A growing body of research has identified strong associations between metabolic syndrome and several oral diseases, including periodontitis, apical periodontitis, dental caries, peri-implantitis, and oral potentially malignant disorders.
These findings suggested that inflammation may serve as a common link and that oral and metabolic health may influence each other more directly than previously understood.
Metabolic syndrome is defined as a cluster of conditions—insulin resistance, central obesity, hypertension, low high-density lipoprotein (HDL )cholesterol, and elevated fasting glucose—that together increase the risk of cardiovascular disease and type 2 diabetes.
A widely accepted definition requires at least three of the following criteria: waist circumference over 40 inches in men, blood pressure above 130/85 mmHg, triglycerides over 150 mg/dL, low HDL cholesterol, and fasting glucose exceeding 100 mg/dL.
Patients with metabolic syndrome (MetS) have been found to be at significantly higher risk for periodontitis, a chronic inflammatory disease that affects gum and supporting tissues. Studies have shown they are twice as likely to develop periodontitis compared to those without MetS. Elevated levels of inflammatory markers such as C-reactive protein and interleukin-6 have been observed in both conditions.
Apical periodontitis—characterized by inflammation at the rootof a tooth due to infection—has also been linked with MetS. Individuals with this condition exhibited higher levels of metabolic risk markers. Following root canal treatment or apical surgery, patients not only showed improved oral health but also reductions in systemic inflammatory markers, suggesting a connection between endodontic therapy and improved metabolic profiles.
MetS has also been associated with higher prevalence of dental caries. In a study involving nearly 14,000 Chinese adults, caries were more common among participants with MetS, especially those with hyperglycemia. While other MetS components such as hypertension and elevated blood sugar showed no significant relation to caries risk.
Oral potentially malignant disorders ., which includes conditions that can precede oral cancer, has shown increased incidence in individuals with MetS. Studies point to metabolic abnormalities such as obesity, insulin resistance, and high glucose. These risks may be amplified in populations with high rates of betel nut use, smoking, or alcohol consumption.
Peri-implantitis, a condition marked by bone loss around dental implants due to inflammation, also appears more common among individuals with MetS. One study reported a 36.9% prevalence of peri-implantitis in MetS patients, compared to 26.3% in those without the syndrome. Hyperglycemia in particular was identified as a possible risk factor, likely due to its effects on immune response and decreased blood supply.
Despite mounting evidence of associations between MetS and oral diseases, most findings are based on cross-sectional data. Researchers stress the need for longitudinal studies to establish causality and further clarify the direction of these relationships. Improved understanding could support more integrated care strategies, recognizing oral health as a component in managing systemic conditions like MetS.
The authors reported no conflicts of interest.
Source: BDJ