Effects of multiple tongue conditions on the diversity and composition of the oral microbiota

Objective The present study examined the effects of multiple tongue conditions on the diversity and composition of the oral microbiota to obtain a more detailed understanding of their potential role in health and disease.Method Ninety-three subjects were classified according to tongue conditions, such as a yellow tongue coating, the presence or absence of swelling of the sublingual vein, a red tongue or red tongue tip, a fissured tongue, enlarged tongue, geographic tongue, and tooth marks. The oral microbiota was examined using α- and β-diversity metrics and taxonomic composition analyses.Results α-Diversity was significantly lower in subjects with a fissured tongue than in those without. A β-diversity analysis revealed distinct microbial community structures between these subjects. Taxonomic profiling showed a higher abundance of Firmicutes and sulfur-metabolizing bacteria in subjects with a fissured tongue. However, these differences were not retained after age adjustment. Age-restricted sensitivity analyses identified age-independent microbial signatures associated with a fissured tongue, including a reduced abundance of Veillonella and Granulicatella in saliva samples.Conclusion Morphological abnormalities of the tongue are associated with distinct oral microbiome profiles. These features may reflect oral microbial dysbiosis and could be relevant for future studies exploring non-invasive markers of oral health.