Dry mouth

Dry mouth happens when the salivary glands don't make enough saliva to keep the mouth moist. Saliva helps break down food in the mouth. It washes away food particles and acids that are left in the mouth after you eat. Saliva also helps maintain healthy levels of bacteria in the mouth. If there is not enough saliva, bacteria can grow too quickly and cause sores, infections, gum disease and cavities. Dry mouth can also make it difficult for you to eat and swallow.

Dry mouth may also be called xerostomia.

Causes

Dry mouth can be caused by:

  • radiation to the head, neck or mouth (most common cause)
  • surgery that removes the salivary glands (such as for salivary gland or oral cancer)
  • chemotherapy
  • allergy medicines, antidepressants, diuretics and some pain medicines
  • dehydration (from not eating or drinking enough or from losing too much fluid from diarrhea or vomiting)

Dry mouth usually develops in the first 2 to 3 weeks of radiation therapy. It may slowly improve after radiation therapy to the head and neck is finished, but sometimes it can be permanent.

Surgery that removes the salivary glands will cause an immediate and permanent dry mouth.

Dry mouth caused by chemotherapy is usually temporary. Saliva usually returns to normal 2 to 3 weeks after treatment ends.

Symptoms

Symptoms of dry mouth can vary depending on their cause and other factors. Symptoms include:

  • sticky, dry feeling in the mouth or throat
  • thick, stringy saliva
  • burning feeling in the mouth
  • dry, cracked lips and tongue
  • increased thirst
  • taste changes
  • problems chewing, tasting or swallowing
  • speech problems
  • problems with your dentures
  • mouth sores or infections
  • cavities

If symptoms get worse or don't go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.

Talk to your dentist

Chemotherapy or radiation therapy can increase the risk for infection or bleeding from dental procedures. Talk to your dentist and healthcare team about having your teeth cleaned and cavities repaired before treatment starts.

People receiving radiation therapy to the head and neck area are usually seen by a dentist about 2 to 4 weeks before treatment starts. The dentist will do a full oral exam and any dental work needed. The dentist can also suggest ways to help prevent or manage problems with the mouth, teeth and jawbone that can happen with radiation therapy or chemotherapy.

Radiation therapy to the head and neck area can increase the chance of developing cavities or tooth decay. Ask the dentist or hygienist about using a fluoride rinse or gel to help prevent tooth decay.

Have regular dental checkups after cancer treatment. Talk to your dentist about other ways to prevent tooth decay and to help take care of your teeth, gums and mouth.

Managing dry mouth and its effects

Once the extent and cause of dry mouth is known, your healthcare team can suggest ways to manage it. You can try using:

  • a room humidifier at night
  • acupuncture
  • artificial saliva products or medicines to stimulate the salivary glands to make saliva

You can also try the following to help manage other problems that dry mouth may lead to.

Nutrition

Dry mouth can make it hard for you to eat and swallow. Try the following to help you maintain good nutrition:

  • Carry a bottle so it is easy to sip water, juices and other fluids frequently throughout the day.
  • Suck on ice chips, sugarless candies or popsicles.
  • Sip water during meals and take sips between bites of food.
  • Eat soft foods that are cool or at room temperature.
  • Use cream, milk, broth, gravy or sauces to moisten foods.
  • Drink commercial nutritional supplements or milkshakes.
  • Limit drinks with caffeine, such as coffee, tea and some soft drinks.
  • Avoid dry, coarse or hard foods.
  • Limit salty, acidic or spicy foods.
  • Avoid alcohol (including store-bought mouthwashes).
  • Try to stop smoking or chewing tobacco.

Follow a mouth care program

Following a mouth care program before and after cancer treatment helps to manage sores and infections. A mouth care program should include the following:

  • Clean your mouth and teeth at least 4 times each day.
  • Brush your teeth, tongue and gums after meals and before bedtime.
  • Use a very soft (such as extra soft) toothbrush and fluoride toothpaste.
  • Soften the toothbrush bristles in warm water before use.
  • Clean toothbrushes well after each time you brush your teeth.
  • Use a new toothbrush after a cold or mouth infection.
  • Get a new toothbrush every few months.
  • Gently floss each day to remove plaque.
  • Keep dentures clean and change denture solution daily.
  • Use a lip balm to keep your lips moist.

Your healthcare team will give you instructions on how to rinse your mouth. They will suggest what to use, how often to use it and when to use it (such as after meals and before bed). The type of mouth rinse you use may be based on:

  • the type of treatment you have
  • the taste of the rinse
  • what you prefer

There are many different recipes for mouth rinses, so check with your healthcare team. Different cancer treatment centres may recommend different ingredients or different amounts of salt or baking soda. Some healthcare professionals may suggest that you rinse your mouth with plain water after using a mouth rinse. Avoid mouthwashes that contain alcohol because these can dry and irritate the mouth.

Make a fresh supply of mouth rinse to use each day. Some examples are:

  • salt solution (saline) rinse: 5 mL (1 tsp) of salt in 250 mL (1 c) of water
  • baking soda rinse: 5 mL (1 tsp) of baking soda in 250 mL (1 c) of water
  • salt and baking soda rinse: 5 mL (1 tsp) of salt and 5 mL (1 tsp) of baking soda in 1 L (4 c) of water

Expert review and references

  • Understanding chemotherapy: a guide for patients and families. American Cancer Society. American Cancer Society. American Cancer Society; 2013.
  • Understanding radiation therapy: a guide for patients and families. American Cancer Society. American Cancer Society. American Cancer Society; 2013.
  • Dry mouth or xerostomia. American Society of Clinical Oncology (ASCO). Cancer.Net. Alexandria, VA.: American Society of Clinical Oncology (ASCO); 2009.
  • Haas ML . Radiation therapy: toxicities and management. Yarbro, CH, Wujcki D, & Holmes Gobel B. (eds.). Cancer Nursing: Principles and Practice. 7th ed. Sudbury, MA: Jones and Bartlett; 2011: 14: 312-351.
  • Common side effects of chemotherapy. Janes-Hodder, H. & Keene, N. Childhood Cancer - A Parent's Guide to Solid Tumor Cancers. 2nd ed. O'Reilly; 2002: 16: pp260-282.
  • Side effects of treatment. Kline, N. E. (Ed.). Essentials of Pediatric Oncology Nursing: A Core Curriculum. 2nd ed. Association of Pediatric Oncology Nurses; 2004.
  • Maher, K . Xerostomia. Yarbro, C. H., Frogge, M. H. & Goodman, M. Cancer Symptom Management. 3rd ed. Sudbury: Jones and Bartlett Publishers; 2004: 12: pp. 215-230.
  • Mouth sores and dry mouth. National Childhood Cancer Foundation & Children's Oncology Group. CureSearch. Bethesda, MD: