- dryness of the mouth
- cracked lips, cuts, or cracks at the corners of the mouth
- taste changes
- a burning sensation of the tongue
- changes in the surface of the tongue
- difficulty wearing dental appliances (like dentures)
- difficulty swallowing fluids accompanied by an increase in thirst
Saliva is necessary for carrying out the normal functions of the oral cavity, such as taste, speech, and swallowing. Saliva provides calcium and phosphate, minerals that protect the teeth against softening. It also contains substances inhibiting the production of bacteria that cause tooth decay. In addition, saliva buffers the acids produced when leftover food particles are broken down by bacteria.
Xerostomia causes the following mouth changes that can contribute to discomfort for the patient, and an increased risk for oral lesions:
- Saliva becomes thick and is less able to lubricate the mouth.
- Acids in the mouth cannot be neutralized, leading to mineral loss from the teeth.
- There is an increased risk for cavities because the mouth is less able to control bacteria.
- Plaque becomes thicker and heavier because of the patient's difficulty in maintaining good oral hygiene.
- The acid produced after eating or drinking sugary foods leads to further mineral loss from the teeth, causing even more tooth decay.
Xerostomia in cancer patients is primarily caused by the effects of radiation therapy on the salivary glands, usually the result of radiation to the head and neck area. These changes may occur rapidly and cannot normally be reversed, especially if the salivary glands themselves are irradiated. Within one week of starting radiation treatment, the production of saliva drops and continues to decrease as treatment continues. The severity of xerostomia is dependent upon the radiation dose and how many salivary glands are irradiated. Typically, the salivary glands inside the upper back cheeks (the parotid glands) are more affected than others. Salivary glands that are not irradiated may become more active as a way of compensating for the loss of saliva from the destroyed glands.
A number of medications can cause xerostomia, including many drugs used in the management of cancer or cancer treatment side effects. Some of these are: atropine, amitriptyline, carbamazepine, diphenhydra-mine, gabapentin, haloperidol, loperamide, lorazepam, meperidine, and scopolamine, among several others.
A number of clinical trials are investigating drugs called radioprotectors, which are given at the time of radiation therapy in an attempt to prevent xerostomia. If xerostomia has already developed, there are a number of measures that may help to both alleviate the symptoms of dry mouth and prevent cavities and gum disease. These measures include:
- cleaning the mouth well at least four times per day (after every meal and at bedtime)
- rinsing the mouth immediately after every meal
- using fluoride toothpaste to brush the teeth
- sipping water frequently
- rinsing the mouth with a salt and baking soda solution four to six times per day (1/2 tsp. salt, 1/2 tsp. baking soda, and 8 oz of water)
- avoiding foods and liquids containing large amounts of sugar
- avoiding mouthwashes containing alcohol
- using moisturizer on the lips
- using saliva substitutes to help relieve discomfort
- using prescription oral pilocarpine (Salagen), which can stimulate saliva secretion from the remaining salivary glands
- applying a prescription-strength fluoride gel daily at bedtime to clean the teeth
Xerostomia usually cannot be reversed when the cause is the destruction of the salivary glands by radiation treatments. It may be reversible if related to a medication. All of the treatment measures serve to increase the level of comfort, decrease the chance for oral lesions, and reduce the occurrence of gum disease and cavities.
Cerrato, Paul L. "Managing Dry Mouth in Head and Neck Cancer." RN 63 (April 2000): 102.
"Dry Mouth from Drugs: More Than Just an Annoying Side Effect." Tufts University Health and Nutrition Letter 18 (May 2000): 3.
Hodson, D.I., et al. "Symptomatic Treatment of Radiation-induced Xerostomia in Head and Neck Cancer Patients."Cancer Care Ontario Practice Guideline Initiative April 2000. 18 July 2001 <http://hiru.mcmaster.Ca/ccopgi/guidelines/head/cpg5_5f.html>
"Oral Complications of Chemotherapy and Head/Neck Radiation—Supportive Care." CancerNet PDQ 18 July 2001<http://cancernet.nci.nih.gov>.
Deanna Swartout-Corbeil, R.N.
—The collective term for several structures in the mouth: the lips, teeth, gums, tongue, pharynx, and salivary glands.