KEY POINTS FROM THIS STUDY: 1) Intracranial meningioma is the most frequently reported primary brain tumor in the United States, accounting for 33.8% of all primary brain and CNS tumors. 2) Ionizing radiation is consistently identified as a modifiable risk factor for intracranial meningioma. The most consistent environmental risk factor identified for meningioma is exposure to ionizing radiation (IR), with relative risks from 6-fold to 10-fold reported. 3) The objective of this study was to examine the association between dental x-rays the most common artificial source of ionizing radiation and the risk of intracranial meningioma. This is the largest case-control study to date examining the correlation between dental x-rays and the risk of meningioma. 4) The sample used in this analysis included 1433 patients who had intracranial meningiomas diagnosed at ages 20 to 79 years, and 1350 controls. 5) Over a lifetime, intracranial meningioma patients were more than twice as likely as controls to report having ever had bitewing dental x-rays. Significantly elevated risk was observed across all ages with the exception of individuals aged 50 years at the time of the bitewing x-rays. 6) Regardless of the age at which the x-rays were obtained, those who received bitewing x-rays on a yearly basis or with greater frequency had an elevated risk for intracranial meningioma: * ages 10 years: 40% increased risk * ages 10 to 19 years: 60% increased risk * ages 20 to 49 years: 90% increased risk * ages 40 years: 50% increased risk 2 7) An increased risk of meningioma also was associated with panorex films taken at a young age or on a yearly basis or with greater frequency, and individuals who reported receiving such films at ages 10 years had a 4.9 times increased risk of meningioma. [Exposing children younger than 10 years of age to panorex dental xrays appears to be a very bad idea]; [Exposing anyone to yearly panorex dental x-rays also appears to be a very bad idea] 8) Regardless of the age, more frequent receipt of bitewing films was associated with increased risk of intracranial meningioma. 9) A similar elevated risk for meningioma was observed for full-mouth series among individuals who received yearly or more frequent scans at a young age. 10) Significant increases in the risk of meningioma was associated with young age at receipt of screening as well as more frequent screening, and individuals who were aged 10 years at the time of screening had an almost 5-fold increase in risk (490%). 11) Our findings suggest that dental x-rays, particularly when obtained frequently and at a young age, may be associated with an increased risk of intracranial meningioma. 12) Our findings indicate a statistically significant increased risk with both bitewing and panoramic films. Risk estimates for full-mouth films, although not statistically significant, were consistently in the same direction as for the other 2 film types. 13) The findings presented here are important, because dental x-rays remain the most common artificial source of exposure to IR for individuals living in the United States. 14) The American Dental Association’s recent statement on the use of dental radiographs highlights the need for dentists to examine the risk/benefit ratio associated with the use of dental x-rays and confirms that there is little evidence to support the use of dental x-rays to search for occult disease in asymptomatic patients or to obtain routine dental studies from all patients at preset intervals.