Salivary osteocalcin as a biomarker for periodontal disease progression and treatment response: a prospective longitudinal study

Periodontitis is a chronic inflammatory disease affecting more than 1 billion people worldwide and leading to irreversible alveolar bone loss. Although salivary biomarkers are potentially non-invasive diagnostic targets, the longitudinal changes in osteocalcin (a marker of bone turnover) following periodontal therapy have been poorly described across levels of disease progression. In this prospective longitudinal study, a new multimodal method combining salivary biomarker analysis and Cone-Beam Computed Tomography (CBCT) was employed. A total of 100 patients (25 systemically healthy controls and 75 patients with periodontitis, stratified into Stages I, II, or III according to the World Workshop 2017 classification) received non-surgical periodontal therapy (NSPT). Salivary osteocalcin and clinical parameters (PPD, CAL, PI) were evaluated at baseline, 3 months, and 6 months. The sample size was estimated by G*Power software to achieve reliable power (> 90%) for detecting clinically important correlations. Baseline salivary osteocalcin levels showed a stage-dependent increase, with Stage III patients exhibiting concentrations 4.7-fold higher than those of healthy controls (28.5 ± 4.1 vs. 6.1 ± 1.9 ng/mL; p < 0.001). Temporal trajectory analysis revealed that the greatest therapeutic effect occurred within the first three months post-NSPT, with Stage III patients showing a 30.5% reduction in osteocalcin by six months. Strong correlations were observed between osteocalcin and CAL (r = 0.88, p < 0.001), with treatment-induced changes in osteocalcin significantly predicting clinical improvement (r = 0.75, p < 0.001). Salivary osteocalcin may be a valid, non-invasive biomarker of the metabolism of the periodontal bone. Early post-treatment red detection offers an important therapeutic window to optimize follow-up intervals based on treatment, and it can be incorporated into the personalized periodontal care workflow.