Traumatic injuries of teeth are a frequent occurrence and usually involve the anterior teeth of young patients. Pulpal necrosis is a frequent sequel of trauma and if microbial infection occurs, this will result in the development of a periapical lesion (Sundqvist 1976). Conventional root canal treatment is aimed primarily at eliminating these bacteria as completely as possible (Weiger et al. 2000). Treatment options to manage large periapical lesions range from non-surgical root canal treatment and/or apical surgery to extraction. Current philosophy in the treatment of teeth with large periapical lesions includes the initial use of non-surgical root canal treatment. When this treatment is not successful in resolving the periradicular pathosis, additional treatment options should be considered. Such treatment may include non-surgical retreatment to rule out morphological abnormalities or treatment inadequacies. Surgery may occasionally be required. Surgical treatment of persistent extensive periradicular lesions most often involves curettage and apical resection. However, simpler approaches such as marsupialization or tube decompression may be alternatives for large cystic lesions (Hoen et al . 1990).
Radiographic differentiation of periapical cysts and granulomas is notoriously difficult. Natkin et al . (1984) analysed the data of various studies relating radiographic lesion size to histology. They stated that with a radiographic lesion size of 200 mm 2 or larger, the incidence of cysts was almost 100%. If the lesion is separate from the apex and with an intact epithelial lining (apical true cyst, Nair 1998), it may have developed into a self-perpetuating entity that may not heal when treated non-surgically. On other occasions, a large periapical lesion may have a direct communication with the root canal system (apical pocket cyst, Nair 1998) and respond favourably to non-surgical treatment (Hoen et al . 1990). Some clinical studies have confirmed that simple non-surgical treatment with proper infection control can promote healing of large lesions (ΓalΔ± ; kan & < en 1996, Weiger et al . 2000). An awareness of root canal morphology and careful interpretation of preoperative radiographs is necessary for adequate access and infection control in endodontic therapy. This is likely to have a critical bearing on outcome. Mandibular incisors are often anatomically complex, with 45% displaying second canals (Kartal et al. 1992). Such teeth may fail to respond to treatment if important anatomy is missed. They may also fail to respond well to surgery if infection has not been controlled.
The following case report describes the endodontic treatment of traumatized mandibular incisors which were associated with a large periapical lesion.