Oral health and the microbiome dysbiosis in inflammatory bowel disease

Abstract

Inflammatory bowel disease (IBD), encompassing Crohn’s Disease and Ulcerative Colitis, is a chronic inflammatory condition of the gastrointestinal tract closely linked to microbiota imbalances. While the role of gut microbiota in IBD has been extensively explored, the contribution of the oral microbiome remains less understood. Dysbiosis of the oral microbiota in IBD patients has been associated with an increased prevalence of oral diseases such as caries and periodontitis. Moreover, therapeutic interventions for IBD can alter microbial composition, with some bacteria emerging as potential predictors of treatment response. This study aims to systematically review the literature on microbiome dysbiosis in IBD and its impact on patients’ oral health. A comprehensive systematic search was performed using the electronic databases PubMed, Scopus, and Cochrane to identify studies with relevant data. This review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, addressing a research question structured using the Population, Intervention, Comparison, and Outcomes (PICO) framework. Four hundred and sixty-nine articles potentially relevant were identified and after applying PRISMA guidelines and inclusion/exclusion criteria, twelve articles were included in this review. The results suggest a consistent dysbiosis of the oral and gut microbiome in IBD, marked by reduced diversity and enrichment of pro-inflammatory bacteria, particularly Prevotella, Veillonella, and Fusobacterium. It also emphasized the close relationship between oral health and IBD, with common oral manifestations such as periodontitis, reinforcing the relevance of the oral microbiome as both a mirror and potential driver of systemic inflammation. These insights highlight the need for integrated dental and gastrointestinal care. Further research is needed to confirm microbial markers, understand causal mechanisms, and assess how interventions may restore microbial balance and improve clinical outcomes.

Date of Award	11 Jul 2025
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Ana Peixoto Gomes (Supervisor) & Nélio Jorge Veiga (Co-Supervisor)