Radiation therapy can cause tissue and bone in the treated area to waste away. When tissue death occurs, ulcers may form in the soft tissues of the mouth, grow in size, and cause pain or loss of feeling. Infection becomes a risk. As bone tissue is lost, fractures can occur. Preventive care can lessen the severity of tissue and bone loss.

Treatment of tissue and bone loss may include the following:

• Eating a well-balanced diet.
• Wearing removable dentures or appliances as little as possible.
• Not smoking.
• Not drinking alcohol.
• Using topical antibiotics.
• Using painkillers.
• Undergoing surgery to remove dead bone or to reconstruct bones of the mouth and jaw.
• Receiving hyperbaric oxygen therapy, a method of delivering oxygen under pressure to the surface of a wound to help it heal.

Saliva is needed for taste, swallowing, and speech. It helps prevent infection and tooth decay by neutralizing acid and cleaning the teeth and gums. Radiation therapy can damage salivary glands, causing them to make 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. Tooth decay and gum disease are more likely to develop. In addition, there is some evidence that salivary glands may be damaged by certain types of chemotherapy drugs given alone or in combination. 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.

Salivary glands may not recover completely after radiation therapy ends.

Saliva production drops within 1 week after starting radiation therapy 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. The salivary glands in the upper cheeks near the ears are more affected than other salivary glands.

Partial recovery of salivary glands may occur in the first year after radiation therapy, 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.

Careful oral hygiene can help prevent mouth sores, gum disease, and tooth decay caused by dry mouth.

The following are guidelines for managing dry mouth:

• Clean the mouth and teeth at least 4 times a day.
• Floss once a day.
• Use a fluoride toothpaste when brushing.
• Apply fluoride gel once a day at bedtime, after cleaning the teeth.
• Rinse 4 to 6 times a day with a solution of salt and baking soda (mix ½ teaspoon salt and ½ teaspoon baking soda in 1 cup of warm water). Avoid foods and liquids that contain a lot of sugar. Sip water to relieve mouth dryness.

A dentist can provide the following treatments:

• Solutions to replace minerals in the teeth.
• Rinses to fight infection in the mouth.
• Saliva substitutes or medications to stimulate the salivary glands.
• Fluoride treatments to prevent tooth decay.

Tooth Decay

Dry mouth and changes in the balance of oral bacteria increase the risk of tooth decay. Meticulous oral hygiene (as described in Routine Oral Care) and regular care by a dentist can help prevent cavities.