Mouth problems and taste changes

Older man with a sore mouth

Drug therapies like chemotherapy and targeted therapies and radiotherapy to the head and neck area can affect your mouth in different ways:

Mouth sensitivity / sore mouth 

Your mouth or gums may get sore. You may also get little ulcers may on your tongue, gums and inside your cheeks (mucositis).  Your mouth may be more sensitive to hot, cold, acidic or spicy food as well.

How is it treated?

There are many mouthwashes, gels and medications such as painkillers, which your doctor can prescribe for you. If you have an infection your doctor may prescribe an antibiotic. 

What can I do?

  • Keep your teeth, gums and mouth very clean, as this will help to control the soreness and reduce the risk of a mouth or throat infection.
  • Brush your teeth regularly with a small, soft toothbrush, especially after meals and before bedtime. It may be helpful to soften the brush in warm water before brushing. 
  • Use a mild fluoride toothpaste only.
  • Use a mouthwash regularly if prescribed for you. You can also make your own using 1 level teaspoon of salt or baking soda (soda bicarbonate) dissolved in half a litre of warm water
  • Avoid toothpicks
  • If you have dentures, remove them every night and if your gums are sore.
  • Use special mouthwashes to keep your mouth clean, fresh and to ease mild soreness or pain. Only use mouthwashes recommended by your dentist, radiation therapist or nurse. Some mouthwashes contain alcohol and are too harsh.
  • Sip cool water during the day. Add ice cubes to keep it cool.
  • Use a lip balm to keep your lips moist.
  • Avoid eating hot, spicy or very cold food and drink and food that might irritate your mouth like spices, garlic, onion, vinegar or very salty or sugary foods.
  • Avoid citrus drinks like lemon, orange or grapefruit.
  • Avoid food that might be hard to eat like crusty bread, crispy bacon, toast or crisps.
  • Avoid alcohol (especially spirits) and tobacco as they can irritate the lining of your mouth and throat. They can also make side-effects more severe. 
  • If you need teeth pulled (extracted), tell your doctor.
  • Visit your dentist at least every 6 months.
     

Dry mouth (xerostomia – “zero-sto-mee-a”) 

You may notice that your mouth and throat feel dry all the time. This is because treatment can cause the salivary glands to make less saliva (spit) than usual.

You may also find that saliva can become thick and stringy after radiotherapy, making swallowing and speech a little difficult too. The dryness may improve with time but can be permanent. 

What can I do?

  • Carry a water bottle with you and drink water throughout the day to keep your mouth moist.
  • Use sauces or gravy to make food moist and easier to swallow and avoid very dry foods like crackers.
  • Keep your lips moist with aqueous cream. 
  • Ask your doctor about artificial saliva products
  • Sugar-free chewing gum can help to stimulate saliva.
  • Smoking can make a dry mouth worse, so try to give up or cut down. 
  • If you have green or yellow mucus, tell your doctor. He or she may want to treat you with medication.

Problems with your teeth

If your mouth is dry you will need to take special care of your teeth. They will be more at risk of decay because of the lack of saliva. Decay can happen very quickly and can cause your teeth to break.

If you are likely to develop dental problems, a dental specialist will check your progress during radiotherapy. After the course has finished, you will need to have regular dental check-ups (every 4–6 months).

What can I do?

  • Avoid sucking sugary sweets when your mouth feels dry as it increases your risk of tooth decay. It is better to use water or sugar-free chewing gum or sweets. 
  • Avoid sugary foods and look for the ‘hidden sugars’ on the labels.
  • Fluoride products can help to help prevent decay. Your doctor will give this to you. This can be in the form of a mouthwash, special toothpaste or applied in a special gum shield made by your dentist.
  • If you decide to have any dental work after radiotherapy, do tell your dentist that you have had radiotherapy. It is very important to avoid having teeth taken out (extractions) after radiotherapy, as your gums may not heal well afterwards or you may get a bone infection called osteoradionecrosis (ORN). 

Taste changes

Some cancer treatments like some chemotherapy drugs or radiotherapy can affect the taste buds in your mouth. You may find that food tastes bland, salty, metallic or like cardboard. If this happens, you may lose interest in food.

Your normal taste should come back after treatment has ended, but it may take some time. We have more information on eating problems and weight loss

What can I do?

  • If your appetite is poor, ask your nurse or radiation therapist to refer you to a dietitian who will check your weight and give you further advice. 
  • Eating little and often can help to keep your strength up. You can also supplement your meals with build-up drinks. 
  • Use herbs and seasonings to add flavour to your food.
  • Marinate your food if you have problems tasting food.

Voice changes: Radiotherapy can cause make your voice hoarse for a time. Rest your voice as much as possible and avoid smoky places. A speech and language therapist can advise you on voice exercises to help.

Sore throat 

Your throat may be red and sore. Sometimes eating food may become difficult and swallowing painful. 

Your doctor or dietitian will advise you on how to change your diet to make eating more comfortable.

You may need to be fed by a nasogastric tube or PEG tube for a short while if you’re not able to eat. 

Mouth stiffness (trismus)

Sometimes radiation to your head and neck can cause a stiffness in certain facial muscles. This is called trismus. The stiffness can prevent you opening your mouth and jaw fully. You will be shown some simple mouth-opening exercises to keep your mouth as flexible as possible. These should be done at least twice every day. 

A speech and language therapist may also provide other ways to help. For example, you can check your facial muscles by doing the ‘3 finger test’ – turn your hand sideways and see if you can open your mouth wide enough to fit 3 fingers in. You may also be advised to use an exercise device called a TheraBite®.

Osteoradionecrosis (ORN)

After radiotherapy your jaw bone can have less blood supply and not heal so well. If the bone is injured by surgery, tooth extractions or denture irritations, a condition called osteoradionecrosis (ORN) can develop. It is much better to keep your teeth in good condition and to treat any tooth decay (cavities) quickly if they occur.

If a tooth has to be taken out after radiotherapy, you should see a dentist who is used to dealing with patients who have had radiotherapy. The tooth will need to be removed carefully and extra precautions will be taken to prevent infection, such as prescribing antibiotics. 

Tell your doctor or dentist immediately if you develop any problems with your teeth or gums, or swelling, pain, heaviness or numbness of your jaw.

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