Dental X-Ray: About This Test

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What is it?

A dental X-ray is a picture of the inside of the teeth, bones, and tissues of the mouth. It can show tooth structure, cavities, wisdom teeth, bone loss, and other things that can't be seen by sight only.

The following types of dental X-rays are commonly used. Each one gives a different view of the mouth, teeth, and surrounding area.

  • Bitewing X-rays show a single view of the upper and lower back teeth.
  • Periapical X-rays show a whole tooth, from top to bottom, along with the bones that support the root. A full-mouth series of 14 to 21 of these X-ray films is often done during a first visit to the dentist.
  • Occlusal X-rays show the roof or the floor of the mouth.
  • Panoramic X-rays give a wide view of the mouth area, including the teeth, jaws, and sinuses.

Why are dental X-rays done?

Dentists use X-rays to:

  • Find problems in the mouth, such as cavities, dental injuries, and damage to the bones that support the teeth.
  • Show teeth that are not growing in the right place or are too crowded to come out of the gums properly (impacted).
  • Find cysts, tumours, or pockets of infection (abscesses) in the mouth.
  • Check the location of permanent teeth in children who still have their baby teeth.
  • Help plan treatments like doing a root canal, filling cavities, pulling teeth (extractions), or straightening teeth with braces. X-rays are also used for planning dental implants and dentures.

What happens before the test?

  • Tell your dentist if you are or might be pregnant. If you have an X-ray, he or she will have you wear a lead apron over your belly to protect your baby from the X-rays.
  • Your dentist will tell you if you need to take out any jewellery or piercings that may get in the way of the X-ray image.
  • You may get a lead apron and a thyroid collar to wear to shield your body from X-rays. Other people in the room may wear a shield or stand behind a barrier.

What happens during the test?

  • You will bite down on a small piece of cardboard or plastic that holds the X-ray film. Or you may bite down on a small digital sensor that records a computer image. The technician may reposition the film or sensor and take several images.
  • The X-ray machine is placed by your cheek near the film or digital sensor. You may hear a faint buzz while the X-ray is being taken.

What else should you know about the test?

  • The amount of radiation used in dental X-rays is low. But there is always a slight risk of damage to cells or tissue from being exposed to any radiation. The risk of damage from the X-rays is usually very low compared with the benefit the X-rays add to having good dental care.

How long does the test take?

  • The X-ray usually takes about a minute per image. You may get more than one image during a visit.

What happens after the test?

  • X-rays are usually developed while you wait. Digital X-rays are ready on a computer right away. The dentist can talk with you about the results right after your X-rays are done.
  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your dentist if you are having problems. It's also a good idea to keep a list of the medicines you take.

Where can you learn more?

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