الفهرس | Only 14 pages are availabe for public view |
Abstract Enamel white spot lesions are the earliest microscopic signs of demineralization under intact enamel, which may or may not lead to the development of caries (cavitation). The reason for the white spots is that the pathogenic bacteria have leached out a certain amount of calcium and phosphate ions from the enamel layer by the organic acids produced by these bacteria. Therefore, the increase in calcium or fluoride concentrations in the oral fluids was found to enhance lesion remineralization. Although fluoride therapy has been the cornerstone of cariesprevention and remineralization strategies since the introduction of water fluoridation schemes over 5 decades, but it has many limitations and drawbacks. Therefore the introduction of natural products has been used as promising sources for novel therapeutic agents. The majority of studies of natural products in the field of oral health have focused on their antimicrobial activities. Very few reported on the effects of natural products on the inhibition of dental erosion or decalcification processes of dental hard tissues.Gum arabic is considered to have an ability to enhance tooth remineralization, because of its high concentration of calcium. Aim of the study: The aim of this study was to investigate the remineralizing effect of gum arabic and the effect of sodium fluoride on artificial enamel white spot lesions qualitatively and quantitatively. Materials and Methods: Twenty-one caries-free human premolars were collected. Since teeth may differ in many properties as the enamel thickness, there was standardization through the use of the same tooth to be investigated before and after treatment. Samples were randomly divided into 3 groups, 7 premolars each, according to the treatment solution used as follows: group I: treated with 10 milligram per milliliter gum arabic solution. group II: treated with sodium fluoride at 1000 parts per million. group III: treated with distilled water.All samples under all groups were first evaluated regarding their enamel surface topography, surface Ca content and surface microhardness to act as a baseline, and during this the samples were named as Subgroups A (IA, IIA and IIIA). Then, all samples under all subgroups were subjected to artificial enamel white spots formation by immersion in a specific demineralizing solution, and after lesions creation they were evaluated again and named as Subgroups B (IB, IIB and IIIB). Samples were subsequently subjected to the three different treatment solutions previously mentioned and were named as Subgroups C as follows: Subgroup IC: Treated with GA. Subgroup IIC: Treated with NaF. Subgroup IIIC: Treated with DW. Teeth under different groups have received their treatment solutions in the form of pH cycles for 20 days, to simulate the fluctuation of demineralization and remineralization in the oral cavity.Samples evaluation was done using: Environmental Scanning Electron Microscope, Energy Dispersive X-ray Micro-analyzer, and Vicker’s micro-hardness tester. Results: I-Results of enamel surface topography: The environmental scanning electron microscopic examination of the middle part of the buccal surface of premolars before demineralization (subgroups IA, IIA & IIIA), revealed intact aprismatic surface layer with obvious perikymata ridges and few number of enamel rod ends at the perikymata grooves. After demineralization (subgroups IB, IIB & IIIB), enamel has shown etching patterns of either type I or irregular erosions in the form of craters, cracks (both narrow & wide were found) and cavitations. The examination after treatment revealed similar signs of enamel remineralization in gum arabic and sodium fluoride subgroups (IC and IIC respectively) in the form of regeneration of surface uniformity, prism cores appearing largely filled in with a consequent decrease of their diameter, globular precipitatesaccumulating inside prism cores and the characteristic keyhole pattern of the enamel rods was well defined without any signs of prism cores dissolution, compared to the subgroup of distilled water (IIIC) which showed no significant improvement in the enamel surface topography after treatment. II-Results of Enamel surface mineral content: There was a highly statistically significant decrease in enamel surface calcium weight percent values after demineralization (subgroups IB, IIB & IIIB). A highly statistically significant increase in calcium values was similarly noticed in subgroups IC and IIC after treatment with gum arabic and sodium fluoride solutions respectively, compared to the demineralized enamel of the corresponding groups but not reaching the original values of control enamel, while subgroup IIIC (treated with distilled water) showed no significant difference in the calcium values after treatment.III-Results of enamel surface micro-hardness: There was a highly statistically significant decrease in enamel micro-hardness in all groups after demineralization (groups IB, IIB & IIIB). A highly statistically significant increase in enamel microhardness values was similarly noticed in subgroups IC and IIC after treatment with gum arabic and sodium fluoride solutions respectively, compared to the demineralized enamel of the corresponding groups but not reaching the original values of control enamel, while subgroup IIIC (treated with distilled water) showed no significant difference in enamel micro-hardness after treatment. |