The role of oral hygiene in inflammatory bowel disease.

The 'hygiene hypothesis' suggests that a reduction in the microbial exposure due to improved health measures has contributed to an immunological imbalance in the intestine and increased the incidence of autoimmune diseases such as inflammatory bowel diseases (IBD). Accordingly, we investigated associations between oral hygiene practices and IBD. We developed and administered a multiple choice questionnaire to evaluate oral hygiene and dental care practices of 137 subjects (83 with IBD and 54 healthy controls). Of the 83 IBD cases, 31% had ulcerative colitis and 69% had Crohn's disease. For subjects with IBD, the frequency of brushing at disease onset was significantly higher than in controls (P=0.005). Also, the frequency of use of dental floss and breath freshener at disease onset was significantly higher in IBD patients (P=0.005 and<0.001, respectively). Also, patients with IBD more frequently visited their dentist at disease onset (P<0.001) and continued to visit their dentist more often (P<0.001). IBD cases had a higher frequency of dental complications such as tooth caries (P=0.007), oral ulcers (P=0.04) and dry mouth (P=0.001). These findings suggest that oral hygiene practices may cause alterations in the flora of the oral mucosa, which causes imbalance in the gut microbiome (dysbiosis), and thereby contributes to the pathogenesis of IBD. Conversely, the increased frequency of dental problems in IBD patients might be due, at least in part, to alterations in oral flora or to their disease.