Study Of Effect Of CPPs To Affect Tooth Demineralization And Remineralization In Vitro

Enamel demineralization is one of complications in the process of orthodontic treatment,and incidence is highest.We should always concerned about the health of patients teeth,especially keeping good oral hygiene can effectively prevent the occurrence of demineralization complications,once "white spot" is seen on enamel surface we must do something actively.At the same time to urge patients to maintain oral health,symptomatic treatment should be adopted also.The use of calcifying solution in the process of orthodontic treatment is the effective method to enamel demineralization.In recent years,with the function of casein phosphopeptides -CPPs being further researched,CPPs-calcium complex promoting the enamel remineralization was confirmed,but the ratio inl which CPPs combines with calcium to promote the remineralization is still unclear.So this paper focused on usage ratio of CPPs and calcium and its role in inhibiting demineralization.Objective:To verify the effect of CPPs combining with the traditional compounding calcifying solution to promote enamel remineralization in vitro,and identified the ratio with the use of calcium and CPPs and the role in inhibiting demineralization.Methods:Experiment 1:Deionized water was a blank control.There were 0%,2.4%,4.8%,7.2%,9.6%,5 kinds of calcifying solution,in which the ratio of CPPs/Ca²⁺ was 0,0.4,0.8,1.2 and 1.6,as treat groups classified by the amount of CPPs.42 enamel pieces produced early to artificial enamel caries were divided 6 groups by microhardness after demineralization in simple randomization, so there were 7 pieces in each group.After seven days immersed in different calcifying solution, Knoop hardness of enamel surface was tested.And the amount of calcium depositing on artificial enamel caries was known by testing the calcium remained in the solution after immersing by atomic absorption spectrometry.Before and after treatment enamel surface morphology changes was observed by scanning electron microscope.At last,enamel pieces were immersed in 0.1mmol/L Rhodamine B then observed by confocal laser scanning microscope(CLSM),and the pore in enamel after remineralization was analyzed.Experiment 2:30 enamel pieces were randomly divided into five groups,each with six.5 groups were carried out in five different treatment(group A:deionized water+deionized water, and Group B:CPPs+deionized water,Group C:deionized water + lactic acid,Group D:CPPs+ lactic acid,Group E:fluor protector+lactic acid).The amount of calcium from enamel surface detected by atomic absorption spectrometry was compared among 5 groups.Results:Experiment 1:1.One enamel piece of every group was observed by SEM randomly.The pictures showed a large number of spherical mineral deposits block on the surface of decalcified enamel after remineralization.The mineralizer filled the fissures and pits appearing after demineralization of enamel and made osteoporosis surface become dense.But the surface of decalcified enamel had the same appearance after deionized water treating as before,expansion of the enamel rod sheath and surface defects still clearly visible.2.The result from residual calcifying solution analyzed by atomic absorption spectrometer shown there was not significant difference among calcifying solution contained CPPs(P＜0.05),but they were different from common calcifying solution significantly(P＜0.05).3.Except deionized water group,five kinds of calcifying solution increased the surface hardness of decalcified enamel,and the difference was significant(P＜0.05).Among different calcifying solution with CPPs,hardness change had no difference(P＞0.05),but was higher than that of ordinary,and there was a significant difference (P＜0.05).4.Enamel pieces disseminated with Rhodamine B were observed under confocal laser scanning microscope.The number of pore decreased significantly after treated by 5 different calcifying solution,but AF(average fluorescence) among different groups had no significant difference(P＞0.05).Experiment2:Experiment 2:There was no significant difference among A,B,and E groups in amount of calcium dissolution(P＞0.05).The difference between C and D was significant (P＞0.05).But the amount of calcium dissolution from A,B and E group was less than C and D respectively,and the difference was significant(P＜0.05).Conclusion:CPPs has great contribution to calcium deposition in the decalcified enamel surface, and promotes remineralization.Effect of CPPs combining with common calcifying solution is better than it alone.When CPPs/Ca²⁺ is 0.4,the ratio is compatible to promote the remineralization.On pH value constant,and not increasing the calcium,expanding the proportion of CPPs /Ca²⁺ over 0.4 has no contribution to remineralization,confocal laser scanning microscope makes for analysis of pore change because of demineralization and remineralization.After remineralization,the number of pore is decreasing.CPPs doesn't prevent demineralization directly,and will not enable the demineralization of enamel surface.Fluor protector film has effective resistance to the acid.