Late Complications of Head and Neck Radiation
It should be noted that salivary gland hypofunction and xerostomia may also be sequelae of other radiation regimens, e.g., radioactive iodine treatment of thyroid cancer and preconditioning total body irradiation in hematopoietic stem cell transplantation for the treatment of hematologic malignancies-although to a much lesser severity.[7,8]
Symptoms and signs of salivary gland hypofunction include the following:
- Lip dryness/crusting.
- Fissures at lip commissures.
- Atrophy of dorsal tongue surface.
- Atrophic and fragile oral mucosa.
- Difficulties in speech, chewing, and swallowing.
- Difficulty in wearing dentures (edentulous patients).
- Oral burning sensation.
- Taste disturbances.
- Increased thirst.
- Sensitivity/pain in response to spicy foods and strong flavorings.
Salivary gland tissues that have been excluded from the radiation portal may become hyperplastic, partially compensating for the nonfunctional glands at other oral sites.
Salivary gland hypofunction also alters the mechanical cleansing ability and the buffer capacity of the mouth, thereby contributing to a high risk of accelerated dental caries (cavities) and periodontal disease. Also, the progression of dental caries is accelerated by the reduction in antimicrobial proteins normally contained in saliva.
In summary, salivary gland hypofunction produces the following changes in the mouth that collectively cause patient discomfort and increased risk of oral lesions:
- Increase in salivary viscosity, with resultant impaired lubrication of oral tissues.
- Decrease in flushing/clearance of acid production after sugar exposure, resulting in demineralization of the teeth and leading to dental decay.
- Compromise of buffering capacity and salivary pH, with increased risk for dental caries and erosion.
- Increase in pathogenicity of oral flora.
- Accumulated bacterial plaque levels caused by patient difficulty in maintaining oral hygiene (caused by soreness of oral mucosa and/or muscular fibrosis/trismus).
Oral and dental management of the xerostomic patient
Patients who experience salivary gland hypofunction and xerostomia must maintain excellent oral hygiene to minimize the risk of oral lesions. Periodontal disease can be accelerated and caries can become rampant unless preventive measures are instituted. Multiple preventive strategies should be considered.
Oral hygiene protocol
Perform systematic oral hygiene at least 4 times per day (after meals and at bedtime):
- Brush teeth (if soreness of oral mucosa and trismus are present, use small ultrasoft toothbrush).
- Use a fluoridated toothpaste when brushing.
- Floss once daily.
- Apply a prescription-strength fluoride gel at bedtime to prevent caries.
- Rinse with a solution of salt and baking soda 4 to 6 times a day (½ tsp salt and ½ tsp baking soda in 1 c warm water) to clean and lubricate the oral tissues and to buffer the oral environment.
- Sip water frequently to rinse the mouth and alleviate mouth dryness.
- Avoid foods and liquids with a high sugar content. (Refer to the PDQ summary on Nutrition in Cancer Care for more information.)