Chemotherapy, radiotherapy and your teeth: dental care before, during and after cancer treatment

Why do you need a dentist before cancer treatment?

A dental visit before chemotherapy or radiotherapy makes it possible to treat sources of infection before immunity drops or the bone is irradiated. The US National Institute of Dental and Craniofacial Research (NIDCR, 2024) recommends seeing a dentist about a month before treatment starts and giving them your oncologist’s contact details.

The 2020 MASCC/ISOO guidelines on mucositis regard a dental assessment and any necessary treatment before therapy as desirable, to reduce the risk of local and systemic infections originating from the teeth. A summary by the US National Cancer Institute (NCI) adds that dental treatment before therapy can significantly reduce infectious complications.

If antiresorptive drugs, such as zoledronic acid or denosumab, are planned for treating bone metastases, a check-up before the first dose is especially important. This is described in the article on osteoporosis drugs and the dentist.

Dental treatment before radiotherapy: what needs to be done and when?

Before head and neck radiotherapy, the 2024 ISOO, MASCC and ASCO guidelines strongly recommend a dental assessment to identify and remove teeth that would increase the risk of osteoradionecrosis (radiation-induced bone death) for the rest of the patient’s life. If a tooth needs to be removed, this should happen at least 2 weeks before irradiation begins.

A two-week healing period is recommended only if it does not delay the start of radiotherapy. With a rapidly growing tumour, extractions are postponed, because cancer treatment takes priority. The steps described in the guidelines are listed below.

• The radiation oncologist gives the dentist the planned treatment area, the expected dose to the upper and lower jaw and the start date.
• The dentist examines the teeth and gums and takes X-rays, as early as possible before irradiation.
• Teeth with a poor prognosis in the radiation field, including those with moderate or severe periodontitis, are removed before radiotherapy.
• Teeth with decay or changes at the root tip, and partially erupted wisdom teeth, are considered for treatment, depending on their position and the time available for healing.
• Extractions that change the bite are done before the immobilisation mask, worn during radiotherapy sessions, is made.
• The patient is told that the risk of osteoradionecrosis lasts for the rest of their life.

How should you look after your mouth during chemotherapy?

During chemotherapy, the foundation is daily, gentle oral hygiene, because it reduces the amount of bacteria and the risk of infection. The 2026 guidelines of the American Academy of Pediatric Dentistry (AAPD) recommend brushing the teeth and tongue 2 to 3 times a day with a soft toothbrush, regardless of blood count results.

Planned dental procedures during chemotherapy are agreed with the oncologist, because they depend on current blood results. The NCI states that when the neutrophil count falls below 1,000/µl, infections become more frequent and more severe, and with platelets below 20,000/µl the gums may bleed spontaneously.

NIDCR advises avoiding sharp, hard, crunchy, hot and spicy foods, tobacco and alcohol during treatment. According to the NCI, a temperature of 38 °C or higher during chemotherapy calls for urgent contact with your cancer care team. Also report promptly any pain or ulcers that make eating or drinking difficult, heavy bleeding or rapidly increasing swelling; do not leave it until a routine dental appointment. If you have difficulty breathing or become confused, call 112, the emergency number.

Oral mucositis after chemotherapy: what helps?

Oral mucositis is redness and ulceration of the lining of the mouth that is painful, makes eating and swallowing difficult and sometimes forces a break in treatment. The NCI describes it as one of the most common side effects of chemotherapy; with conditioning treatment before a haematopoietic stem cell transplant, it usually begins 7 to 10 days after that treatment starts, according to the AAPD.

The 2020 MASCC/ISOO guidelines assess prevention methods separately for each clinical situation. The choice of method is up to the oncology team; the main recommendations are listed below, without drug names or doses.

• Daily oral hygiene protocols (brushing, flossing, bland rinses) are suggested in chemotherapy, head and neck radiotherapy and haematopoietic stem cell transplantation.
• Cooling the mouth (oral cryotherapy) for 30 minutes is recommended during bolus 5-fluorouracil, and cryotherapy is also recommended for autologous transplantation preceded by high-dose melphalan.
• Low-level laser therapy (photobiomodulation) is recommended in selected regimens, for example before haematopoietic stem cell transplantation and with head and neck radiotherapy.
• Chlorhexidine mouthwashes are not suggested for preventing mucositis with head and neck radiotherapy; they can be used when a doctor is treating an infection.
• Saline or bicarbonate of soda rinses lack strong evidence, but experts consider that they may improve hygiene and comfort.

Dry mouth and tooth decay after head and neck radiotherapy

Head and neck radiotherapy often permanently reduces saliva production, and without its protection teeth can decay very quickly, sometimes within weeks of treatment. The 2024 ISOO, MASCC and ASCO guidelines recommend that people at risk of losing saliva use prescription-strength fluoride every day (high-quality evidence), because less decay means fewer extractions later.

The University of Florida College of Dentistry describes custom fluoride trays in its patient guide: the dentist takes impressions, makes the trays and prescribes a fluoride gel for daily use, advising that fluoride be used every day for life. The same guide recommends professional cleaning every 3 to 6 months and X-rays every 6 to 12 months after radiotherapy.

For a dry mouth, NIDCR advises drinking water often, sucking ice chips, sugar-free gum or sweets and, if needed, artificial saliva, and for a stiff jaw, daily mouth-opening exercises. We cover the causes of dry mouth and how to ease it in more detail in the article on dry mouth.

Osteoradionecrosis: can a tooth be removed after radiotherapy?

A tooth can be removed after head and neck radiotherapy, but in areas of bone that received a high dose, the 2024 ISOO, MASCC and ASCO guidelines recommend first considering root canal treatment, a crown or a filling. Extraction is carried out when infections keep coming back, pain does not settle or symptoms cannot be controlled in any other way; the guidelines recommend avoiding implants in high-risk zones.

According to these guidelines, osteoradionecrosis (ORN) is exposed bone, or bone that can be felt through a pocket or fistula, or a change on an X-ray, at a previously irradiated site. The high-risk group comprises people whose jaw bone received a dose of 50 Gy or more, and the risk is increased by poor oral hygiene, oral surgery and smoking.

AAOMS (2022) reports that estimates of osteoradionecrosis after extraction in irradiated bone are similar to the risk of osteonecrosis after extraction in cancer patients treated with antiresorptive drugs, which usually falls between 1 and 5%. Before planning treatment the dentist should know the radiotherapy plan, and the guidelines do not recommend routine hyperbaric oxygen therapy before an extraction.

Cancer treatment and teeth: priorities at each stage

Dental priorities change with the stage of cancer treatment. The table summarises the recommendations of the ISOO, MASCC and ASCO guidelines (2024), MASCC/ISOO (2020), AAPD (2026) and NIDCR materials.

Children with cancer: what does the dentist look out for?

Every child should have an oral examination before immunosuppressive treatment or head and neck radiotherapy, and before a haematopoietic stem cell transplant, dental treatment is completed before immunity falls. This is what the AAPD recommends in its 2026 guidelines, postponing planned procedures until immunity has recovered.

In children, extractions are best done 2 weeks before cancer treatment begins, so that the wounds have time to heal. Regular check-ups are particularly important for children who were under 6 during treatment, because therapy can disturb tooth development.

The NCI states that disorders of tooth and facial development are a common consequence of childhood cancer treatment, and that children treated with chemotherapy before the age of 5 have a higher risk of dental abnormalities. The AAPD recommends starting or resuming orthodontic treatment after at least 2 years free of disease and once immunosuppressive drugs have been completed.

How it works at DentalBlue

At DentalBlue in Białystok, a visit before cancer treatment can include an examination, a panoramic X-ray or a CBCT scan from the clinic’s own radiology unit, and a written treatment plan that can be passed on to your oncologist. In the clinic’s price list, “Wizyta bez bólu” (visit without pain: panoramic X-ray, consultation, examination and written treatment plan) costs 300 zł, and “Fluoryzacja” (fluoride treatment) 100 zł.

Bring your oncology records with the planned dates and area of treatment. The final scope and cost are set at the consultation, and prices may change. A consultation can be booked by phone.