Kidney failure and oral health - A systematic review and meta-analysis of observational studies

Background: The interplay between oral health and chronic kidney disease (CKD) is not fully understood, but both conditions may influence each other through chronic inflammatory states. This systematic review and meta-analysis aim to investigate the association between CKD and oral health. Methods: The review included observational studies (cross-sectional, case-control, and cohort) involving adults (≥18 years) comparing individuals with and without CKD regarding the number of missing teeth, edentulism, or the decayed, missing, and filled teeth (DMFT) index, a recognized indicator of oral health. The databases PubMed, Scopus, and Web of Science, together with references, were searched up to October 10, 2024. The results were synthesized using meta-analysis in RevMan software. Results: Eight case-control studies from Portugal, Turkey, Japan, Brazil, and Thailand were included, with sample sizes ranging from 30 to 204 participants. CKD patients had significantly more missing teeth (mean difference +3.17; 95% CI 2.07–4.28), fewer filled teeth (mean difference −1.23; 95% CI -1.82; −0.64), and higher DMFT scores (mean difference +2.60; 95% CI 1.34; 3.86) compared to controls. No significant difference was found in the number of decayed teeth (mean difference 0.31; 95% CI -0.15; 0.76). The methodological quality of studies ranged from 4 to 7 stars. Conclusions: Patients with CKD, especially those on hemodialysis, experience more tooth loss and higher DMFT scores, highlighting a gap in oral health care within dialysis units. Although the findings highlight the importance of addressing oral health in CKD patients, further studies are needed in developed countries to better understand the interplay between both conditions.