What part of the electromagnetic spectrum is used to take images of your teeth?

We might find that X-rays are used to take images of teeth. On the other hand, optical light can be used to take "regular" images of teeth. Both X-rays and visible light can be used to make images of teeth. The X-rays can actually see "through" the lips, cheeks and gums to create an image of the roots of teeth. Optical images show only what is on the surface.