Diversity of the Oral Microbiome Between Dentate and Edentulous Individuals

Objective: Measurement of saliva microbes is promoted as a way to detect oral and systemic disease, yet it is also reported that a multitude of factors affect the oral microbiome. Differences in the saliva microbiome of subjects with and without dentition were assessed. Subjects and Methods: 50 dentate and 50 edentulous subjects provided saliva samples after removal of dentures in the later group. 16s rRNA gene sequencing, followed by QIIME- based data processing and statistical analysis, was done to detect changes in makeup of the salivary microbiome in the two groups. Results: Twenty-six taxa assigned to a genus were differentially abundant between the two groups. Bacteria diversity decreased in the edentulous group. Major differentially abundant genera were: Clostridia, Actinomyces, Shuttleworthia, and Veillonella. Remarkably, 25 of the differences in taxa were decreases that occur in the edentulous group. The only exception was the genus Streptococcus. Importantly, the decrease in specific genera in the edentulous group was detected reproducibly whether we analyzed all 100 samples at once or 50 at a time as independent datasets. Conclusion: There is greater diversity in the salivary microbiome of dentate individuals compared to edentulous individuals. Furthermore, measurement of 16s rRNA genes in the bacteria of the saliva can be used to reproducibly measure changes in the oral microbiome that occur with edentulism.