Extensive osteolysis of the mandible following devitalization of a tooth by arsenic trioxide.

A case of progressive osteolysis of the mandible that consisted of extensive fibrosis and granulation tissue and contained the occluded inferior alveolar artery and the inferior alveolar nerve is described. Arsenic trioxide was suspected as the possible precipitating cause of the lesion, which started with an abrupt onset of paresthesia of the lower lip following its application to the mandibular second molar for devitalization.