Eastman Dental Institute


Unravelling the mouth-gut axis and its association with IBD

Professor Andrew SmithDr Sean Nair, Professor Francesco D’Aiuto, Dr Maja Sabalic

There are number of studies conducted across the globe that have reported a higher prevalence of oral inflammatory disease in patients with inflammatory bowel disease (IBD). Patients with IBD are 4-6 times more likely to co-present with periodontitis (gum disease) than the general population. Until very recently there had been very little information on the potential mechanistic link between these two chronic inflammatory diseases. 

In July 2020 a paper was published that demonstrated that in an animal model, bacteria from the mouth, translocated to and colonized the lower digestive tract resulting in gut inflammation.

We do not know if the same thing happens in humans and how this may influence oral and gut inflammatory disease.

This study will therefore address the following questions:

  1. What links inflammation in the mouth and intestine?
  2. Do the microbes within the mouth have a role to play in intestinal inflammation?
  3. Are there biomarkers which could be used to identify individuals at risk of developing oral and intestinal inflammatory disease?


We plan to study patients who have both oral and bowel inflammation in order to understand what drives the development of disease in two locations. 

Samples will be taken from the gut and mouth of patients who suffer from both or either condition, and the bacterial communities characterised using 16S rRNA sequencing. We will attempt to identify species that are associated with disease activity and determine how these bacteria influence the immune system.

We will try and identify a biomarker or immune profile, which would enable the identification of patients who are at a higher risk of developing both oral and intestinal disease.

Potential impact

Oral manifestations in patients with inflammatory bowel disease are scarcely detected by general practitioners and gastroenterologists, even though the evidence for a higher prevalence of oral disease in this specific patient group is becoming more apparent. 

We hope that our study will highlight the need for gastroenterologists and dentists to be more aware of the potential association between the two conditions. 

We would also like to develop a screening protocol to identify patients who are susceptible to developing both oral and intestinal manifestations and provide some form of preventative treatment.