PTGS2 and periodontal disorder: Clinical and experimental studies show that IL-17 rises in periodontal disease and is associated with the severity of PD via action on epithelial, stromal and osteoblastic cells to promote chemokine release, neutrophil recruitment, cyclooxygenase 2 and prostaglandin E2 synthesis, RANKL expression, osteoclastogenesis, and matrix metalloproteinase activity.