Characterizing Caries and Periodontitis Experience Using Microbiome and GWAS

Objectives: The goal of the study was to find associations between common genetic variations and dental findings, considering the microbiome characterized in saliva.
Methods: Saliva samples were taken from 866 patients for genome-wide genotyping for single nucleotide polymorphisms (SNPs) and 16S rRNA gene sequencing for microbiota composition identification. Principal components analysis (PCA) was performed on dental codes to identify principal components (PCs) using both individual and tooth level clinical definitions. Regression analyses were used to test PCs identified as a response (y) to individual SNPs, microbiota, and demographics as predictors (x). Full versus reduced model comparison estimated the explanatory utility of the SNP and/or microbiota data.
Results: The oral biomes and the genetic make-up of individuals in each group were evaluated for similarities. The secondary caries component group showed genes that were related to angiogenesis, immune functions, and structural proteins, combined with age and Capnocytophaga, Neisseria, and Rothia. The primary caries component showed genes that were related to oncogenic pathways with cell growth and regulation and angiogenic genes combined with age, sex, prevotellaceae, streptococcus, and treponema as common factors. The advanced caries phenotype included genes responsible for cell growth and regulation, ion channels, and immune functions, combined with age and Gemella, Aggregatibacter, and Leptotrichia. Patients with endodontic treatment and periodontitis showed associations that included genes for structural proteins, transcription regulation, and protein metabolism, and Fusobacterium, Atopobium, Campylobacter, Pasteurellaceae as factors influencing the phenotype. One group with periodontitis showed associations with genes regulating cell growth, transcription and immune function, age and Fusobacterium, Treponema, Prevotella, and Selenomona as factors of the phenotype. A second group with periodontitis included genes for cell growth and regulation, transcription, hemodynamic function, and immune function, age as common factors towards the phenotype.
Conclusions:
Dental caries and periodontitis are the result of complex and specific interactions between individual susceptibility and microbial colonization.