Historically, arsenic trioxide (AT) was commonly used in endodontic treatment because it acts quickly and devitalizes the pulp within two days. However, it is cytotoxic to gingiva and bone. If it diffuses out of the cavity it can readily cause widespread necrosis of gingiva and bone, which can lead to osteomyelitis of the jaws. This article presents two cases of osteonecrosis of the jaws caused by leakage of AT. Case 1: A 74-yearold male was referred to our department complaining of pain of the left maxilla following extraction of his first maxilla molar on the left side by a private practitioner three months earlier. Case 2: A 39-year-old female was referred to our department complaining of impairment of sensation in the left lower lip following root treatment of her second mandibular molar on the left side by a private practitioner. AT preparation had been used in both these cases two months earlier. We performed sequestrectomy under local anesthesia in these cases.
