I asked this question over a year ago. Earlier this week the New York Times’ Well Blog answered:
People who see a dentist regularly and have good oral hygiene and no current dental problems might need bitewing X-rays of molars only every two to three years to check for early cavities, said Dr. Aruna Ramesh, director of the oral and maxillofacial radiology division at Tufts University School of Dental Medicine in Boston. More extensive X-rays may be needed every three to five years to check the health of roots and adjacent bone.
The post goes on to say kids need x-rays more frequently (every year or two) because their teeth are changing more rapidly. But it doesn’t say which kinds of x-rays they needed every year or two, bitewing or “more extensive.”
My problem with all of this is that it comes off as eminence based. Are there studies that test the benefits of x-ray intervals? That said, it’s all I need to reject the annual offer of x-rays from my dentist. That’s too frequent, except possibly for kids.
What about harms? The post reassures that risk from x-rays is very small, but points to a study that found a connection to brain cancer for people with bitewing x-rays at intervals of one year or more frequent.
Exposure to some dental x-rays performed in the past, when radiation exposure was greater than in the current era, appears to be associated with an increased risk of intracranial meningioma.
The Well Blog sensibly suggests that “patients may want to inquire whether dentists are using the fastest possible exposure to minimize radiation.” Still, note to self, stay away from annual bitewings. It’s overkill.
