Brain and salivary gland tumors related to prior dental radiography: implications for current practice.

Five epidemiological studies of brain, cranial meninge, and salivary gland tumor sites reviewed implicate prior dental radiography with increased risk of subtentorial intracranial meningiomas and tumors of the parotid gland. Diagnostic radiography (medical and dental) was the most important risk factor identified for parotid gland cancers; among Los Angeles County residents, about 85% of the cumulative parotid dose from diagnostic radiography came from dental examinations. Irradiation of patients during dental radiography declined substantially from 1920 to 1988; it is uncertain whether current low doses increase risk. Recommendations for exposure reduction are made.