Jaw stiffness (Trismus)

After surgery or radiotherapy to the head and neck area, the muscles that open and close your mouth may become stiff.  This is called trismus and can vary 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.

Jaw stiffness can develop a few weeks or sometimes months after treatment.  Jaw exercises can help reduce stiffness and pain by helping to stretch the tissues and strengthen the muscles in your jaw.  You’ll usually be referred to a speech and language therapist (SLT) who will show you what jaw stretches to do, how long to hold each stretch for and how many times to repeat them.  When they are done regularly, they help to increase the amount you can open your mouth. You may be given either wooden spatulas or a hand-operated devices such as TheraBite® to help you gently stretch the jaw muscles.   Jaw stiffness can get more severe so it’s best to start treatment as soon as you are advised by your specialist head and neck team.

Changes to the jawbone (osteoradionecrosis)

Following radiotherapy to the head and neck area, the blood supply to the jawbone can be reduced. Sometimes this can lead to part of the tissue in the jawbone dying. This is called osteoradionecrosis or ORN.

Most people who have radiotherapy will never develop ORN.  However, 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 dies in the jawbone, it can cause symptoms such as numbness, pain or swelling in the gums.

Sometimes there is swelling around the gum and teeth may become loose. It is important to tell your dentist or doctor if you are experiencing any of these symptoms.