King's College 65-patient oral health study

King’s College London researchers said a two-year clinical study found that successful root canal treatment in 65 patients was associated with improved blood sugar control, healthier lipid profiles and lower inflammatory burden. The paper, published on November 18, 2025 in the Journal of Translational Medicine, tracked patients treated for apical periodontitis, a common root canal infection. King’s said the work was the first clinical study to follow blood chemistry changes after treatment for that infection. The study included co-authors from King’s and the University of Helsinki. ### Which dental condition did the researchers study? Apical periodontitis was the condition at the center of the study. The infection affects tissue around the tip of a tooth root and can follow pulp disease, allowing bacteria from an infected tooth to enter the bloodstream, according to King’s College London. King’s College London said the infection has been associated with higher cardiovascular risk and impaired glycaemic control. (pmc.ncbi.nlm.nih.gov) The paper’s authors wrote that there had been limited evidence on whether successful endodontic treatment was linked to broader metabolic improvement. ### What exactly did the team measure over two years? The study followed 65 patients from Guy’s and St Thomas’ NHS Foundation Trust for two years after root canal treatment. (pmc.ncbi.nlm.nih.gov) Researchers collected serum samples before treatment and again at 3 months, 6 months, 1 year and 2 years, then used nuclear magnetic resonance spectroscopy to measure 44 circulating metabolites linked to diabetes and cardiovascular risk. The Journal of Translational Medicine paper said the team also compared metabolomic findings with metabolic syndrome indicators, inflammatory biomarkers, and blood and intracanal microbiome data. The authors reported significant postoperative changes in 24 of the 44 metabolites they tracked. ### What changed after treatment? The paper reported a significant reduction in branched-chain amino acids at the 3-month review, a significant decrease in glucose and pyruvate at the 2-year review, and short-term reductions in cholesterol, choline and fatty acid levels. (pmc.ncbi.nlm.nih.gov) The authors also reported a progressive increase in tryptophan, which they described as part of the broader metabolic shift seen after treatment. King’s College London summarized the findings as improved glucose metabolism, better lipid profiles and reduced inflammation over time. In a university release, lead author Dr. Sadia Niazi said the findings showed root canal treatment “may also help reduce the risk of serious health conditions like diabetes and heart disease.” ### Did the study say root canals prevent diabetes or heart disease? (pmc.ncbi.nlm.nih.gov) The paper did not say root canal treatment prevents diabetes or heart disease. The authors said successful endodontic treatment was “associated with” improved glucose and lipid metabolic profiles and reduced systemic inflammation, and said the findings suggested a potential role in mitigating cardiometabolic disease risk. The study was a self-controlled longitudinal cohort, not a randomized trial. (kcl.ac.uk) That means it tracked changes in the same patients over time rather than testing treatment against a separate control group for disease outcomes such as heart attacks or new diabetes diagnoses. That is an inference from the study design described in the paper. ### Why were King’s and Helsinki both involved? The author list on the paper includes Yuchen Zhang, Adrien Le Guennec, Pirkko Pussinen, Gordon Proctor and Sadia Ambreen Niazi. (pmc.ncbi.nlm.nih.gov) Pussinen is the University of Helsinki-linked co-author cited in the study record, while Niazi is the King’s College London senior lecturer highlighted in the university’s release and faculty profile. King’s College London said the work supports closer coordination between dental and medical care. (pmc.ncbi.nlm.nih.gov) Niazi said in the university release that dentists and general practitioners should work together to monitor blood markers and support earlier diagnosis and treatment of root canal infections. ### Where can readers find the study itself? The Journal of Translational Medicine published the paper under the title “Successful endodontic treatment improves glucose and lipid metabolism: a longitudinal metabolomic study.” The DOI listed in the article record is 10.1186/s12967-025-07110-0, and the paper is available through PubMed Central. (pmc.ncbi.nlm.nih.gov) (kcl.ac.uk)