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Τετάρτη 14 Μαρτίου 2018

44Ca doped remineralization study on dentin by isotope microscopy

Publication date: April 2018
Source:Dental Materials, Volume 34, Issue 4
Author(s): N. Hiraishi, S. Kobayashi, H. Yurimoto, J. Tagami
ObjectiveThe dental caries is developed as a result of an alternative course of mineral gain and loss. In order to distinguish between intrinsic Ca (tooth-derived mineral) and extrinsic Ca (solution-derived mineral) uptakes, a 44Ca doped pH-cycling was performed using 44Ca (a stable calcium isotope) remineralization solution.MethodsThe natural abundance of 40Ca and 44Ca is 96.9% and 2.1%, respectively. The remineralization solution was prepared using 44Ca to contain 1.5mmol/L CaCl2 (44Ca), 0.9mmol/L KH2PO4, 130mmol/L KCl, 20mmol/L HEPES at pH 7.0. The pH-cycling was conducted on bovine root dentin daily by demineralization (pH 5.0) for 2h, incubation in 0% (control) and 0.2% NaF (900ppm fluoride) for 2h and 44Ca doped remineralization for 20h. After 14days pH-cycling, the specimens were sectioned longitudinally. On the sectioned surface, isotope imaging of 40Ca and 44Ca labeled mineral distribution was observed by a high mass-resolution stigmatic secondary ion 77 (Camera IMS 1270, Gennevilliers Cedex, France).ResultsUptake of 44Ca was greater in intensity for the 0.2% fluoride group than the control, especially in the superficial lesions. The control group showed 40Ca (intrinsic) distribution in the subsurface lesions and in the superficial lesions, meanwhile the fluoride group showed 40Ca distribution limited in subsurface lesions. The total Ca (44Ca+40Ca) image revealed more homogeneously for the control than the fluoride group.SignificanceSince the fluoride-treated surface is more acid-resistant than intrinsic dentin, alternative minerals were dissolved from the intact intrinsic lesion in the demineralization cycle.

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from #ORL-AlexandrosSfakianakis via ola Kala on Inoreader http://ift.tt/2pcO9Ce

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