Hippo Signaling Pathway Proteins in Gingival Crevicular Fluid of Individuals With Periodontal Disease

Periodontal disease is a chronic inflammatory condition of the tooth-supporting tissues in which the host inflammatory response drives the destruction of alveolar bone and periodontal attachment. The Hippo signaling pathway is a conserved regulatory network that controls cell proliferation, apoptosis, and bone homeostasis, but its role in human periodontal disease remains unknown. This observational, case-control study compared the levels of Hippo signaling pathway proteins (YAP, TAZ, MST1, TEAD, LATS1, MAP4K4), the anti-apoptotic protein BCL-2, and the bone metabolism marker alkaline phosphatase (ALP) in gingival crevicular fluid across 75 systemically healthy participants grouped as periodontally healthy, gingivitis, or stage 3 grade B periodontitis. The aim was to determine whether these proteins are differentially expressed across periodontal health and disease states and whether they correlate with markers of apoptosis and bone metabolism.

Inclusion Criteria: * Systemically healthy individuals aged 18-65 years * Non-smokers or smoking cessation more than 5 years ago * Healthy group: No history of periodontal disease, ≥20 teeth, probing depth (PD) ≤3 mm at all sites, bleeding on probing (BOP) \30% of teeth affected by periodontal disease, PD ≥6 mm, clinical attachment loss (CAL) ≥5 mm, vertical bone loss ≥3 mm, Class II or III furcation involvement, radiographic alveolar bone loss extending to the middle third or beyond (≥33%), bone loss-to-age ratio between 0.25 and 1.00 Exclusion Criteria: * Periodontal treatment or antibiotic use within the past 6 months * Fewer than 20 teeth (excluding third molars) * Presence of any systemic disease * Current smoking or cessation within the past 5 years * Use of immunosuppressive medication * Alcohol consumption * Regular medication use * Pregnancy or lactation * Need for antibiotic prophylaxis prior to dental procedures * Prosthetic restorations on the teeth selected for sampling