الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This investigation aimed to assess the impact of different remineralizing approaches (reparative or regenerative) on the SMH, mineral content and surface morphology of bleached tooth enamel.
In this investigation, 57 crowns from extracted human maxillary central incisor were utilised. They were bleached using 40% hydrogen peroxide chemically activated bleaching gel, and randomly divided into three main groups (n=19) based on the remineralizing agent will be applied after the bleaching. group I was Curodont Repair {SAP (P11-4)}, group II was GC Tooth Mousse (CPP-ACP) and group III was Whitesmile Mousse (sodium fluoride). All specimens were kept in artificial saliva at 37°C throughout the experiment duration following whitening and remineralization processes. The specimen’s surface microhardness, elemental assessment and surface morphology evaluation were carried out at 4-time intervals; before bleaching, immediately after bleaching, 24 hours and 1 week after remineralization using Vickers microhardness tester and Energy Dispersive X-ray analysis combined to a scanning electron microscope. The results were recorded, tabulated, and statistically analysed.
Overall SMH results among the three study groups showed a statistically significant rise in Vickers Hardness Number (VHN) only 24 hours after remineralization (RM). While no statistically significant difference was present in VNH at baseline, after bleaching and 1 week after RM. The highest VHN was recorded for Gp I, followed by Gp II, followed by Gp III 24 hours after RM, with the statistical significance only between Gp I and Gp III.
Overall Mineral content was also improved after RM in all groups. All specimens showed significant increase in (Ca)2+, (PO4)3- and CaP ratio levels 24 hours and 1 week after RM compared to after bleaching levels in all groups. With a statistical significance between Gp I
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with Gp II and between Gp II with Gp III, while Gp I and Gp II showed statistical insignificance.
Regarding the surface morphology improvement, all the used agents improved the surface of the bleached enamel 24 hours and 1 week following their application. 24 hours after RM, SAP (P 11-4) showed noticeable decrease in surface irregularities with accentuated superficial deposition of granules. CPP-ACP showed a moderate decrease in the irregularities with moderate superficial deposition of granules. And sodium fluoride presented the least surface improvement with minimal superficial deposition of granular structures.
One week after RM, SAP (P11-4) presented further improvement in the enamel’s surface morphology after bleaching with both superficial and deep granular depositions in the enamel surface. CPP-ACP treated specimens also showed a further surface morphology improvement after bleaching with an increased superficial granular deposition only, but still to a lesser degree to those produced by SAP (P11-4). Sodium fluoride presented the least surface improvement with only superficial granular deposition only without any depositions in deeper areas on the enamel surface.
It was concluded that SAP (P11-4) is highly beneficial in initial SMH recovery compared to CPP-ACP and Fluoride. Both SAP (P11-4) and CPP-ACP had an approximate remineralizing effect on the bleached enamel in relation to each other, and a higher effect in relation to fluoride. The surface morphology of bleached enamel is best improved by SAP (P11-4).