Assessment of The Remineralization Potential of Recently Developed Nano Hydroxyapatite on The Demineralized Enamel Around orthodontic Brackets

Objective: This study was evaluated the ability of Nano hydroxyapatite (nano-HAP) to remineralize the demineralized enamel layer around the orthodontic brackets. Materials and Methods: This study was done on thirty sound freshly extracted permenant premolars. 3M-Unitek brackets were bonded to the buccal surfaces of all specimens. The specimens were artificially demineralized and randomly classified into 3 equal groups A, B and C. They were immersed in artificial saliva for 10days and during this period, group B was treated with 20% nano-HAP varnish, group C was treated with 3%nano-HAP +0.145%sodium fluoride(NaF) paste, while group A was the control group. Selected specimens of each group were scanned by scanning electron microscope (SEM) and assessed by energy dispersive x-ray analysis(EDAX) before and after remineralization, then all samples were subjected to enamel color changes assessment by spectrophotometer and surface roughness assessment by profilometer. The results were statistically analyzed. Significance of the results was set at 0.05. Results: Showed that there were significant increase (P<0.001) in both Calcium and Phosphorus levels after remineralization by nano-HAP. This was detected by EDAX and confirmed by SEM. There was a significant improvement in the color measurements after application of nano-HAP in the study groups when compared to the control group (P<0.001), also the surface roughness has significantly decreased (P<0.001). Conclusion: The findings of our study indicated that nano-HAP with the used protocol in this study could be effective in repairing the demineralized enamel around the orthodontic brackets, restoringthe enamel surface smoothness and its color.