Osteoradionecrosis (ORN) of the jaws is a self–progressive process of bone destruction and is one of the most serious oral complications of radiation therapy to head and neck. Endodontic treatment plays a vital role in patients submitted to radiotherapy, both for the control of pain symptoms in teeth with acute pulpitis, and for the prevention of osteoradionecrosis lesions that might develop if tooth extractions are performed.