C: Systemically and periodontally healthy control group, CP: chronic periodontitis group, ALP: alkaline phosphatase, OSC: osteocalcin, sRANKL: soluble receptor activator of nuclear factor-kappaB, IL-1β: interleukine-1β, TNF-α: tumor necrosis factor-α. The gene discussed is BGLAP; the disease is chronic periodontitis.