Assessing the Applicability of Saliva for Gene Expression Studies in Advanced Periodontitis

Periodontitis is a common chronic inflammatory disease that affects the supporting structures of the teeth and can lead to tooth loss if left untreated. Beyond its local impact, the condition is increasingly recognized as a component of systemic inflammation, involving activation of immune pathways and cytokine networks. Understanding these molecular processes requires reliable biological material that reflects both local and systemic immune activity. So far, most gene expression studies in periodontitis have been performed using peripheral blood, which provides information about systemic immune status but is obtained through an invasive procedure. In this study, we aimed to evaluate whether saliva could serve as a convenient and non-invasive alternative for RNA-based functional analyses of immune system-related genes in patients with advanced periodontitis. Saliva samples were collected from twelve patients diagnosed with severe disease. Total RNA was extracted, and its concentration and purity were measured spectrophotometrically. Despite natural variability among individuals, all samples yielded RNA suitable for further gene expression evaluation. Our findings suggest that saliva can provide RNA of adequate yield and purity to analyze the expression of immune-related genes in periodontitis. Given its easy and non-invasive collection, saliva represents a promising biological source for molecular investigations of inflammatory processes and may support broader diagnostic and research applications in health sciences.