Head and neck cancers are treated with radiotherapy, chemotherapy, or surgical applications. Various oral complications occur in patients who are exposed to these treatments. Complications that occur in these patients may be temporary as well as permanent. Complications such as candida infection, taste disorder, radiation caries, osteoradionecrosis, soft tissue necrosis and xerostomia can be seen in patients receiving cancer treatment in the head and neck area. The treatment of these patients is carried out in a multidisciplinary manner with branches such as radiation oncology, medical oncology, plastic surgery and dentistry. Especially, oncologists should refer patients to dentists before radiotherapy and chemotherapy. Dentists should be aware of the complications that may occur in patients who will be treated with possible radiotherapy and chemotherapy, and should have information about the dental applications to be applied.