A Study On Preventing Deciduous Teeth By Fluoride Iontophoresis

Objective:To evaluate the fluoridation of deciduous enamel after fluoride iontophoresis in vitro;To observe the changes of deciduous teeth caries and the prevention effect of the fluoride ioninfiltration;To researchthe prevention effect of the fluoride ion infiltration with different decay degrees of the deciduous teeth,providing reference for the selection of the appropriate timing of the intervention.Methods:Part1:54 deciduous incisors sample were used and randomly divided into nine groups.Seven experimental groupswere treated with fluoride iontophoresis under several conditions,other two control groups were soaked in 2%NaF solution and deionized water,respectively.After that,each sample was placed into 5ml 0.1 mol/L lactic acid solution,Fluoride concentrations were measured with fluoride ion-specific electrode 48h later,then statsiticanlyasis were performed.Part2:The children aged 3-4 year-old from 12 preschools in Zhangjiagang were selected with cluster random sampling method.They were selected for clinical examination annually and received a bi-annual fluoride ion infiltration application.Caries incidence?mean dmft?the increase dmft were calculated.Also they were divided into three groups according to the dmft calculated by the first oral examination:caries-free group(dmft=0)?low caries group(1?dmft<4)?caries high caries group(dmft>4,and the increase dmft was compared in two years later.Results:Part1:The mean values of fluoride concentration in fluoride iontophoresis group,NaF group and the deionized water group was(0.0940± 0.0200)?(0.0554 ± 0.0147)and(0.0388 ± 0.0012)mg/L,respectively.The concentration of fluoride in the fluoride iontophoresis group was significantly higherthan that in the NaF group(P<0.05).In concentration-dependent test,the mean values of fluoride concentration in 1%,2%,3%fluoride iontophoresis group was(0.0925 ± 0.0123)?(0.0940 ± 0.0200)and(0.1025 ±0.0023)mg/L,respectively,The concentration of fluoride in the 3%fluoride iontophoresis group was significantly higher than that in 1%and 2%fluoride iontophoresis group(P<0.05).In current strength-dependent test,the mean values of fluoride concentration in the 0.3 mA?0.4 mA?0.5 mA fluoride iontophoresis group was(0.0928 ± 0.0098)?(0.0940 ± 0.0200)and(0.1045 ± 0.0033)mg/L,respectively.The concentration of fluoride in 0.5 mA fluoride iontophoresis group was significantly higher than that in 0.3 mA and 0.4 mA fluoride iontophoresis group(P<0.05).In time-dependent test,the mean values of fluoride concentration in the 2min?3min?4min fluoride iontophoresis group was(0.0933 ± 0.0014)?(0.0940 ±0.0200)and(0.0952 ± 0.0016)mg/L,respectively.The concentration of fluoride in three groups had no significant difference(P>0.05).Part2:It was found that from 2013 to 2015,the prevalence of dental caries was 50.83%?61.99%and 68.00%,respectively;The mean number of decayed,missed and filled teeth(dmft)was 2.06 ± 3.03?3.06 ± 3.80 and 3.47 ± 3.9,respectively.The prevalence of dental caries and mean dmft increased gradually as the children grew up.There was significant difference among 3 years(x2 =113.567,P<0.05;F =69.730,P<0.05).The increase dmft in 2014.2015 was 1.01 ± 1.53 and 0.53 ± 0.97,respectively.The increase dmft in 2015 was decreased and the difference between 2014 and 2015 was significantly(t=10.933,P<0.05).At the same time the increase dmft in two years later among carie-free group?low caries group?high caries group was 0.82 ± 1.39?2.U ± 2.15?2.41 ± 2.10,respectively(F=135.58,P<0.05),the difference between the three groups and every two groups was significantly(P<0.05).Conclusion:1.Fluoride iontophoresis is an effective way to increase the concentration of fluoride in deciduous enamel.This study showed that improve the concentration of fluoride and increase the current strength could enhance the concentration of fluoride in enamel effectively.2.Using the application of fluoride ion can prevent the occurrence of dental caries.The high caries activity may weaken the prevention effect of the fluoride ioninfiltration,The optimal timing of intervention is before the caries appeared.