An observational study in Periodontal Disease, Gingivitis and Periodontal Diseases and Biomarker Discovery and Validation, sponsored by Inonu University. Completed at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-13.
Sponsored by Inonu University · Observational
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.
Background and rationale
Periodontal disease is a common infectious and inflammatory condition of the periodontium, presenting clinically as gingivitis or periodontitis. Gingivitis is a reversible inflammation confined to the gingiva, whereas periodontitis is a chronic, progressive disease characterized by irreversible loss of periodontal attachment and alveolar bone. Although microbial biofilms containing periodontal pathogens initiate the disease, its severity and progression are largely governed by the host immune-inflammatory response.
The Hippo signaling pathway is a highly conserved regulatory network that integrates mechanical and biochemical cues to control cellular polarity, differentiation, proliferation, apoptosis, immune responses, tissue homeostasis, and organ size. Its core components include Yes-associated protein (YAP), transcriptional co-activator with PDZ-binding motif (TAZ), mammalian sterile 20-like kinase 1 (MST1), TEA domain family members (TEAD), large tumor suppressor kinase 1 (LATS1), and mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4). Upstream kinases such as MST1/2 and MAP4K4 activate LATS1/2, which phosphorylate YAP and TAZ, leading to their cytoplasmic retention or degradation and preventing TEAD-mediated transcriptional activity in the nucleus.
Preclinical evidence has implicated this pathway in mineralized tissue homeostasis of the alveolar bone and periodontal complex. Inhibition of YAP has been reported to suppress proliferation and induce apoptosis of periodontal ligament stem cells through the BCL-2 family pathway, and YAP/TAZ-deficient animal models show enhanced resorption of alveolar bone and cementum together with reduced alkaline phosphatase expression. Despite these findings, no study to date has directly evaluated the role of Hippo pathway proteins in human periodontal disease. This study was therefore designed to address that gap.
Objective and hypothesis
The study aimed to examine changes in the Hippo signaling pathway proteins YAP, TAZ, MST1, TEAD, LATS1, and MAP4K4, together with the osteogenic marker ALP and the anti-apoptotic protein BCL-2, in gingival crevicular fluid across periodontal health and disease states. It was hypothesized that the gingival crevicular fluid levels of Hippo pathway-related proteins are altered in periodontal disease and correlate with markers of bone turnover and apoptosis.
Study population and grouping
Systemically healthy adults aged 18 to 65 years who presented to the Department of Periodontology were assessed for eligibility. Participants were allocated into three groups of equal size according to the 2017 World Workshop on the Classification of Periodontal Diseases: periodontally healthy individuals, patients with gingivitis, and patients with stage 3 grade B periodontitis. Group assignment was based on probing depth, bleeding on probing, clinical attachment level, and radiographic evidence of bone loss.
Clinical examination
For all participants, Plaque Index, Gingival Index, Probing Depth, Bleeding on Probing, and Clinical Attachment Level were recorded by a single calibrated periodontist at six sites per tooth. Panoramic radiographs were used to assess alveolar bone loss.
Gingival crevicular fluid sampling
Gingival crevicular fluid samples were collected one day after periodontal examination. Participants were instructed not to eat, drink, or brush their teeth for at least two hours before sampling. Sampling sites were isolated with cotton rolls, supragingival plaque was removed, and tooth surfaces were gently dried. Paper strips were placed into the pocket and left in position for a fixed interval, and samples contaminated with blood or saliva were discarded. Fluid volume was measured electronically, and samples from each participant were pooled and stored at low temperature until analysis. Sampling sites within each group were defined according to group-specific clinical criteria.
Laboratory analysis
The levels of YAP, TAZ, MST1, LATS1, MAP4K4, TEAD, ALP, and BCL-2 were determined using commercially available enzyme-linked immunosorbent assay kits according to the manufacturers' instructions. Standard curves were generated individually for each biomarker, and results were expressed both as total amounts and as concentrations to account for differences in gingival crevicular fluid volume between health and disease states.
Analytical approach
Both total amounts and concentrations of the target proteins were compared among the three groups. Correlation analyses were performed to evaluate the relationships among the measured proteins and between these proteins and clinical periodontal parameters. Reporting protein levels in two complementary ways was intended to distinguish true biological differences from those attributable to changes in fluid volume associated with inflammation.
631 studies on the registry are indexed under Gingivitis; 107 are open to participants now.
This study's enrollment of 75 is below the median of 93 across 116 observational studies indexed under Gingivitis.
Browse Gingivitis studies →Inonu University is the lead sponsor of 394 studies on the registry; 95 are open to participants now.
Compared within Gingivitis, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Periodontal Diseases. The counts are of registry records indexed under each term, refreshed daily. How we classify →
The study population consisted of 75 systemically healthy adults aged 18 to 65 years who presented to the Department of Periodontology, Faculty of Dentistry, Inönü University, between January and May 2024. Participants were allocated into three equally sized groups according to the 2017 World Workshop classification: periodontally healthy individuals, patients with gingivitis, and patients with stage 3 grade B periodontitis. Eligible participants had at least 20 teeth excluding third molars and no systemic disease, no antibiotic use or periodontal treatment within the preceding six months, no smoking or alcohol use, and no pregnancy or lactation. Gingival crevicular fluid samples were collected from group-specific sites for quantification of Hippo signaling pathway proteins, BCL-2, and alkaline phosphatase.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Systemically healthy adults with clinically healthy periodontium, defined by probing depth of 3 mm or less, bleeding on probing below 10 percent, no clinical attachment loss, and no radiographic bone loss. Gingival crevicular fluid was collected from non-inflamed sites.
Diagnostic Test: ELISA Biomarker Analysis
Systemically healthy adults with gingival inflammation without attachment loss, defined by probing depth of 3 mm or less, generalized bleeding on probing above 30 percent, no clinical attachment loss, and no radiographic bone loss. Gingival crevicular fluid was collected from inflamed sites.
Diagnostic Test: ELISA Biomarker Analysis
Systemically healthy adults with stage 3 grade B periodontitis, defined by probing depth of 6 mm or more, clinical attachment loss of 5 mm or more, bleeding on probing of 30 percent or more, and radiographic alveolar bone loss extending to the middle or apical third of the root. Gingival crevicular fluid was collected from diseased sites.
Diagnostic Test: ELISA Biomarker Analysis
Gingival crevicular fluid samples were collected from each participant using standardized paper strips placed into the periodontal pocket for a fixed interval, and fluid volume was measured electronically. Samples were pooled per participant and stored until analysis. 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 were quantified by enzyme-linked immunosorbent assay according to the manufacturers' instructions. Standard curves were generated individually for each biomarker, and results were expressed both as total amounts and as concentrations to account for differences in fluid volume between groups.
Gingival crevicular fluid level of Yes-associated protein (YAP)
The level of Yes-associated protein (YAP) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. YAP was reported both as concentration (ng/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of transcriptional co-activator with PDZ-binding motif (TAZ)
The level of transcriptional co-activator with PDZ-binding motif (TAZ) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. TAZ was reported both as concentration (ng/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of mammalian sterile 20-like kinase 1 (MST1)
The level of mammalian sterile 20-like kinase 1 (MST1) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. MST1 was reported both as concentration (ng/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of TEA domain family member (TEAD)
The level of TEA domain family member (TEAD) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. TEAD was reported both as concentration (ng/L) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of large tumor suppressor kinase 1 (LATS1)
The level of large tumor suppressor kinase 1 (LATS1) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. LATS1 was reported both as concentration (pg/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4)
The level of mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. MAP4K4 was reported both as concentration (ng/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of B-cell lymphoma 2 (BCL-2)
The level of the anti-apoptotic protein B-cell lymphoma 2 (BCL-2) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. BCL-2 was reported both as concentration (ng/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Gingival crevicular fluid level of alkaline phosphatase (ALP)
The level of the bone metabolism marker alkaline phosphatase (ALP) in gingival crevicular fluid was quantified by enzyme-linked immunosorbent assay and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups. ALP was reported both as concentration (ng/mL) and as total amount per 30-second sampling interval.
Time frame: Baseline
Plaque Index (PI)
Plaque Index (PI) was recorded at gingival crevicular fluid sampling sites and as full-mouth values, and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups.
Time frame: Baseline
Gingival Index (GI)
Gingival Index (GI) was recorded at gingival crevicular fluid sampling sites and as full-mouth values, and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups.
Time frame: Baseline
Probing Depth (PD)
Probing Depth (PD) was recorded at gingival crevicular fluid sampling sites and as full-mouth values, and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups.
Time frame: Baseline
Bleeding on Probing (BOP)
Bleeding on Probing (BOP), expressed as a percentage, was recorded at gingival crevicular fluid sampling sites and as full-mouth values, and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups.
Time frame: Baseline
Clinical Attachment Level (CAL)
Clinical Attachment Level (CAL) was recorded at gingival crevicular fluid sampling sites and as full-mouth values, and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups.
Time frame: Baseline
Gingival crevicular fluid (GCF) volume
Gingival crevicular fluid (GCF) volume was measured electronically at sampling sites and compared among periodontally healthy, gingivitis, and stage 3 grade B periodontitis groups.
Time frame: Baseline
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Ran from Jan 2024 to primary completion in Mar 2025, 14 months.
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