Different Measures For Caries Prevention In Preschool Children And Its Effect On Streptococcus Species

Objective; Duraphat and anti-Streptococcus mutans immunoglobulin of yolk (IgY) were evaluated in caries prevention on preschool children of Lin’an City and International caries accessment and evaluation system Ⅱ(ICDAS-Ⅱ) were used for caries diagnose to evaluated enamal lesion. By compared with education, fluoride and immunization against dental caries of deciduous teeth caries of preschool children preventive effect, and quantitative analysis six Streptococcus species before and after the intervention in saliva of caires-frree children.Method:2.5to4.5year old children were collected by cluster random sampling method and divided into three groups, control group (n=138), only oral health education for parents or caregivers, fluoride group (n=110), Duraphat (5%sodium fluoride) were applied on deciduous teeth by professional doctor every six months, immune group (n=119), anti Streptococcus mutans IgY spray were used every in kindergarten.Oral examinations were based on ICDAS-II and questionnaires were collected for the oral health behaviors of children. After the first visit, oral examinations were carried out every6months, followed for24months.Saliva of caries free children in three groups(30children in control group,25children in fluoride group and26children in immune group)were collected before the first visit, one months later, every6months after until the end of follow-up.DNA extraction from saliva and bacterial gene specific primers were designed for quantitative analysis six Streptococcus species by real time PCR including Streptococcus mutans, Streptococcus sobrinus, oral Streptococcus, Streptococcus gordonii, Streptococcus salivarius, Streptococcus sanguis and total Streptococci.Results:At first visit, the caries free children distribution were same in three groups(control:37%, fluoride:28%and immune group31%,P>0.05). Gneralized Linear Mixed Model analysis showed the fluoride group had better effect on caries free children than control (t=-1.317, P=0.027) whereas in all children the immune group had better effect (t=2.585, P=0.022).The saliva bacteria quantification showed that S. salivarius at6months and S.sanguinis at18and24months were significantly different (P<0.05) between the control and fluoride group.S.sanguinis decreased significantly within1month in immune group and18months and24months later total Streptococci, S.oralis, S.sanguinis, S.salvarius, S.gordonii and S.mutans were significant different (P<0.05) from the control groupConclusion:Fluoride and anti-caries immunization spray have reduced the caries in preschool children. The absolute quantitative real-time PCR method was established in this study for analysis six oral Streptococcus species, which may be useful in the future epidemiological researches on dental caries and oral micro ecology. The long-term application of anti-S.mutans IgY spray in24months had effect on streptococcus species numbers in immune group.