4)3F, Ca5F (PO4)3 and Ca3(PO4)2.xH2O were detected in every group, and Ca3(PO4)2.xH2O demonstrated a high reliable value in group III. 2) In comparison with groups I and II, group III clearly revealed a peak shift toward high angle side, however, a halo peak was not recognized in every group. 3) As a result of evaluating crystallinity, crystallinity became favorable in order of group II, group I and group III. 4) A-axis lattice constant shortened in order of group II greater than group I greater than group III, and c-axis lattice constant shortened in order of group II greater than group I = group III. 2. Qualitative analyses by microarea X-ray diffraction 1) Solid solution of Ca5(PO4)3F and Ca5(PO4)3(OH) proved to exist in every group and in each microarea. 2) A halo peak appeared in group II and showed the trend of disappearance in group III, however, no peak shift was observed in all groups. From the foregoing results, the loss of the utmost enamel surface layer exhibiting high crystallinity and the lowering of crystallinity by acid etching technique were revealed from an X-ray crystallographic point of view and furthermore if silicahydro gel method was applied, it was suggested that enamel would be restored or that crystallinity would be enhanced.
为了研究牙釉质酸蚀技术的影响以及硅胶水凝胶法强化牙釉质的效果，从X射线晶体学角度，通过对薄层标本的X射线衍射测量以及微区X射线衍射，对以下几组进行了比较、分析和观察。第一组：未处理的牙釉质；第二组：酸蚀后的牙釉质；第三组：酸蚀后采用硅胶水凝胶法处理的牙釉质。得到的结果如下：1. 通过薄层标本的X射线衍射测量进行定性分析：1）在每组中均检测到Ca5(PO4)3F、Ca5F(PO4)3和Ca3(PO4)2·xH2O，且Ca3(PO4)2·xH2O在第三组中显示出较高的可靠性值。2）与第一组和第二组相比，第三组明显显示出向高角度侧的峰位移，然而，每组均未识别出晕峰。3）作为评估结晶度的结果，结晶度按第二组、第一组和第三组的顺序变好。4）a轴晶格常数按第二组大于第一组大于第三组的顺序缩短，c轴晶格常数按第二组大于第一组 = 第三组的顺序缩短。2. 通过微区X射线衍射进行定性分析：1）证明在每组和每个微区中均存在Ca5(PO4)3F和Ca5(PO4)3(OH)的固溶体。2）第二组出现晕峰，且在第三组中有消失的趋势，然而，所有组均未观察到峰位移。从上述结果可以看出，从X射线晶体学角度揭示了表现出高结晶度的最外层牙釉质的损失以及酸蚀技术导致的结晶度降低，此外，如果应用硅胶水凝胶法，则表明牙釉质将得到恢复或结晶度将得到提高。
