Summary

• The medical term for dry mouth is xerostomia.
• Xerostomia can result from a number of factors, including the use of certain medications.
• Apart from dry mouth, symptoms may include halitosis, thirst, and difficulty eating or talking.
• Treatment depends on the severity of the condition and the individual, and may include the use of artificial saliva's or saliva stimulants.
• Untreated xerostomia will result in dental caries.

Definition

Dry mouth (xerostomia) is sometimes referred to as hyposalivation (hypo = less, salivation = secretion of saliva). If left untreated, rampant dental caries will start as soon as three months after the onset of xerostomia.

Causes

Xerostomia might be caused by the following:

Biological ageing

With ageing, the probability of experiencing dental problems increases. It is however seldom the act of growing older itself that is responsible for dental problems such as xerostomia. Rather, it the factors related to ageing, such as the consequence of diseases that the elderly are more likely to have, or the consequence of medications taken for these diseases, that are the culprits.

Certain diseases and conditions

• Rheumatoid conditions, e.g. Sjogren's Syndrome
• Dysfunction of the immune system, e.g. HIV/Aids
• Hormonal disorders, e.g. Diabetes Mellitus
• Neurological disorders, e.g. Parkinson's disease
• Prolonged illnesses, e.g. Lupus, Multiple Sclerosis
• Anaemia
• Stress

Removal or tumours of the salivary glands

Conditions that necessitate the surgical removal of salivary glands will cause immediate xerostomia.

Tumours of the salivary glands might reduce the flow of saliva block it altogether.

Functional problems

Persons with a decreased chewing ability will tend to eat softer and liquified foods. This tends to decrease the flow of saliva, since the need for saliva is less.

Radiation therapy

Head, neck and oral cancers are often treated with radiation, resulting in post-irradiation xerostomia, due to permanent damage to the salivary glands from the radiation.

Drugs or medications

This is the most common cause of diminished flow and is also most common in people older than 65. There are more than 400 drugs that have xerostomia as a side effect. Here is a list of the most common ones:

• Amphetamines
• Antianxiety drugs
• Antidepressants (tricyclics)
• Anticholinergics (atropine)
• Anticonvulsants
• Antihistamines
• Antihypertensives
• Antiparkinsonians
• Antipsychotics
• Antispasmodics
• Appetite suppressants
• Barbiturates
• Bronchodilators
• Decongestants
• Diuretics
• Hypnotics
• Muscle relaxants
• Opioid (narcotic) analgesics

Anorexia Nervosa and Bulimia Nervosa

Frequent vomiting and the use of laxatives can reduce the flow of unstimulated saliva (the saliva secreted without eating). The use of psychoactive medicines, especially antidepressants that are often prescribed for eating disorders, can contribute to dry mouth.

Menopause

Women who are going through menopause will occasionally experience a problem with gums that become dry and shiny, and that bleed easily (menopausal gingivostomatitis). Mouth dryness and a burning sensation in the mouth are common complaints. Treatments focus on excellent oral hygiene, controlling the inflammation, and even using supplements such as vitamin C and complexes.

Signs and Symptoms

The following are common signs and symptoms of xerostomia:

• Difficulty talking
• Halitosis (foul odour of the mouth)
• Frequent thirst
• Burning sensation of the tongue
• Difficulty in eating, especially dry foods
• Difficulty in wearing dentures, since the retention of dentures is dependent on saliva for adhesion
• Dry, cracked lips and corners of the mouth
• Impaired taste

Consequences 

Since saliva is the body's built-in cleansing mechanism and first line of defence against plaque, a reduction or lack of saliva will have definite effects on the oral environment as follows:

• Plaque accumulation
• Food accumulation
• Increased risk of dental caries, especially on the roots of teeth, due to acids not being neutralised by the saliva
• Difficulty in eating, swallowing and talking

Treatment

The type of treatment will depend on the severity of the xerostomia. What works for one person might not work for another, and what works today might not work tomorrow. You should try various methods to alleviate dry mouth, and keep on using the most successful methods. Various methods are listed as follows:

• Use sugar-free lozenges to coat the mouth.
• Frequently sip water, and keep water at your bedside during the night.
• Sugarless chewing-gum is a simple and effective method of increasing salivation, although it is only effective while you are chewing the gum. The use of xylitol (a sweetener that does not ferment) has been found to combat caries in people suffering from xerostomia.
• Use artificial salivas such as carboxymethylcellulose or mucin.
• Use saliva stimulants such as pilocarpine hydrochloride, but under strict supervision of your doctor.
• Use fluoride as often as possible to combat caries. The fluoride in toothpaste is a very low concentrate, and will be ineffective. Use a fluoride rinse such as 0.05% Sodium Fluoride (NaF) solution (an over-the-counter product) daily, or fluoride gels or varnishes which are routinely applied professionally.
• Dietary adjustments include avoiding tobacco and smoking, alcoholic beverages, and foods high in sugar.
• A thorough oral hygiene regime is very important. Heavy plaque accumulations will occur with dry mouth and this will lead to dental caries.

Dry mouth (xerostomia) can result in oral discomfort and can have serious consequences. If you feel you have this symptom, please see your oral health professional.

Reviewed by Dr Jeff Michelson, South African Dental Association, June 2010