Gingival Crevicular Fluid Levels of Parathyroid Hormone-Related Protein, RANK Ligand, and Osteoprotegerin in Periodontal Health, Gingivitis, and Periodontitis: A Cross-Sectional Study.

Background/

Objectives

Parathyroid hormone-related protein (PTHrP) modulates the receptor activator of nuclear factor kappa B ligand (RANKL)/osteoprotegerin (OPG) system in periodontal cells in vitro but has not been measured in gingival crevicular fluid (GCF). This study compared GCF PTHrP, RANKL, and OPG across periodontal health, gingivitis, and periodontitis.

Methods

This cross-sectional study included 81 participants with periodontal health, gingivitis, or stage III grade B periodontitis (n = 27 each). GCF was collected from two interproximal sites per participant. PTHrP, RANKL, and OPG were quantified by ELISA and expressed as total amount per site and concentration. Group comparisons were repeated with adjustment for age and sex.

Results

PTHrP total amount differed between all three groups, with values of 4.26 ± 2.96, 12.45 ± 5.77, and 19.67 ± 4.59 pg/site in periodontal health, gingivitis, and periodontitis, respectively (p < 0.001). RANKL total amount did not differ among groups (median: 51.40, 51.40, and 51.78 pg/site; p = 0.977). OPG total amount was lower (median: 53.36, 46.70, and 46.70 pg/site; p < 0.001) and the RANKL/OPG ratio higher (median: 0.98, 1.10, and 1.14; p < 0.001) in both disease groups than in periodontal health. After adjustment, PTHrP and OPG differences persisted, whereas no pairwise difference in the RANKL/OPG ratio remained significant. PTHrP correlated negatively with OPG (r = -0.530) and positively with the RANKL/OPG ratio (r = 0.481; both adjusted p < 0.001).

Conclusions

GCF PTHrP total amount differed between periodontal health, gingivitis, and periodontitis, with the highest values in periodontitis. These cross-sectional findings identify an association between GCF PTHrP and periodontal status but do not establish a causal role for PTHrP in periodontal tissue breakdown.