Favorable response of an extensive periapical lesion to root canal treatment.

This article presents non-surgical resolution of an extensive periapical lesion of endodontic origin associated with the maxillary left lateral incisor. Clinical examination revealed an asymptomatic bony hard swelling confined to the palate, while radiographic analysis showed a lesion measuring 22 mm in diameter and nearly 389 mm(2) in area. Through apical patency, 4 ml of intracanal exudate was drained. After thorough biomechanical preparation, a calcium hydroxide/CPMC root canal dressing was applied and periodically renewed for 11 months. The exudate was eliminated at treatment onset and significant bone formation was observed at the periapical region in the following months with concomitant resolution of the cortical expansion. Complete radiographic resolution of the periapical lesion was observed two years after the root canal filling. Thus, non-surgical treatment of this supposedly cystic, extensive periapical lesion provided favorable clinical and radiographic response.