Patients who receive radiation therapy to the head and neck are exposed to various risks and associated side effects which include the risk of radiation caries. Radiation caries represents an aggressive and rapidly progressive form of caries caused by lack and change in the composition and function of saliva , which occurs due to damage to salivary glands by radiation. Oralhealth care plays an important role in the treatment and access to patients under radiotherapy. Dentists have to establish good communication with the patient, inform the patient and also prevent unwanted side effects of radiotherapy before, during and after the rehabilitation. The prevention of radiation caries is achieved by the daily use of fluorides at home and proffesionally administered high-concentracion fluorides applied dy dentists. It is recommended that the patients under radiotherapy should brush their teeth with a soft toothbrush, using a high fluoride toothpaste, apply mouthwash with fluoride, apply fluoride gels on a daily or weekly basis and apply fluoride varnish every 2-4 months. Regular checks after completing radiotherapy are required at least two times a year. It is important that the patient continues with good oral hygiene and is still coming to regular dental checks after completing radiotherapy. It takes regular checks that should be in the beginning every month , then every two or three months. It is important that the patient after radiotherapy continues with good oral care, continues a lifetime fluoridation and is coming to regular dental checks . Otherwise, radiation caries will occur, leading to the need of extracting teeth, which can result in the development of osteoradionecrosis in patients who were undergoing radiotherapy. Fluoridation will prevent radiation caries and prevent the need for extraction and development of osteonecrosis.