Dry mouth and changes in saliva after head and neck cancer treatment

Treatments that cause dry mouth or saliva changes

Radiotherapy or chemoradiation to the head or neck can affect your salivary glands. This means that you may not make as much spit (saliva) as before and so your mouth may become dry. Your salivary glands may gradually recover after treatment finishes, but your saliva may be thicker and sticky. Some people have a dry mouth permanently.

If you feel you have too much saliva rather than too little, this may be a sign of swallowing difficulties.

If you have thick sticky saliva

Rinsing your mouth regularly can help. Your specialist head and neck team can give you advice on what type of mouth rinse to use.

Sometimes a build-up of mucus can cause coughing, especially at night. The hospital or your GP may give you a nebuliser. This is a machine that turns liquid into a fine spray. You can then breathe it in through a mask or mouthpiece. The moisture helps to loosen and break up the saliva. It may help to use the nebuliser throughout your treatment, and for several weeks afterwards. This will depend on how quickly your symptoms improve.

You could also try leaning over a steaming bowl of hot water (not boiling water) with a towel over your head. This can help loosen thick, sticky saliva. It is best to do this 4 to 5 times a day. Using a humidifier may also help make a room less dry.

If you have a dry mouth

Having a dry mouth can be uncomfortable and can affect eating, speaking and sleeping. It also makes you much more likely to get tooth decay. So it is really important to look after your teeth during and after treatment.

A warm salt water rinse can be soothing if you have a dry mouth.

To make the rinse:

  • Boil 900ml of water.
  • Let it cool to a warm temperature.
  • Add 1 teaspoon of salt.
  • Rinse the salt water gently around your mouth.
  • Spit it out and rinse your mouth with cold or warm water.

Try to do this at least 4 times a day. You should make a fresh rinse each day.

Other ways of relieving dryness

  • Carry a bottle of water with you at all times. You can take frequent sips of water or you could use a water spray instead.
  • If you cannot swallow, your nurse or doctor can give you a nebuliser (a machine that turns a liquid medicine into a fine mist or spray) to moisten your mouth and throat.
  • Try to avoid alcohol (especially spirits) and drinks that can irritate a dry mouth. This includes caffeinated drinks or citrus drinks.
  • Do not smoke, as smoking dries and irritates the mouth.
  • Ask your doctor or nurse whether you are taking any prescribed medicines that can cause a dry mouth. It may be possible to reduce the dosage or change the drug.
  • Use a lip salve to protect your lips.
  • Try using a humidifier in your bedroom at night.
  • Avoid toothpastes with foaming agents in them, as these can make your mouth dry. Foaming agents are usually an ingredient called sodium lauryl sulphate (SLS).

Eating with a dry mouth

If your mouth is dry, it can make eating more difficult. Here are some things you can do to help with eating:

  • Try to avoid foods that can irritate a dry mouth. This includes spicy, salty or hard and crunchy foods, or citrus fruits.
  • Take sips of water when you are chewing and after swallowing.
  • Eat soft, moist foods such as casseroles, soup, melon, grapes and ice cream.
  • Add moisture and fat to make food easier to manage, especially with dry and starchy foods like bread, biscuits, crackers and potatoes. For example, you could use gravies, sauces, extra oil, salad dressings, yoghurt and mayonnaise or butter to moisten foods.
  • Try rubbing a very small amount of olive or sunflower oil onto your gums just before a meal. This can make it easier to chew and move foods around the mouth.

Stimulating saliva

Chewing sugar-free gum may help stimulate saliva. Some gums (such as Spry® gum) contain xylitol, a low-calorie sweetener, which can reduce tooth decay. XyliMelts® also contain xylitol and are designed to slowly release it over a few hours to relieve dryness at night. You can buy these products online.

Some sharp-tasting sweets also stimulate saliva. Choose ones that are sugar-free to help protect your teeth.

Artificial saliva products

You can also use artificial saliva to help moisten your mouth and throat. It is designed to be the same consistency and thickness as saliva. It comes in different forms, such as:

  • gels
  • sprays
  • mouthwashes
  • pastilles
  • tablets.

It is worth trying different types to find out which one is best for you. Your doctor or dentist can prescribe artificial saliva, or you can buy it from a chemist.

The effect of artificial saliva may only last for a short time. It is best to use it just before eating. For longer-lasting relief at night, try putting the gel on your tongue and around the inside of your mouth. This may relieve dryness for up to 5 hours. If you have dentures, you can use the gel under them. This can help them feel more comfortable and stay in place. Remember to take your dentures out at night to give your mouth a break from them.

Artificial saliva with added fluoride can help to protect your teeth. But some products are acidic and can cause tooth decay. If you have your own teeth, make sure you use one that is pH-neutral. Some brands of artificial saliva may also contain animal products. This table has more information about artificial saliva products for a dry mouth.

Mouth care and preventing tooth decay

When you are coping with the effects of cancer treatments, it can be easy to forget about caring for your teeth. But this is one of the most important things you can do before and after treatment for head and neck cancers.

Saliva helps keep your mouth clean. If you have a dry mouth, you are more likely to get mouth infections, such as thrush. This can cause white patches in the mouth, soreness or a burning feeling on the tongue. It can also cause an unpleasant taste in your mouth. Tell your doctor if you have any of these symptoms. If you have thrush, they can prescribe medicine to help. If you have dentures (see below), you are more likely to get oral thrush. You should take them out at night and keep them clean.

Try to fix any rough, chipped or sharp teeth or dentures before your treatment starts. Saliva allows the tongue, lips and cheeks to slide easily over the teeth. Having smooth teeth will prevent them rubbing inside your mouth and causing any sore areas or ulcers to develop.

Saliva is also very important in protecting your teeth against decay. Having a dry mouth means you are at much higher risk of tooth decay. Even if you only have a few teeth, it is important to have a good mouth care routine. This will help keep those teeth in good condition. It will also help to reduce your risk of a rare, serious late effect of radiotherapy called osteoradionecrosis. This can affect the jawbone.

Tips for protecting your teeth

  • Have regular check-ups with a dentist or dental hygienist every 3 to 6 months.
  • Use fluoride products (see below) prescribed by your dentist.
  • Only have sugary and acidic foods and drinks at mealtimes.
  • Follow a mouth care routine agreed with your dentist or hygienist.
  • Do not smoke.
  • Check your mouth daily for ulcers, signs of tooth decay or red, white or dark patches. When you have a dry mouth, decay often happens at the top or bottom of the tooth near the gum line.
  • If you notice a change in your mouth or teeth, do not wait for your regular check-up. Go and see your dentist immediately.

Using fluoride

Your dentist or dental hygienist will advise you on how to brush your teeth and keep your gums healthy. They may also prescribe fluoride. This strengthens the hard, outer layer (enamel) on your teeth and helps protect them from decay. It can also help reduce tooth sensitivity.

You can get toothpastes, mouthwashes and artificial saliva products with added fluoride. The highest fluoride toothpastes are Colgate Duraphat® 2800ppm and Colgate Duraphat® 5000ppm. These have to be prescribed, so ask your dentist or doctor.

Your dentist may also recommend:

  • wearing mouth guards containing fluoride overnight
  • having fluoride painted on your teeth once every three months.

Cutting down on sugary and acidic foods and drinks

When you eat sugary foods, the bacteria in your mouth quickly turns the sugar into acid. This damages your teeth and gums by breaking down the enamel on the outside of your teeth. This can make your teeth more sensitive and can cause tooth decay.

Here are some tips that might help:

  • Eat and drink fewer acidic things

    This includes fizzy drinks, orange juice, oranges and tomatoes. This is because these can break down tooth enamel. The more times you eat or drink something acidic or sugary, the more acid attacks there are on your teeth. It is important to limit these foods and drinks to mealtimes, no more than four times a day.

  • Eat fewer foods that contain refined sugar

    These include chocolate, sweets, fresh fruit juice, biscuits, cakes and buns, pastries, fruit pies, dried fruit, sweet sauces, sponge puddings, breakfast cereals, ice cream, jams, honey and fruit in syrup.

  • Check labels on foods to find out if they contain sugar

    Sugar can be called other names on food labels. Look out for glucose, sucrose, maltodextrin, dextrose, lactose, caramel, fructose, maltose, toffee, molasses, honey, syrup, corn sugar and hydrolysed starch. These are all alternative names for sugars.

  • Choose sugar-free drinks

    But it is important to be aware that some can be harmful to the teeth if they contain phosphoric acid or citric acid. Fizzy sugar-free drinks are often acidic. The safest drinks for your teeth are plain milk, still water, and tea and coffee without added sugar. Sparkling water can damage teeth as it contains carbonic acid. Some people need to regain weight after treatment and may have some of these high-energy foods as part of a building-up diet. This is fine as long as you maintain good oral hygiene to limit any possible damage to your mouth and teeth.

Brushing your teeth

Following a regular mouth care routine can help to protect your teeth. You can agree this with your dentist or dental hygienist. Looking after your mouth and teeth properly is important.

Here are some tips on brushing your teeth:

  • Brush your teeth every morning and night.
  • Choose a toothbrush with a small head and soft bristles.
  • Use a high-fluoride (see above) toothpaste.
  • If you have a sore mouth or throat or mouth ulcers, choose toothpaste without an ingredient called sodium lauryl sulphate (SLS), which foams up when you brush. Sensodyne Pronamel®, BioXtra®, Oranurse® Unflavoured Toothpaste and Biotène® Fluoride Toothpaste do not contain SLS.
  • Spend 2 to 3 minutes brushing your teeth. As you brush, gently massage the gum around the base of each tooth.
  • Brush each tooth slowly and gently. Brushing your teeth gently is enough to clean plaque from a tooth without hurting your gums.
  • Move around the mouth, brushing the outside surface of each tooth. Repeat on the inside surface of each tooth. Repeat on the biting surface of each tooth.
  • After you have brushed your teeth, spit out any excess but do not rinse with mouthwash or water. The fluoride in the toothpaste stays around your teeth and keeps protecting them, especially at night.

It is also important to clean between your teeth with dental floss or interdental brushes at least once a day. A dentist or hygienist can show you the best way to do this and advise you on the best products for you.

If you wear dentures

Here are some tips to help with mouth care if you wear dentures:

  • Use a different toothbrush from the one you use to brush your teeth to clean your dentures. Also use a denture cleaning cream.
  • Clean and rinse your dentures after eating, as well as every night and morning.
  • Gently brush the inside of your mouth with a small, soft toothbrush. This is because food may collect between the cheek and gums.
  • It is important to remove any denture fixative which has stuck to the inside of the mouth. A tissue and warm water should help remove this.
  • Before you go to bed, clean your dentures and soak them in a cleaning solution recommended by your dentist. Then leave them in a glass of water overnight. This will give your mouth a rest and reduce the chance of mouth infections such as thrush.

You may wear a special type of denture called an obturator. Your dentist may advise you to keep it in and only take it out to clean it. You should follow the advice you are given.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Chris Alcock, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.