RESUMO
Sodium hypochlorite is the most used irrigant in endodontics, although its toxic effect on tissue is known. Sodium hypochlorite extrusion to periapical tissue can cause complications of varying severity, from oedemas and haemorrhagic lesions to life-threatening ones due to airway compromise. Our patient attended the Oral and Maxillofacial Surgery department of the Virgen del Rocío University Hospital and was referred by his dentist after bone exposure as a result of irrigant extrusion during endodontics on tooth 14. Sodium hypochlorite caused significant bone and mucosal tissue necrosis to teeth 13-16, with communication to the maxillary sinus. Several surgical procedures were needed to perform the correct debridement of the necrotic tissue and obtain good mucous. Precautions need to be taken during the use of NaOCl to avoid spreading to surrounding tissue. In cases with open apexes and apical lesion, the use of safer irrigants should be considered as an alternative. Key words:Sodium hypochlorite, extrusion, complication, bone necrosis.