Effect Of Probiotic Toothpaste On Oral Microorganism Among Children Aged 5-year With Severe Early Childhood Caries

[Objective] Prevalence of dental caries is increasing in younger generation. As a new ecological preventive measure of dental caries, bacteriotherapy has been widely focused on. The aim of this study was to observe the effect of probiotic toothpaste on oral microorganism among children aged 5-year with severe early childhood caries, so as to evaluate the effect of probiotic toothpaste on prevention and treatment of dental caries, and to explore an effective and convenient measure for caries-prevention for children with severe early childhood caries.[Methods] 22 children who met the inclusion and exclusion criteria (aged-5,dmfs?6) were recruited in the study. By randomized double-blind controlled method,the subjects were randomly assigned to two groups: control group-brushing teeth with control toothpaste for 4 weeks, and experimental group- brushing teeth with probiotic toothpaste for 4 weeks respectively. (1) Colony-counting method was used to count S.mutans in salivary at baseline, after intervention and 1 month post-treatment period.Salivary pH was recorded at the same time point. Repeated-measures ANOVA was used to analyze datas. (2) 16srDNA high-throughput sequencing was used to observe the diversity of the oral microbial community composition in plaque biofilm at baseline and after intervention. Alpha-diversity, Beta-diversity and OTU based on the sequence similarity were analyzed.[Results] (1) Effect of probiotic toothpaste on count of S.mutans in salivary and salivary pH:? Compared to the baseline,count of S.mutans in both groups decreased significantly (p<0.05) after the intervention, but there was no statistical difference between two groups. But at one month after treatment there was a significant greater reduction in these counts in the intervention group compared to that after the intervention (p<0.05), and there was no statistical difference in the control group(p>0.05). ?Salivary pH increased significantly (p<0.05) of all the subjects after the intervention, regardless of the intervention group, and there was a significantly greater increase in salivary pH in the intervention group compared to the control group(p<0.05), but at one month after treatment in both the groups the salivary pH have no statistical difference compared to baseline(p>0.05). (2) Effect of probiotic toothpaste on microbial community composition and diversity of plaque biofilm:There were some discrepancies between the experimental group and control group,At the phylum level, the amounts of Proteobacteria, Bacteroidetes and Firmicutes in the experimental group were significantly decreased than in control group after the intervention(p<0.05). At the genus level, the amounts of Lactobacillus in the intervention group were significantly decreased than in control group after intervention (p<0.05). The mounts of Streptococcus decreased in both groups, but there was no statistical difference between two groups(p?0.05). In both groups,Simpson index had no statistical difference after the intervention (p>0.05).[Conclusion] 4-week application of probiotic toothpaste could inhibit the growth of S.mutans in saliva, and this effect could continue to 1- month after intervention. And it also could increase salivary pH significantly, but this effect is temporary. To evaluate the effect of probiotic toothpaste on prevention and treatment of dental caries,a long-term application of probiotic toothpaste should be explored.