Apical Periodontitis: A Hidden Non-Communicable Disease in Global Health - a Narrative Review of Longitudinal Research.

Apical periodontitis (AP) is a highly prevalent oral disease increasingly recognized as a hidden non-communicable disease (NCD) with systemic consequences. This narrative review integrates the findings from longitudinal studies on a well-characterized AP cohort to elucidate the link between AP systemic conditions. Evidence highlights AP as a reservoir for low-grade bacteremia and systemic inflammatory burden. Elevated baseline levels of inflammatory markers including fibroblast growth factor-23, interleukin-1β, high-sensitivity C-reactive protein, and asymmetric dimethylarginine were observed in AP patients, correlating with lesion size and microbial profiles in both root canal and blood microbiomes. AP is also associated with altered metabolic syndrome indicators - such as hemoglobin A1C, triglycerides, low-density lipoprotein and shifts in serum metabolomic profiles involving glucose, lipid, branched-chain amino acid, and tryptophan metabolism. Importantly, successful endodontic treatment can lead to significant reductions in inflammatory biomarkers, improved metabolic syndrome (MetS) indicators, and improved glucose and lipid metabolism. Collectively, these findings position AP as an important NCD which impacts beyond the oral cavity via linking to systemic conditions and related cardiometabolic risks, highlighting the importance of its timely diagnosis and successful management.