الفهرس | Only 14 pages are availabe for public view |
Abstract Summary The objective of this study was to evaluate in vitro the effect of a constant cumulative dose of 60 Gy (20 Gy/day over three days) of gamma irradiation on the microhardness of enamel and dentin before and after demineralization and remineralization. The data in this study involved the measurement of MHV vickers microhardness on both radiated and nonirradiated gamma irradiation at a constant cumulative dose of 60 Gy (20 Gy/day). The study indicated the following points: (1) The results showed that the mean microhardness values of the nonirradiated enamel samples were decreased from 093932 kgf/mm2 to 55.722 kgf/mm2 after gamma irradiation, i.e. the decrease in the microhardness is 5.15%. (2) Also the mean microhardness values of the non-irradiated enamel samples were significantly decreased after demineralization, (3) The mean microhardness values of the demineralized non-irradiated enamel samples were significantly increased after remineralization, (4) Also the mean microhardness values of gamma- irradiated enamel were significantly decreased after demineralization, i.e. the decrease was significant. (5) The mean microhardness values of demineralized gamma-irradiated enamel were significantly increased after remineralization, (6) Meanwhile the mean microhardness values of the non-irradiated dentin samples were significantly decreased (7) Also, the results showed that the mean microhardness values of the non-irradiated dentin samples were significantly decreased after demineralization, i.e. the decrease in the mean microhardness was nonsignificant. Summary and Conclusions ____________________________________________________________________ 15 (8) The results showed that the mean microhardness values of the demineralized non-irradiated dentin samples were non-significantly increased (9) The results showed that the mean microhardness values of the gamma-irradiated dentin samples were non-significant. (10) The results showed that the mean microhardness values of the demineralized gamma irradiated dentin samples were non-significant. |