Infected root canal treatments will be performed in two sessions with a TF Adaptive system (Protocol recommended by manufacturer (Group Control) vs. Protocol based on the initial apical file vs. XP Endo Finisher). The root canals will be completed after 14 days. Patients will record postoperative pain during the follow-up period (7 days) using a Visual analogue scale (VAS) and the change in periapical radiolucency will be assessed by periapical index (PAI) scores.