Dental X-rays are divided into two categories- intraoral (meaning the X-ray film is inside the mouth) and extraoral (meaning the X-ray film is outside the mouth).
Intraoral X-rays are extremely common. They provide a lot of detail and allow a dentist to discover dental issues such as cavities, check the health of roots and bone surrounding the teeth, check developing teeth, and track the general health of your mouth.
Extraoral X-rays show teeth, but their main focus is the jaw. They do not provide the detail found with intraoral X-rays and therefore are not used for detecting cavities or for identifying problems.
They are more commonly used for looking for impacted teeth, study the development of the bones in the jaw and its effect on teeth in your mouth.