The use of radiotherapy has proven to be an effective technique in the control and cure of head and neck neoplastic disease. Unfortunately, radiotherapy also has a significant negative impact on the oral health of patients and the dental care they require. For dental professionals to be valuable members of the oncology treatment team, they must have a sound understanding of the dental needs and proper treatment of these patients. As background information, a brief overview of ionizing radiation and its effect on mammalian tissue is presented. In addition, the oral complications of ionizing radiation are reviewed, and prevention and treatment protocols discussed.