It is common to take one or two X-rays that highlight the top of your back teeth. These X-rays reveal the upper and lower back teeth, or molars, and teeth infront of the molars, known as the premolars. The purpose of this type of X-ray is to locate any decay forming between the back teeth and helps determine the proper fit for a crown. So how did this X-ray get the name “bite-wings” you ask? This comes from the act of biting down on a wing-shaped device that holds a film in place while the X-ray is taken. Makes sense, right?