Impacts Of Probiotic Yogurt On Oral Microorganism Among Five-year-old Children With Severe Early Childhood Caries

Objective:The aim of this study was to observe the impacts of probiotic yogurt on oral microorganism among five-year-old children with severe early childhood caries.Methods:Twenty five 5-year-old children who met the inclusion and exclusion criteria with dmfs ? 6 were recruited for this study.The participants were randomly divided in two groups using randomized double-blind contolled method.The participants in experimental group drank probiotic yogurt for 2-weeks while others in control group drank yogurt without probiotic for 2-weeks.The non-irritating saliva and surgingival plaque were collected before,after yogurt drinking and 1-month post-drinking:(1)Colony-counting method was used to count S.mutans in salivary at baseline,after 2 weeks' yogurt drinking and 1 month post-drinking period.Salivary pH was recorded at the same time point.Repeated-measures ANOVA was used to analyze data.(2)16srDNA high through-put sequencing was used to observe the diversity of the oral microbial community composition in plaque biofilm at baseline and after yogurt drinking.Alpha-diversity,Beta-diversity and OUT based on the sequence similarity was analysed.Results:There were 13 participants in experimental group and 12 participants in control group.(1)Impacts of probiotic yogurt on count of S.mutans in salivary and salivary pH:? Compared to the baseline,the number of S.mutans in both groups decreased significantly(P<0.05)after yogurt drinking.However,there was no significant difference between the two groups.After 1-month post-dinking,the number of S.mutans increased back to the level of the baseline in two groups and there was no significant difference between two groups(P>0.05).? Compare to the baseline,there was no change of salivary pH in both group after yogurt drinking and there was no significant difference between two groups(P>0.05).(2)Impacts of probiotic yogurt on microbial community composition and diversity of plaque biofilm:There were some discrepancies between two groups before and after yogurt drinking.At the phylum level,Fusobacteria decreased significantly after yogurt drinking both in two groups(P<0.05).At the genus level,the number of Campylobacter,Leptotrichia,Tannerell,and Porphyromonas increased after intervention significantly(P<0.05).There was no significant difference in Simpson Index between two groups after yogurt drinking(P>0.05).Conclusion:There was no significant difference in S.mutans counts and salivary pH between the experimental group and the control group after 2-week's yogurt drinking.There was no evidence to show drinking probiotic yogurt could prevent dental caries.To evaluate the impacts of probiotic yogurt on prevention and treatment of dental caries especially for 5-year-old children,a long-term application of probiotic yogurt should be explored.