A novel Parvimonas OTU is inversely associated with having caries or fillings in children

BackgroundDental caries is the most common chronic oral disease in children, but its etiology is complex and multifactorial. The association of the oral microbiota with caries is underexplored in children. We investigated saliva microbiota in Finnish children and aimed to identify microbial biomarkers associated with the risk of having caries or fillings (CF). MethodsWe examined 400 Finnish children (180 girls, 220 boys) aged 7-9 years who provided stimulated saliva samples and underwent clinical oral examinations at baseline of the Physical Activity and Nutrition in Children study. Of these children, 261 (65%) were with CF and 139 (35%) were without CF. We characterized the saliva microbiota using the 16S rRNA gene sequencing, examined differences in the abundance and composition at the phylum and genus level between these two groups, and studied the associations of selected Operational Taxonomic Units (OTUs) with the risk of having CF in crude and adjusted (OTUs, age, Silness-Loe plaque index) models. ResultsAlpha diversity and richness did not differ between the groups (p>0.1 for Shannon, inverse Simpson, and Chao1 indices) in the total sample nor when analyzed among girls and boys separately. Beta diversity differed between the groups in the total sample, and when girls and boys were analyzed separately (p corrected by false discovery rate method [pcorr] [~] 0.001). In total, 80 OTUs differed between the groups at the genus level (pcorr<0.01). Two OTUs were independently associated with the risk of having CF. A novel Parvimonas OTU was inversely associated with having CF (odds ratio [ORcrude] 0.49, 95% confidence interval [CI] 0.32 to 0.75). In addition, an OTU of probably Streptococcus mutans was positively associated with having CF (ORcrude 6.01, 95% CI 3.49 to 10.36). ConclusionA Parvimonas species represented by a novel OTU is independently and inversely associated with the risk of having CF in children.