Medical and dental experts study the use of X-rays and set limits for their safety. Your dentist should take as few as possible.
Expect to get them during a first exam after not seeing a dentist for a while. This helps check tooth and gum health. If you have gum disease, the dentist may want pictures every 6 months. For regular check-ups, it's about every 2 years, depending on your dentist's plan.
Kids have more X-rays done than adults because their teeth are changing and because they get cavities more easily.