Links between oral diseases and metabolic syndrome: a narrative review

Context Metabolic syndrome is a group of conditions that involves insulin resistance, hypertension and low high-density lipoproteins; all of which increases a patient's risk of developing cardiovascular diseases. With the prevalence of metabolic syndrome on the rise, researchers have explored the potential for its association with oral diseases, such as periodontitis, apical periodontitis, peri-implantitis, caries and oral potential malignant disorders.Objectives This narrative review explores and collates the current evidence regarding the complex pathophysiology of metabolic syndrome and its associations with oral diseases.Current knowledge and gaps in research It is widely known within the scientific community that oral and systemic diseases can be associated, often with a bidirectional link. Metabolic syndrome and a number of oral diseases are characterised as inflammatory conditions and hence the most well-studied plausible pathway lies within the pro-inflammatory response. Although some oral diseases have an established association, other conditions have not been explored in depth. While the direction of this research seems to be positive, there must be further qualitative longitudinal studies to determine causality. Most importantly, there must be an increased focus on population-wide education to relay the importance of oral health maintenance in association to systemic diseases.Conclusion This narrative review highlights the existing evidence about metabolic syndrome links with oral diseases, while outlining the gaps in the available evidence and direction of future research and population-wide education.