INS and periapical periodontitis: As dominant inflammatory cells in chronic periodontitis, macrophages (M1) express and secrete a range of proinflammatory mediators such as IL-6 and TNF-a, which reduce insulin signaling and contribute to insulin resistance and affect the balance between M1 and M2 macrophages to determine the inflammatory effect.23Previous studies have demonstrated that macrophages abundantly play a crucial role in apical periodontitis development involving their activation and migration.24