Dry mouth
Dry mouth, or xerostomia, can occur when the salivary glands produce too little saliva but can also result from dehydration and undernutrition.
Saliva is needed for taste, swallowing, and speech: it helps prevent infection and tooth decay by neutralizing acid and cleaning the teeth and gums. Chemotherapy and radiotherapy can damage salivary glands, causing them to produce too little saliva: the mouth is less able to clean itself, acid in the mouth is not neutralized and minerals are lost from the teeth. As a consequence, tooth decay and gum disease are more likely to develop.
Symptoms of dry mouth include the following:
- thick, stringy saliva;
- increased thirst;
- changes in taste, swallowing, and speech;
- a sore or burning feeling (especially on the tongue);
- cuts or cracks in the lips or at the corners of the mouth;
- changes in the surface of the tongue;
- difficulty wearing dentures.
Dry mouth consequences include:
- difficulty wearing dentures;
- difficulty eating.
For chemotherapy, dry mouth is a temporary acute complication and salivary glands usually return to normal after chemotherapy ends, recovering in 2 to 8 weeks. For radiotherapy, salivary glands may not recover completely after radiotherapy ends: saliva production drops within 1 week after starting radiotherapy to the head and/or neck and continues to decrease as treatment continues. The severity of dry mouth depends on the dose of radiation and the number of glands irradiated. Partial recovery of salivary glands may occur in the first year after radiotherapy, but recovery is usually not complete, especially if the salivary glands were directly irradiated. Salivary glands that were not irradiated may become more active to offset the loss of saliva from the destroyed glands.
Dry mouth may be helped or avoided by careful oral hygiene and early identification may help prevent mouth sores, gum disease, and tooth decay caused by dry mouth. Patients with head and neck cancers may be particularly affected by a dry mouth and preventative measures may not solve the problem but good oral hygiene is still important.
Source: National Cancer Institute
