Dry Mouth (Xerostomia) and Saliva

Xerostomia is due to a persistently dry mouth caused by a reduction in the production of saliva.  This is not the kind of dry mouth that can be treated by drinking a glass of water.

In order to discuss the effects of xerostomia it might be helpful to first discuss the role of saliva. Saliva is produced by 3 pair of salivary glands located around the mouth.   The average saliva production is 1.5 liters per day or 45 liters per month.  Saliva is produced continuously though out the day however at different rates.  People salivate more at the smell, sight of even the thought of food and less when asleep.

Saliva plays several important functions:

  • While eating, unless food is moistened by saliva, it cannot be properly tasted or chewed and swallowed. Dry food is very difficult to swallow and it would irritate the lining of the throat.
  • When speaking saliva lubricates the oral tissues making speech easier.
  • Saliva helps start the digestive process. It is more difficult for the stomach to digest food when the food is not moistened by an adequate amount of saliva.

Saliva plays a role in the prevention of tooth decay and gum disease.  It does this in many different ways:

  • The flow of saliva helps to wash away food debris and plaque.
  • It is alkaline so it neutralizes the acids found in the mouth that cause tooth decay and tooth erosion.
  • The volume of saliva dilutes the strength of the acid lessening its effect on tooth decay and tooth erosion.
  • Saliva reduces the amount of plaque growth and calculus (tarter) formation helping to prevent gum disease.
  • The amount of calcium found in saliva can reverse early cavity formation by a process called demineralization.

When a person has a reduced flow of saliva or has xerostomia, the following effects can be seen:

  • The mouth becomes much more susceptible to gum disease and tooth decay. The dryness of the mouth also can be very uncomfortable.
  • Bad breath becomes much more common.
  • Oral infections are more frequently seen.
  • Denture wearers have much more difficulty wearing their dentures since the saliva that is needed to make the dentures stable and give them a firm seal is lacking.
  • The lips and corners of the mouth can become dry and cracked.
  • Speech, swallowing, taste and digestion of foods can be affected.

There are several causes of Xerostomia.  These can include:

  • The use of certain medication. These can include anti-depressants, antihistamines and drugs used to reduce blood pressure.
  • Mouth breathing due to an upper airway obstruction.
  • Radiation therapy to the head and neck.
  • Surgical removal of the salivary gland or glands.
  • Anxiety and fatigue.
  • Inadequate chewing needed to stimulate saliva flow when eating.

Age does not cause dry mouth.  It is caused by something else.  See above.

There are several things that can be done to help people with dry mouth.  These include stimulating the production of saliva and treating the symptoms by:

  • Vigorously chewing food to stimulate the salivary glands.
  • Eating more foods that need to be chewed more such as fruits and vegetables.
  • Chewing gum. Make sure that it’s sugarless.
  • Taking certain drugs that can increase the flow of saliva.
  • Using specialty mouth washes, lozenges and tooth pastes.
  • Sucking on sugar free and non acidic (non-citrus) hard candies.
  • Sucking on ice and sipping lots of water.
  • If the condition is a side effect of a medication that is being taken, possibly have the physician change the medication to another which does not have xerostomia as a side effect.
  • It is very important to have very good oral hygiene since the mouth is more susceptible to both dental decay and gum disease. Prescription tooth pastes and mouth washes can help protect from dental decay and gum disease.

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