Systemic Health Associations of Apical Periodontitis: A Systematic Review of Observational Studies

Apical periodontitis (AP) is a chronic inflammatory condition of the periapical tissues, often caused by pulp necrosis. While primarily localized in the oral cavity, evidence suggests that AP may contribute to systemic inflammation, influencing conditions such as cardiovascular disease, diabetes, pregnancy complications, osteoporosis, and autoimmune disorders. This review examines the association between AP and various systemic health conditions. A systematic search of PubMed, Scopus, and EMBASE was conducted, focusing on observational studies reporting systemic outcomes in individuals with AP. Data extraction and risk of bias assessment were conducted with evidence quality evaluated using the GRADE framework and a narrative synthesis by disease category. Of the 37 identified studies, 13 were included in the final analysis. Findings showed moderate-certainty evidence linking AP to increased cardiovascular risk, poorer glycemic control in diabetics, adverse pregnancy outcomes (e.g., preeclampsia, low birth weight), higher AP prevalence in osteoporotic patients, and greater persistence of AP in autoimmune disease cohorts. AP was associated with a two to threefold increase in cardiovascular disease and preeclampsia risk, as well as delayed healing in diabetics. AP may contribute to systemic diseases through shared inflammatory pathways, exacerbating conditions such as cardiovascular disease, diabetes, and pregnancy complications. This review emphasizes the importance of including AP in systemic health assessments and suggests that interdisciplinary management is vital for patients with comorbid conditions. Longitudinal studies are necessary to further explore the causal links between AP and these systemic conditions.