Oral fluid matrix metalloproteinase (MMP)-8 as a diagnostic tool in chronic periodontitis

Periodontal diseases that affect the marginal and apical periodontium result from the interaction between bacterial biofilm and the host response. Oral fluid biomarkers might aid clinical diagnosis. Matrix metalloproteinases (MMPs) are a family of 24 proteases that act in physiological and pathological conditions. They can degrade almost all extracellular matrix constituents and regulate inflammatory processes. They are mainly inhibited by tissue inhibitors
of metalloproteinases. The aim of this study was to perform a current literature review with a special reference on the diagnostic and clinical utility of oral fluid MMPs, especially MMP-8, and their inhibitors in periodontal and oral diseases. MMP-8 is the main collagenolytic MMP detected in oral fluids, such as saliva, oral mouthrinse, gingival crevicular fluid, and peri-implant fluid. MMP-8, and potentially MMP-9, in oral fluids represent strong biomarker candidates
associated especially with periodontal disease diagnosis, severity, progression, and follow-up. Additionally, they show diagnostic potential for systemic conditions, such as pregnancy, myocardial infarction, and smoking. A commercially available mouthrinse, active MMP-8 chair-side/ point-of-care lateral flow immunoassay, shows enough sensitivity and specificity to detect clinical signs of periodontitis. The current literature supports that high MMP-8 levels reflect the loss of periodontal supporting tissues rather than inflammation, representing a potentially useful sidediagnostic point-of-care oral disease biomarker, especially in periodontal diseases.