A Systematic Review and Meta-Analysis of Animal Models on the Possible Link Between Periodontitis and Inflammatory Bowel Diseases.

Background
Rapidly evolving evidence, from preclinical and clinical studies, indicates a possible connection between inflammatory bowel disease and periodontitis. This study aimed to summarize the evidence from preclinical in vivo studies regarding the possible link between periodontitis and colitis.Methods
A systematic literature search was performed and resulting studies were screened against predefined eligibility criteria; data from included studies were extracted, and meta-analyses were performed whenever possible.Results
Thirty-four publications using mice or rats were included; 26 experiments evaluated the effect of inoculation with oral bacteria on experimental colitis, 3 the effect of experimental periodontitis on experimental colitis, and 7 the effect of experimental colitis on periodontal status; 45% (9), 78% (14), 57% (12), and 89% (16) of the studies found a significantly higher body weight loss, shorter colon length, higher disease activity index (DAI), and higher intestinal histopathological assessment scores (IHA), respectively, in animals exposed to inoculation with oral bacteria and experimental colitis compared with animals with only colitis. Meta-analyses confirmed that inoculation with oral bacteria significantly aggravated colitis, that is, significant negative overall effect on body weight, colon length, DAI, and IHA. Among the tested bacteria, Fusobacterium nucleatum had the strongest effect followed by Porphyromonas gingivalis. The results of the remaining interactions and comparisons are inconclusive due to a limited number of studies and differences in study design.Conclusions
Inoculation with the periodontitis-associated bacteria F. nucleatum and probably also P. gingivalis exacerbates experimental colitis in mice. It is yet unclear whether colitis can affect periodontal health and/or disease.Currently available preclinical in vivo studies confirm that inoculation with periodontitis-associated bacteria exacerbates experimental colitis. It remains, however, unclear whether colitis affects periodontal health or disease.