Experimental Study On The Effect Of Enamel After Fluoride-removing Material And Mineralization Fluid With Beyond Cold Light Whitening

Objective:By observing and analyzing the physical properties and morphological structureof enamel after applying cold light bleaching, fluoride-removing agent and saliva. Tostudy the influence of fluoride-removing agent and saliva on micro hardness,composition and structure of healthy teeth enamel surface, in order to provide thetheory basis for clinical application.Method:Chose thirty healthy maxillary premolars extracted from the orthodontictreatment, and sliced the teeth into four equal parts longitudinally along buccolingualand mesiodistal. Selected100enamel samples in the120samples, randomly dividedinto four groups: blank control group, Beyond bleaching group (instant group、1weekgroup、2weeks group), Beyond bleaching with I liquid group (instant group、1weekgroup、2weeks group), Beyond bleaching with I&II liquid group(instant group、1week group、2weeks group)，each group contained10teeth samples.1week groupand2weeks group were persevered in saliva in thermostatic water bath box of37℃for one week and two. The enamel surface micro hardness of all samples weremeasured by micro hardness tester, and the calcium, phosphorus content and the ratioof calcium/phosphorus on enamel surface were tested by the energy spectrumanalysis meter. At the same time, used scanning electron microscopy on teethsamples.The data was statistically analyzed by SPSS19.0software.Result:1, Scanning electron microscope observation, blank control group shows normalenamel surface morphology and smooth surface.Instantly groups: Beyond bleaching group has acid etched enamel surface change, surface roughness, and porosity increased, and there are obviousdemineralization dissolve on enamel center and its surrounding, nest structure can beseen. Beyond bleaching with I liquid enamel surface acid etches obviously, surfaceroughness is serious than Beyond bleaching group, normal enamel surface structurehas disappeared, replaced by a clear gap and surface depressions, enamel centercolumn is not obvious. Beyond bleaching with I&II liquid enamel roughness is betterthan Beyond bleaching group, void ratio increased, the pores and voids showsmicro-melting enamel surface.One week groups: minerals is deposited on Beyond bleaching group, Beyondbleaching with I liquid group, Beyond bleaching with I&II liquid group enamelsurface, remineralization can be seen in and around the enamel center column, surfacevoid ratio reduced, voids structure intensity decreased. In high magnification, Beyondbleaching with I liquid group has more multi-pore structure than Beyond bleachinggroup, and that is low in Beyond bleaching with I&II liquid group.Two week groups: Beyond bleaching group, Beyond bleaching with I liquidgroup, Beyond bleaching with I&II liquid group were relatively flat enamel surface,mineral deposits recovered enamel obviously, recovered to normal enamel form.Beyond bleaching with I liquid group can still see part of the enamel surface porestructure, but significantly less than the number of Beyond bleaching with I liquidgroup. Beyond bleaching group and Beyond bleaching with I&II liquid group canfind little pore structure.2, Micro hardness test, in instantly groups: comparison of microscopic hardnessvalue of Beyond、Beyond+I groups and blank control group, p<0.05,difference isstatistically significant. there were no significant differences among the remaininggroups.Beyond、Beyond+I液显微硬度比值较空白对照组有显着性差异，p<0.05；Beyond、Beyond+I&II液显微硬度比值较Beyond+I组有显着性差异，p<0.05，具有统计学意义3, Energy spectrum analysis, in instantly groups: comparison of microscopichardness value of Beyond、 Beyond+I groups and blank control group,p<0.05,difference is statistically significant; comparison of microscopic hardness value of Beyond、Beyond+I&II groups and Beyond+I group, p<0.05,difference isstatistically significant; there were no significant differences among the remaininggroups.Conclusion:1, Only use bleaching agent will increase enamel erosion and enamel surfaceroughness, showing a significant demineralization change.2, Bleaching combined remineralization solution, the enamel surface physicalproperties is constant, and no significant changes happen on micro hardness. Afterbleaching in clinical treatment, re-mineralization teeth can accelerate the depositionof calcium and phosphorus on enamel surface after bleaching.3, The saliva has the function of remineralization, saliva can increase the mineralcontent of enamel surface of demineralization which is caused by whitening.