Diagnostic Significance of Peri-Implant Crevicular Fluid Biomarkers: A Narrative Review

Evaluation of peri-implant tissue health is typically based on conventional clinical parameters, including subjective and visual signs of inflammation or tissue destruction, assessment of pocket probing depth, bleeding, suppuration, and X-ray analysis of progressive bone level changes. Subsequently, the assessment of biomarkers in peri-implant crevicular fluid (PICF) has been proposed to improve the standard diagnostic protocol. PICF is a site-specific fluid that contains cells, microbes, cytokines, and other mediators. Studies have been conducted to evaluate the diagnostic significance of PICF biomarkers in the early identification of peri-implant diseases. However, this non-invasive method can be used to monitor healing processes after implant installation or soft tissue augmentation as well. Despite numerous studies, the reliability of specific biomarkers remains controversial, and their diagnostic value should be evaluated comprehensively. This narrative review aimed to compare published research on the diagnostic potential of biomarkers in PICF. After screening the scientific data, all biomarkers were grouped based on their associated biological processes. The most extensively studied categories were pro- and anti-inflammatory cytokines, tissue degradation markers, and bone remodeling factors. Despite extensive research confirming the high reliability of several cytokines, such as IL-1β, TNF-α, MMP-8, etc., many other biomarkers still require additional research to establish their specificity and sensitivity in assessing peri-implant tissues.