ObjectiveThis study aimed to evaluate the risk factors of radiation-induced caries by using a multiple linear regression equation and to provide the basis for the effective prevention of radioactive caries.MethodsA total of 166 patients with head and neck cancer who underwent radiotherapy were selected as subjects. The number of decayed, missing or filled surfaces were recorded. Questionnaire contents included age, sex, radiation dose, and radiotherapy techniques. Multiple step-wise regression analyses were performed to identify the risk factors of radiation-induced caries.ResultsMultiple stepwise regression analyses indicated that the main risk factors of radiation-induced caries were plaque index, radiotherapy techniques, time after radiotherapy, and radiotherapy dose.ConclusionThe awareness of dental care and caries treatment should be improved to reduce the occurrence of radiation-induced caries in patients with head and neck cancer. In addition, intensity modulated radiation therapy should be employed to decrease the radiation exposure dose received by teeth.