In Vitro Study Of Fluoride Nano Hydroxyapatite On Remineralization Of Early Root Caries

Objective:In this experiment,the fluoride nano hydroxyapatite,nano hydroxyapatite,fluoride foam and sodium fluoride solution as mineralizer and remineralization of early root surface caries,changes were observed after demineralization and remineralization of root surface morphology and microhardness,compare the effect of fluoride nano hydroxyapatite,nano hydroxyapatite,fluoride foam and sodium fluoride solution on remineralization of early root surface caries.Methods: One month after the removal of 42 premolar teeth,the tooth root surface was not complete and the caries were removed.Scanning electron microscopy was used to observe the surface morphology of the root surface after demineralization and the microhardness of the root surface after demineralization was measured by a digital microscope microhardness tester.The 40 models of root caries were randomly divided into 5 groups: blank control group,FnHA group,nHA group,fluoride foam group and sodium fluoride solution group.Each group was treated with the corresponding reagent,and the changes of root surface morphology and microhardness were observed by 7d pH cycle and 20 d remineralization.Statistical analysis was used to compare the single factor analysis of variance between different groups,such as the statistical significance of the difference between the two groups,then LSD-t was compared between the two groups,before and after the experiment using a single sample t test.Results:The use of fluoride nano hydroxyapatite were observed by scanning electron microscopy of root surface of honeycomb structure disappeared,there are a large number of crystal deposition and surface smoothing.The use of nano hydroxyapatite treated with scanning electron microscope showed root surface disappearance of honeycomb structure,there are large deposits of grain,but the surface smoothness is worse than the fluoride nano hydroxyapatite group.Use of fluoride foam and sodium fluoride solution treatment group root surface visible scaly and small grain deposition.In the blank control group,there was still a certain amount of pit structure.The fluoride nano hydroxyapatite group,nano hydroxyapatite group,fluoride foam group and sodium fluoride group root surface microhardness values were higher than the root surface microhardness after demineralization,the difference was statistically significant(P < 0.05).The fluoride nano hydroxyapatite group,nano hydroxyapatite group,fluoride foam group and sodium fluoride solution group root surface microhardness values were higher than the control group,the root surface microhardness and fluoride nano hydroxyapatite group was significantly higher than that of nano hydroxyapatite group,fluoride foam group and sodium fluoride solution group,the differences were statistically significant(P < 0.05).Conclusion: The effect of nano hydroxyapatite on early root surface caries was better than that of nano hydroxyapatite,fluoride foam and sodium fluoride solution.