Analysis Of Differences And Influencing Factors In Fungal Composition In Saliva And Gingival Plaque Of Childhood Caries

Background:The incidence of dental caries in children is high.If it is not prevented in time,it will endanger the physical and mental health of children.The study of oral cariogenic microbiota mainly focuses on bacterial community,and the effect of fungal community on childhood caries still needs further exploration.High-throughput sequencing technology is widely used in the field of oral microbial research,but how to optimize the experimental process to improve the detection rate of low-load oral fungal flora is worth exploring.The most commonly used samples for the study of oral microorganisms are oral saliva and supragingival plaque.However,there are still few studies on the composition and differences of fungal communities in oral saliva and supragingival plaque of childhood dental caries.And it is worth exploring whether children’s gender and dentition period have an impact on the composition of fungal communities in oral saliva and supragingival plaque.Objective:1.Optimize the high-throughput sequencing process to improve the detection rate of oral fungi.2.To evaluate the difference of fungal community composition of unstimulated saliva and supragingival plaque in childhood caries.3.To analyze the effects of gender and dentition on the fungal composition of unstimulated saliva and supragingival plaque in childhood caries.Methods:A total of 63 children aged 2-9 years with dental caries were recruited,including 36 males and 27 females,24 deciduous dentition and 39 mixed dentition.Unstimulated saliva and supragingival plaque samples were collected from each child and grouped according to gender and dentition stage.High throughput sequencing was performed on the internal transcribed spacer 2 of the sample fungal genes,and biological information analysis and statistical analysis were performed.Results:In this study,by optimizing the PCR amplification process,16 samples with initial amplification of class C concentration were increased to 6 class A and 10 class B,which effectively improved the concentration of PCR samples.A total of 7 phyla,10 genera and 10 species of fungal groups were detected by sequencing.The dominant phylum of unstimulated saliva subgroup and supragingival plaque subgroup were Basidiomycota and Ascomycota.At the genus level,the top three genera in the two subgroups were Cryptococcus,Wickerhamomyces and Candida.The top three species at the species level were Cryptococcus_longus,Wickerhamomyces_anomalus and Candida_albicans.The species difference analysis showed that there were significant differences in the relative abundance of Cryptococcus,Wickerhamomyces,Cryptococcus_longus,and Wickerhamomyces_anomalus in unstimulated saliva and supragingival plaque subgroups(p<0.05),as well as significant differences in a and βdiversity between the two subgroups(p<0.05).There was no significant difference in fungal community composition and diversity between male and female subgroups in unstimulated saliva,between male and female subgroups in supragingival plaque,and between deciduous dentition and mixed dentition in supragingival plaque(p>0.05).But there were significant differences in Ascomycota and Basidiomycota between deciduous dentition and mixed dentition subgroups in unstimulated saliva(p<0.05),as well as significant differences in a andβ diversity between the two subgroups(p<0.05).Conclusion:1.Optimizing the PCR amplification process can effectively increase the detection concentration of PCR samples,thereby increasing the detection rate of fungal communities.2.There were significant differences in the composition and diversity of fungal communities between unstimulated saliva and supragingival plaque in childhood dental caries.3.Gender had no effect on the fungal composition of unstimulated saliva and supragingival plaque in childhood dental caries,but the dentition period would affect the composition of fungal communities in unstimulated saliva.