Connecting Oral Health to Systemic Disease – Road Ahead for Interdisciplinary Research and Care

Dentistry as a discipline was traditionally viewed as a subject limited to the oral cavity; however, the paradigm shifts with mounting evidence suggesting that oral health is definitely linked to systemic health.1 This change necessitates that researchers, clinicians, and policymakers rethink their perspective and establish oral health as a cornerstone of systemic well-being. Dental caries and periodontitis are among the most prevalent oral diseases worldwide. According to the Global Burden of Disease Study 2019, untreated dental caries in permanent teeth was the most common health condition globally among noncommunicable diseases, affecting approximately 2.5 billion people, while severe periodontitis affected nearly 796 million people.2 While both diseases are biofilm mediated, the etiopathogenesis varies. However, despite the differences, they share a common potential for systemic influence. These oral health challenges, has a direct impact on oral function, quality of life as well as associated with systemic diseases.3 Consequences of disruption of oral microbial equilibrium, termed dysbiosis, extend beyond oral health. The oral microbiome is now linked not only to the oral diseases but also to the initiation or progression of numerous systemic diseases, such as cardiovascular diseases, metabolic disorders like type 2 diabetes, neurological diseases, autoimmune diseases, and even some malignancies.4,5 There is now a lot of epidemiological, mechanistic, and clinical research that backs up the idea of an “oral-systemic link.”5,6 The ulcerated epithelium of periodontal disease can affect the distant organs by providing an entry point for oral microbes and their inflammatory byproducts to the systemic circulation. Potential causal relationship between periodontitis and cardioembolic stroke, depression, diabetes, as well as nonalcoholic fatty liver disease is established.5 Similarly, animal studies have shown that Streptococcus mutans (a primary bacterium in dental caries) can accelerate atherosclerotic plaque growth and promote macrophage invasion following arterial injury.7 Evidence suggests an association between dental caries and primary hypertension in children and adolescents, with caries potentially serving as a contributory factor when other causes are ruled out.8 These can be bidirectional, such as the U-shaped relationship between body mass index and dental caries, which signifies that those who are underweight or obese exhibit a significantly higher burden of untreated dental caries.9 Despite these mounting data, the evidence for the oral–systemic link is limited and insufficient. Scoping reviews on dental caries indicate limited clinical evidence to demonstrate a substantial association between caries experience and the majority of cardiovascular illnesses in adults.4 Whereas observational studies frequently associate periodontitis with Alzheimer’s disease, rheumatoid arthritis, and other malignancies, several Mendelian randomization experiments have not succeeded in confirming a conclusive causal relationship.5 It is biologically feasible that dental caries may contribute to systemic health problems due to the oral microbiota spreading into systemic circulation through the root canal space or the marginal periodontium. However, determining causality still requires further validation of whether it is biologically feasible and clinically relevant through experimental studies such as animal models, in vitro molecular mechanisms, and interventional clinical trials. It is crucial to strengthen the evidence showing cause and effect, evaluate biomarkers, and explore treatment methods that consider both oral and overall health results.3 Collaboration between dentistry, medicine, and public health is vital. Oral health should be integrated into primary healthcare systems. Improving awareness to public, enhancing insurance coverage, and providing preventive therapies may address these inequities and improve systemic health outcomes. Oral health disparities mainly impact low- and middle-income nations, where access to preventive treatment is restricted.3 Oral health should be prioritized to reduce the worldwide burden of chronic diseases and enhance quality of life. The future of oral health research depends on interdisciplinary collaboration and on integrating genetics, microbiome studies, and digital health technologies to understand and address the connections between oral health and overall health. Researchers should understand that oral health and systemic disease constitute an overarching research theme that integrates various areas of investigation, including molecular mechanisms, microbiome studies, epidemiology, clinical trials, and public health interventions. This integrative perspective highlights that oral health cannot be examined in isolation; rather, it must be recognized as a predictor of systemic well-being. The future lies in embracing this perspective, and researchers and clinicians can collaborate on efforts across disciplines to produce more meaningful data that are both clinically pertinent and globally significant, which influences healthcare outcomes. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.