Iatrogenic complications such as accidental perforation of the root or the floor of the pulp chamber may occur.

Patient was referred for root canal retreatment of the mandibular left second molar with periapical lesion evidenced through radiographic examination. During post removal, iatrogenic perforation occurred at the mesial face of the distal root. After clinical localization of the perforation and bleeding control, MTA was applied. In a second appointment, the root canal filling was removed and the chemical-surgical retreatment of the canals was performed, followed by the obturation with gutta-percha and sealer. Patient returned after three days reporting no pain. After 6 months, 3, 7 and 10 years of follow-up.

Absence of pain, normal periodontal probing and lack of radiolucent area at the region of perforation and the periapices were detected, which evidenced the successful repair of the tooth.