Effects on the jaw after head and neck cancer treatment

Radiotherapy or surgery to the head and neck area can cause jaw stiffness. A speech and language therapist (SLT) or a physiotherapist can teach you exercises to help. Chewing sugar-free gum may also help to keep your jaw moving.

If eating is difficult, you may need to eat a soft diet until things improve. A dietitian or specialist nurse can advise you more.

If your jaw is stiff, you may need to use a toothbrush with a smaller head. If you cannot brush your teeth, ask your dentist or dental hygienist for advice.

After radiotherapy there is a risk of developing a rare condition where tissue in the jawbone dies. This is called osteoradionecrosis of the jaw. Although this is rare, you can reduce the risk by keeping your mouth and teeth clean, not smoking and wearing well-fitting dentures.

Tell your dentist you are at risk before any dental treatment.

Contact your cancer doctor or dentist immediately if you feel:

  • pain, numbness or a heaviness in the jaw
  • an area of roughness on your gum
  • swelling around the gum
  • teeth becoming loose.

Jaw stiffness (trismus)

After radiotherapy or surgery to the head and neck area, the muscles that open and close your mouth may become stiff. Doctors call this trismus. You may have been given mouth exercises to do to help prevent this.

Jaw stiffness can develop a few weeks or sometimes months after treatment. The amount of stiffness varies from person to person.

An easy way to check how wide your mouth can open is to try to put three fingers vertically between your lower and upper front teeth. If you can only manage 1 or 2 fingers, you may have a stiff jaw.

Tell your doctor if you have jaw stiffness or pain, even if it is mild. You will usually be referred to a speech and language therapist (SLT) or physiotherapist for assessment and treatment. Without treatment, jaw stiffness can get more severe. So it is best to start treatment as soon as possible. Your SLT or physiotherapist will measure how wide you can open your jaw at your first appointment. They will repeat this measurement at every appointment. It will help you to see what progress you are making.

Jaw exercises

Jaw exercises can help reduce stiffness and pain. They help to stretch the tissues and strengthen the muscles in your jaw. When you do them regularly, they help to increase the amount you can open your mouth.

Your SLT, physiotherapist or restorative dentist will show you what jaw stretches to do, how long to hold each stretch for and how many times to repeat them. They may also give you aids to help you gently stretch the jaw muscles. Wooden spatulas are often used. You place the spatulas between your upper and lower front teeth for a certain amount of time each day. You increase the number of spatulas you put into your mouth over time. This will gradually stretch the jaw muscles.

There are also hand-operated devices such as TheraBite® or OraStretch®. You put these inside your mouth to gently stretch the jaw muscles.

If pain in your jaw gets worse during jaw exercises, you should stop and contact your SLT or physiotherapist for advice.

Your SLT or physiotherapist may also suggest you chew sugar-free gum to keep your jaw moving.

Other things that may help if you have jaw stiffness

If you are having difficulty chewing or swallowing because of a stiff jaw, softer foods can be easier to eat. You may be referred to a dietitian or given supplement drinks to take until this improves. We have more information about eating problems.

It is important to continue with a regular mouth care routine while your jaw is stiff. If you find it difficult to reach teeth in the back of your mouth, try using a small toothbrush. Tell your dentist or hygienist if you cannot brush your teeth because of a stiff jaw. They can give you more advice.

Changes to the jawbone – osteoradionecrosis

After radiotherapy to the head and neck, the blood supply to the jawbone may not be as good as before. Sometimes, this leads to tissue in the jawbone dying. This condition is called osteoradionecrosis or ORN.

Most people who have radiotherapy will never develop ORN. But certain things can increase the risk. These include:

  • smoking
  • having a tooth removed
  • having an infection
  • wearing badly fitting dentures, which can cause an ulcer in the gum.

If tissue in the bone dies, it may cause pain, numbness or a feeling of heaviness in the jaw. You may feel an area of roughness on your gum. Sometimes there is swelling around the gum and teeth may become loose.

Always tell your doctor or dentist if you have any of these symptoms. Remember to let them know that you have had radiotherapy to your head and neck area. They can check your mouth and arrange for you to have treatment.

Reducing the risk of osteoradionecrosis

Here are some ways to reduce your risk of osteoradionecrosis (ORN):

  • Do not smoke. Smoking affects the blood supply to the bone.
  • Look after your mouth and teeth and have a dental check-up every 6 months. Having an infection or a tooth removed can increase the risk of ORN.
  • You may need to have one or more teeth taken out after radiotherapy. It is important to see a specialist oral and maxillofacial surgeon or specialist dentist to have this done. They will plan your treatment to reduce the risk of ORN developing.
  • Wear well-fitting dentures. If they rub or are sore, do not wear them. See your dentist for advice.

How osteoradionecrosis is treated

  • You may have painkillers to relieve pain and antibiotics to treat infection.
  • Surgery is sometimes used to remove the affected tissue.
  • You may be given medicines that help.
  • It is important to continue to look after your mouth and keep your teeth clean.
  • Sometimes in severe cases of ORN, jaw reconstruction may be needed.

Research is looking at a treatment using hyperbaric oxygen (HBO) that may help the tissues around the affected area to heal. HBO treatment involves breathing in oxygen at higher concentrations than it is when it is in the air. It is unclear if this treatment is beneficial at the moment. It is only available within clinical trials. Your cancer specialist can discuss it in more detail with you.