The Bidirectional Effects of Periodontal Disease and Oral Dysbiosis on Gut Inflammation in Inflammatory Bowel Disease

Abstract Background and Aims Inflammatory bowel disease (IBD) flares can lead to excessive morbidity and mortality. This study aimed to determine whether oral dysbiosis/periodontal disease (PD) is common in IBD and is associated with disease activity in IBD. Methods This single-center, prospective, cross-sectional, proof-of-concept, and observational study assessed the frequency of periodontal inflammatory disease and interrogated oral and stool microbiota using 16S rRNA gene amplicon sequencing of active-IBD (aIBD), inactive-IBD (iIBD), and healthy controls (HC). Questionnaires assessed diet, alcohol usage, oral hygiene behavior, and disease activity. A subset of participants underwent comprehensive dental examinations to evaluate PD. Results Periodontal disease was severer in aIBD subjects than in HC, as aIBD had poorer quality diets (lower Mediterranean diet scores) than iIBD and HC. Significant differences in microbial community structure were observed in unstimulated saliva, stimulated saliva, gingiva, and stool samples, primarily between aIBD and HC. Saliva from aIBD had higher relative abundances of putative oral pathobionts from the genera Streptococcus, Granulicatella, Rothia, and Actinomyces relative to HC, despite similar oral hygiene behaviors between groups. Conclusions Our study suggests that patients with aIBD have severer periodontal disorders and higher relative abundances of putative ‘pro-inflammatory’ microbiota in their oral cavity, despite normal oral hygiene behaviors. Our data are consistent with the potential presence of an oral-gut inflammatory axis that could trigger IBD flare-ups in at-risk patients. Routine dental health assessments in all IBD patients should be encouraged as part of the health maintenance of IBD and as a potential strategy to decrease the risk of IBD flares.