How often do dentists need panoramic dental x-rays?

Problem based only: Panoramic xray is mostly for braces, implants and wisdom teeth extraction purpose, where the big picture is needed. They are not very diagnostic for checking cavities. Periapical x-rays and bitewings are more suited for such and are recommended every 6 month to 1 year.

Depends on patient: A a general rule, panoramic radiographs are taken every three to five years. However, in monitoring some conditions, a panoramic radiograph may be needed as often as once a year to a couple of times in a year. Make sure your dentist informs you as to why you would need radiographs on a different schedule other than the norm.