IL6 and periapical periodontitis: The cellular events that mediate tissue destruction and bone resorption in patients with apical periodontitis have largely been attributed to the release of inflammatory cytokines such as prostaglandin E2 (PGE2), tumor necrosis factor-β (TNF-β), IL-1β, interleukin-2 (IL-2) and interleukin-6 (IL-6) [13, 14] in the periapical tissues, secondary to tooth infection.