Selenium in periodontal health and disease: A narrative review.

Periodontal disease (PD) has a high prevalence worldwide, with periodontitis regarded as the leading cause of tooth loss in the adult population. Several conditions have been identified as contributing to its development. The role of different micronutrient imbalances in oral inflammation has recently become an important research topic. Selenium and selenoproteins, through their redox function, play a significant role in controlling immune-inflammatory mechanisms associated with various systemic diseases. However, there is a paucity of studies on the relationship between selenium and/or selenoproteins and periodontal disease. This narrative review aims to analyse how selenium may be involved in the development of PD and to update recent advances regarding the influence of selenium supplementation on periodontal health. It specifically focuses on four key points: 1) the role of selenium in the oral cavity, 2) the analysis of clinical evidence of glutathione peroxidase and selenium as diagnostic markers for PD, 3) the evaluation of selenium supplementation for alleviating the effects of PD, and 4) selenium nanoparticles as a future perspective. Selenium plays an important role in periodontal health due to its antioxidant, anti-inflammatory, antimicrobial and regenerative properties. Glutathione peroxidase is a key selenoprotein in PD. Salivary selenium may serve as a potential diagnostic biomarker, while selenium supplementation, particularly in nanoparticle form, could be a promising adjunctive strategy for periodontal therapy. However, more studies are needed to confirm its clinical efficacy and safety.