Effects on the jaw after 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 relieve this. Chewing sugar-free gum may also help.

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

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. 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 one or two 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.

How widely you can open your jaw will be measured at your first appointment. This measurement will be repeated 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 they are done 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 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 and so gradually stretch the jaw muscles.

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

If pain in your jaw gets worse during jaw exercises, stop doing them 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 you can chew better. You can find more information about eating problems in our section on eating and drinking.

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 or chemoradiation to the head and neck, the blood supply to the jawbone may not be as good as before. Sometimes, this may lead 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, wearing badly-fitting dentures, having an infection or having a tooth removed.

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. Do not forget to mention you were treated with radiotherapy. 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:

  • Do not smoke. Smoking affects the blood supply to the bone.
  • Look after your mouth and teeth. Having an infection or a tooth removed can increase the risk of ORN. You can learn more about looking after your mouth and teeth in our section on dry mouth and changes in saliva after treatment.
  • If you 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 also be given medicines that help healing.

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 oxygen at higher concentrations than is found in the air. It is unclear if this treatment is beneficial at the moment and it is only available within clinical trials. Your cancer specialist can discuss it in more detail with you.