Dry mouth and changes in saliva after treatment

Radiotherapy or chemoradiation to the head or neck can affect your salivary glands, causing a dry mouth. You may have less saliva than before and it may be thicker and sticky. Having a dry mouth can be uncomfortable and can affect eating, speaking and sleeping.

The following may help:

  • always keeping a bottle of water with you and taking regular sips from it
  • using artificial saliva products to moisten your mouth
  • stimulating saliva by chewing sugar-free gum, sucking sugar-free sweets, or taking pilocarpine tablets, if prescribed by a doctor.

If your mouth is dry you are much more likely to get tooth decay. So it is important to care for your teeth during and after treatment. Your dentist or dental hygienist may advise you to:

  • have regular dental check-ups
  • follow a mouth care routine to keep your teeth and gums healthy
  • use fluoride products to protect your teeth
  • cut back on sugar and acidic foods and drinks and limit them to mealtimes.

Treatments that cause dry mouth or saliva changes

Radiotherapy or chemoradiation to the head or neck can affect your salivary glands, causing a dry mouth. Your salivary glands may gradually recover after treatment finishes. But you may have less saliva than before and it 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.

Coping with thick, sticky saliva

Using a sodium bicarbonate mouthwash may help clear thick saliva. Every three to four hours, rinse it around your mouth and spit it out. You can make the mouthwash by adding one teaspoon of sodium bicarbonate to 550ml (one pint) of cooled, boiled water. Make a fresh mouthwash each day.

The hospital or community team may give you a nebuliser. This is a machine that turns liquid into a fine mist. You can then breathe it in through a mask or mouthpiece. The moisture helps to loosen and break up the saliva. It may be helpful to use the nebuliser throughout your treatment, and for several weeks afterwards, depending on how quickly your symptoms improve.

Alternatively, leaning over a steaming basin of hot water (not boiling water) with a towel over your head can help loosen thick, sticky saliva. It is best to do this four to five times during the day. Using a humidifier may also help to make a room less dry.

I found the thick, saliva distressing. But things improved and I no longer need to drink water during the night, although I can feel dry depending on the weather.


Coping with 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 important to care for your teeth during and after treatment.

Things that can help include:

  • relieving dryness
  • treatments that stimulate saliva
  • regular mouth care.

Relieving dryness

There are several things you can do to help relieve mouth dryness. One of the simplest is to always carry a bottle of water with you. You can take frequent sips of water or you could use a water spray instead. You can buy small atomiser spray bottles from most chemists. If you cannot swallow, your nurse or doctor can give you a nebuliser to moisten your mouth and throat. Artificial saliva can also help. It is designed to be the same consistency and thickness as saliva. It comes as gels, sprays, mouthwashes, pastilles or tablets. It is worth trying different types to find out which one suits you best. 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 five hours. If you have dentures, you can use the gel under them. This can help them feel more comfortable and stay in place.

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 the different types of artificial saliva.

Here are some other things you can do to help ease symptoms of a dry mouth:

  • Be aware of foods and drinks that can irritate a dry mouth, such as spicy, salty or hard and crunchy foods.
  • Avoid alcohol (especially spirits) and caffeine, as they can also irritate a dry mouth.
  • Do not smoke – smoking dries and irritates the mouth.
  • Some prescribed medicines can cause a dry mouth. Ask your doctor or nurse whether you are taking any of these. 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 as these can make your mouth dry.

If your mouth is dry, it can make eating more difficult. Here are some tips to help:

  • Take sips of water when chewing and after swallowing.
  • Eat soft, moist foods such as casseroles, soup, melon, grapes and ice cream.
  • Use gravies, sauces, extra oil, salad dressings, yoghurt and mayonnaise to moisten foods.
  • Add plenty of moisture and fat to make food easier to manage. Dry and starchy foods such as bread, biscuits, crackers and potatoes can be difficult to eat. For example, you could add gravy to potatoes or use lots of butter on toast.

We have more information on relieving mouth dryness in our section on eating and drinking problems.

Stimulating saliva

Treatments that stimulate saliva can help if some of your salivary glands still work or if the damage to your glands is temporary.

Chewing sugar-free gum may help stimulate saliva in some people. Some of these gums, such as Spry® gum, contain xylitol, 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.

Mouth care and preventing tooth decay

Teeth can easily be forgotten when you are coping with the effects of cancer treatments. But looking after your teeth is one of the most important things you can do after treatment for head and neck cancer.

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, an unpleasant taste, soreness or a burning feeling on the tongue. Tell your doctor if you have any of these symptoms. If you have thrush, they can prescribe medicine to help. If you have dentures, you are more likely to get oral thrush. You must take them out at night and keep them clean.

Saliva is very important in protecting your teeth against decay. A dry mouth means you have a much higher risk of tooth decay. Even if you only have a few teeth, it is important to have a good mouth care routine to help keep those teeth in good condition. This will help to reduce your risk of a rare, serious late effect of radiotherapy called osteoradionecrosis. This can affect the jawbone. You can read more about osteoradionecrosis in our section on effects on the jaw after treatment.

Here are some things you can do to help protect your teeth:

  • Have regular check-ups with a dentist or dental hygienist every three to six months.
  • Use fluoride products 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.

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 such as Colgate Duraphat® 2800ppm. Colgate Duraphat® 5000ppm toothpaste is the highest fluoride toothpaste. It must be prescribed, so ask your dentist about it.

Your dentist may also recommend wearing mouth guards containing fluoride overnight or 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 turn 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.

  • Acidic things like fizzy drinks, oranges and tomatoes 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.
  • Foods that contain sugar 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 the 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 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 will be trying to regain weight after treatment and may have some of these high-energy foods as part of a build-up diet. This is fine if you maintain good oral hygiene to limit any possible damage to your mouth and teeth.

Following a mouth care routine

Following a regular mouth care routine agreed with your dentist or dental hygienist can help to protect your teeth.

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. Contact your dentist or cancer specialist if you notice anything unusual.

Brush your teeth every morning and night. Choose a toothbrush with a small head and soft bristles. Gentle brushing is enough to clean plaque from a tooth without hurting your gums. You could use an electric toothbrush with a small, rotating head (it moves in circles). Some electric brushes come with a gentle setting, and soft or sensitive brush heads are available. Spend two to three minutes brushing your teeth.

Use high-fluoride toothpaste. Most toothpaste contains an ingredient called sodium lauryl sulphate (SLS), which foams up when you brush. If you have swallowing problems, a sore mouth or mouth ulcers, choose toothpaste without SLS. Sensodyne Pronamel®, BioXtra®, Oranurse® Unflavoured Toothpaste and Biotène® Fluoride Toothpaste do not contain SLS.

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

Brushing your teeth

  • As you brush, gently massage the gum around the base of each tooth.
  • Brush each tooth slowly and gently.
  • 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. The fluoride in the toothpaste stays around your teeth and keeps protecting them, especially at night.

If you wear dentures

  • Use a different brush and a denture cleaning cream to clean your dentures.
  • 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. 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.

If you wear a special type of denture called an obturator, you may be advised to always keep this in and only take it out to clean it. Follow the advice you are given. There is more information on obturators in our section on eating and drinking after treatment.