Dental X-rays held by clips. These small X-rays show an area of a few teeth, rather than the whole jaw. This helps to reduce exposure to the damaging effect of X-rays. The X-ray at left shows three teeth (here, molars) that have been filled with a dental filling (white). This is used to fill the cavity left after the drilling out of decayed tooth material. The X-ray at centre shows a gap in the teeth where one of the two pre-molars is missing. The X-ray at right shows a dental tool (white, centre right) and an artificial crown (white, lower right) mounted on a peg. X-rays such as these are used by a dentist to assess the condition of a patient's teeth and implants.