This study aimed to investigate the effect of tricalcium silicate (Bio C Temp), and calcium hydroxide (Calcicur, Voco GmbH, Cuxhaven, Germany)-based intracanal dressings on the release of RANKL/OPG, TNF-α, PGE-2 and TGF-β in periapical lesions in nonsurgical endodontic retreatment of single-rooted teeth with asymptomatic apical periodontitis. The gene discussed is TGFB1; the disease is periapical periodontitis.