Radiation therapy (RT) to the head and neck can cause adverse effects to the oral cavity and may lead to both acute and chronic complications which can be minimised through optimal dental management. Complications include mucositis, xerostomia, dysgeusia, trismus, dental caries, and osteoradionecrosis.r An oral care routine aims to prevent, reduce and treat side effects associated with RT in order to avoid breaks in the patient’s treatment and to promote maintenance of good oral health after treatment.r
Changes in vascularity and the cellularity of tissue can lead to hypoxia, hypocellularity and hypovascularity of irradiated soft tissue and bone. These changes can lead to the disruption of normal salivary function, tissue breakdown, and development and/or progression of periodontal disease.r The decrease in saliva production (hyposalivation) and changes in its chemical composition can alter the microbial flora of the mouth and increase the risk of infection and dental caries. A reduced salivary flow may lead to compromised nutritional status and anorexia.
Incidence rates vary based on patient and treatment related risk factors (e.g. pre-existing dental problems, radiation dose, poor oral hygiene). It is reported that dental caries occurs in approximately 29% of head and neck cancer patients after completion of RT.r The risk of developing dental caries within two years of head and neck irradiation is approximately 37%.r While most oral complications of head and neck radiation are unavoidable, some are preventable.
Acute oral complications can occur within 2-3 weeks of starting head and neck RT (e.g. xerostomia), or may be present from surgery (e.g. trismus). Radiation related caries and other dental hard tissue changes can develop within the first 3 months following radiation treatment, while other chronic complications such as osteoradionecrosis of the jaw can take years to develop.r Some of these complications such as xerostomia may be permanent.
Predisposing factors for oral complications include patient, tumour and treatment related factors.
Patient related factors:
- tobacco use
- poor oral hygiene
- poor periodontal status
- alcohol consumption
- co-morbidities (e.g. diabetes mellitus type 2)
- advanced age
- poor nutritional statusr
- poorly fitting dentures
- oral prosthesis
Tumour related factors:
- primary site (i.e oropharynx or oral cavity)
- advanced stage tumours.
Treatment related factors:
- higher prescribed doses of radiation and subsequent dose to organs at risk, such as salivary glands and dental structures (mean radiation doses of >26 Gy to one parotid gland are associated with clinical hyposalivation)rr
- concurrent chemotherapy.