Analysis Of Oral Microbiomes In Chronic Pericoronitis Between Adults And Children Using Full-length 16s RRNA Gene Amplicon Sequencing

Objective:To investigate the changes in the composition and metabolites of oral microbiomes in gingival crevicular fluid and saliva during chronic periodontitis in adults and children,and to explore the correlations between oral microbiomes and chronic periodontitis.Methods:1.A total of 40 patients(19 females,21 males)were recruited at the Department of Stomatology,Fifth Hospital of Shanxi Medical University between July 2021 and October2022.Among them,there are 20 patients with chronic pericoronitis and 20 patients with non chronic pericoronitis.Extract the gingival crevicular fluid and saliva from the oral cavity of the study subjects,and store them at-80 ℃ for testing after liquid nitrogen treatment.2.Extract microbiomes DNA from gingival crevicular fluid and saliva samples.Using the Pac Bio Sequel II sequencing system from Shanghai Lingen Biotechnology Co.,Ltd.for16 S full-length amplicon sequencing,and using professional analysis software for bioinformatics analysis.3.All statistical analyses were conducted using the R statistical software package.Differences with P < 0.05 were considered statistically significant.4.This study was approved by the institutional ethics committee of the Fifth Affiliated Hospital of Shanxi Medical University,and all patients or guardians participating in the study have signed informed consent forms.Results:1.Microbiomes alpha diversity analysis: The alpha diversity of chronic pericoronitis group in adult saliva is higher than the non chronic pericoronitis group.There was a statistically significant difference in Chao1 index(Observed index P=0.029;Chao1 index P=0.019);Chronic pericoronitis group in children is lower than its non chronic pericoronitis control,and the difference in Shannon index was statistically significant(Observed index P=0.023;Shannon index P=0.019).2.Microbiomes beta Diversity analysis: Of microbiomes in adult saliva,there are differences of beta diversity between non chronic pericoronitis and chronic pericoronitis groups(P=0.048).There may be slight differences between the adult and child pericoronitis groups(P=0.062).3.Analysis of microbiomes species composition shows that there is difference in Porphyromonas gingivalis in gingival crevicular fluid of adult non chronic pericoronitis patients compared to adult chronic pericoronitis patients;Compared to adult patients with chronic periodontitis,the expression of Fusobacterium animalis in gingival crevicular fluid is higher,while pediatric patients with chronic periodontitis exhibit differences in Porphyromonas gingivalis expression;Compared to children with chronic periodontitis,there is a difference in Paraburkholderia kururiensis in gingival crevicular fluid of children with non chronic periodontitis.Compared to the significant expression of Neisseria subflava in the saliva of adult patients with non chronic pericoronitis,there is a difference in the expression of Lactobacillus iners in the saliva of children with non chronic pericoronitis;Compared to adult non chronic pericoronitis patients,the expression of Neisseria subflava is significant,and there is a difference in the expression of Lactobacillus iners in the saliva of adult chronic pericoronitis patients;Compared to children with chronic periodontitis,adult patients with chronic periodontitis have differences in the levels of Lactobacillus iners and Bifidobacterium pseudocatenulatum in their saliva;Compared to children with chronic pericoronitis,there is a difference in Bifidobacterium pseudocatenulatum in saliva of children with non chronic pericoronitis.4.Metabolomics analysis: Through non targeted metabolomics analysis,in POS and NEG modes it was found that various levels of differential metabolites can be screened,including organic acids,nucleotides,amino acids and their derivatives,indoles,and many other products.Conclusion:1.Compared to non chronic pericoronitis patients,there is difference in the oral microbiomes of chronic pericoronitis patients;The species composition at the species level varies significantly compared to the bacterial community classification at the genus level and above.2.There are numerous oral microbiomes metabolites in the saliva of patients with chronic pericoronitis,and there are differences in metabolic products at different levels.