Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Operative Dentistry

Elemental and ultramorphological analysis were done for all specimens in all groups and subgroups for sound unbleached enamel, after bleaching procedure (under manufacturer instructions) and after pH cycle. Quantitative energy dispersive x-ray spectroscopy elemental analysis was performed on the enamel surface to determine the elemental levels (%) of calcium (Ca), phosphorus (P). The calcium (Ca) and phosphorus (P) contents were evaluated in weight percent (wt. %) and the mean Ca/P ratios were calculated. The ultra-morphological analysis was done using the Environmental Scanning Electron Microscope. One image was obtained from the center of each enamel surface specimen with magnification of 4000X. Data were collected, tabulated and statistically analyzed. Results: Quantitative energy dispersive x-ray spectroscopy elemental analysis showed a statistical significant difference among the three groups (control, bleaching without fluoride and bleaching with fluoride) in Ca wt % and P wt % while it showed no significant difference among three groups after performing pH cycle. However Ca/P ration showed no significant difference among the three groups but showed a significant difference after performing pH cycle

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