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Dentists use X-ray images (also called X-rays or "radiographs") to evaluate your teeth, jaw, neck, and facial bones for signs of dental problems or other issues.

These images are important components of a thorough dental exam. They provide diagnostic information that supports a visual exam and helps your dentist identify problems early and accurately. They also establish a permanent record for your dental health history.

Your dentist can detect many types of problems by taking and evaluating X-ray images. By identifying problems early, your dentist may be able to reverse conditions like tooth decay and gingivitis. At a minimum, you are far more likely to have less long-term discomfort and costs when your dentist identifies and treats your dental problems early.

In adults, X-ray images are used to reveal:

• Tooth decay, especially between teeth, which is difficult or impossible to view directly.
• Tooth decay beneath existing dental work such as fillings, inlays, onlays, crowns, and dental sealants.
• Periodontal disease.
• The effects of tooth infections on the tooth-supporting bone and root canals.
• Bone loss in the jaw.
• Jaw cysts and tumors.
• Evidence of blocked or partially blocked blood vessels which may lead to strokes.
• Abscesses
• A tooth's position and condition, which your dentist can use to plan for dental treatments such as dental implants, orthodontic treatment, or partial dentures.

In children and adolescents, X-ray images are also used to reveal tooth development, position, and orientation. They are also used to determine whether there is enough space in the mouth for permanent teeth, including wisdom teeth, to come in properly. This information will help your child's dentist determine if a tooth may need to be removed. It can also identify if your child has any congenitally missing teeth.

Types of dental X-ray imaging

There are many different types of X-ray images, and they fall into two categories, intraoral and extraoral. Your dentist will use one or more of them based on what information is needed to properly evaluate your oral health.

Intraoral X-ray images are the most commonly used. Intraoral X-ray images are taken inside the mouth using film (or for digital X-ray imaging, an electronic sensor). There are several types of intraoral X-ray images. Each shows different aspects of teeth.

• Bitewing X-ray images
• Periapical X-ray images
• Occlusal X-ray images
• Full mouth series of X-ray images

Extraoral images are taken with the film or sensor outside the mouth. They are used to detect dental problems in the jaw and skull. There are several ways to take extraoral images, including X-rays and other imaging systems.

• Panoramic X-ray images
• Cephalometric projection X-ray images
• Tomographic surveys
• Sialography
• Cone beam CT scans

Before the procedure

• Review your health status: You will share information that will help ensure that your dentist and their staff can provide safe and effective treatment, and provide appropriate post-care guidance. Get important information here: Health history and current health status.
• Visual exam: Visual exams are always recommended prior to taking X-ray images to determine if they are needed. In some cases, your dentist may determine that it's not necessary to have X-ray images taken at this time.

During the procedure

There are slightly different processes for taking the various types of X-ray images. While many of the steps below apply to all forms of images, these are the steps for the most common type of imaging (intraoral images).

• Shielding: A hygienist or X-ray technician will place a lead apron around your upper body and may place a lead collar around your neck. This shields sensitive tissues like thyroid glands and others against direct or reflected radiation.
• Taking the image:
  • X-ray imaging film or a digital imaging chip (electronic sensor) will be placed in your mouth behind the tooth or teeth to be imaged.
  • You will be asked to bite gently on a frame that holds the imaging film or chip in position.
  • The hygienist or technician will position an X-ray tube near your cheek to align with the film or imaging chip. They will then move away and stand behind a lead shield.
  • The hygienist or technician will press a button to initiate the X-ray exposure. You may hear a beep or buzzing sound. The duration of the exposure varies according to the type of image needed but typically only lasts a fraction of a second.
  • The film or chip will be removed from your mouth, and the steps repeated if necessary if images are needed in other areas of your mouth.

After the procedure

• Image processing: Your images will then be processed. Digital images are sent directly to a computer and appear within seconds. It generally takes five to ten minutes to develop film images.
• Analysis and Recording: Your dentist will analyze the images for any signs of abnormalities and include them as part of your diagnostic record. The dentist or hygienist will show you the images and make recommendations based on the findings.

Exposure to radiation

Dental X-ray imaging involves the use of ionizing radiation, which we are exposed to everyday through many types of natural and artificial sources. Ionizing radiation has a cumulative effect on human tissues and can be harmful in large enough doses over time.

The average amount of radiation most people are exposed to annually, including dental X-rays, has been shown to have little to no negative effect. Therefore, the amount of radiation exposure from dental X-ray images should not be a concern compared to the value of using them to diagnose and treat dental problems. The use of digital images (rather than traditional film) has further decreased the amount of radiation needed for dental imaging. You should discuss any concerns you may have with your dentist.

To ensure your safety from radiation, dentists and their staff are well trained in the use of X-ray machinery. They will follow patient safety procedures, like using lead aprons for the neck and body and the appropriate frequency for taking X-ray images. All X-ray imaging equipment is required to be maintained and inspected periodically by state radiation physics experts to ensure that it is functioning properly and safely.

Dentists should only take X-ray images when they expect that the additional diagnostic information will positively affect your care. To achieve this, dental practices are guided by a simple objective: to obtain the appropriate diagnostic information while keeping your radiation exposure "As Low As Reasonably Achievable." This concept is known as "the ALARA Principle."¹

There are some special considerations of which you should be aware.

• Radiation exposure may have implications for pregnancy. Talk with your dentist if you are pregnant, may become pregnant, or have concerns about any radiation exposure you may experience with dental X-ray imaging.
• Younger and smaller children may be more susceptible to the effects of radiation. Discuss any concerns you have about your child getting X-ray images.
• In men, excessive exposure to radiation has been shown to temporarily reduce sperm production, though it typically returns quickly to normal. Dental X-ray images have little to no effect on sperm production when generally accepted shielding practices and properly calibrated machinery are used.²
• Dental X-ray images may reveal an area of concern in your mouth or jaw, but your dentist may need to perform other exams or tests to fully diagnose potential issues.

The frequency of dental X-ray imaging

Just because your dental plan covers X-ray images doesn't mean you need them. The frequency with which you or your child needs images depends on many factors such as age, medical and dental history, risk for dental disease, and the access your dentist may have to previously taken images.

As an example, if you have never had tooth decay or periodontal disease, and are considered low-risk for dental disease, the length of time between dental X-ray images can typically be extended. On the other hand, some specific circumstances may require a more frequent use of X-rays. Your dentist should explain the reasons X-ray images are recommended. You should not hesitate to ask why the X-rays are considered to be necessary before they're taken.¹

Some reasons for more frequent X-ray images include:

• Evidence of periodontal disease and previous treatment.
• A history of pain or trauma.
• A family history of dental issues.
• Prior restorations such as fillings, crowns, bridges, dentures, or dental implants.
• Impacted teeth.
• Unexplained pain, swelling, bleeding, or tooth sensitivity.
• Pain or dysfunction of the jaw joint.
• Oral conditions that may affect other conditions in your body.
• Appropriate follow-up examinations after surgical, periodontal, or endodontic treatment.

There is no direct alternative to dental X-ray imaging, but there are other tools your dentist may suggest to diagnose dental issues or plan for treatment.

• Laser tooth decay detection devices. These devices do not produce a permanent record, although the readings are generally recorded and entered into your record.
• Spectroscopy devices which can measure changes in the mineral density of tooth enamel when tooth decay is detected.
• Dental photographs can be used for recording potential problems.
• Cone beam CT scans may be recommended to highlight important 3D relationships between nerves, arteries, teeth, and jawbones or to evaluate abnormalities that were identified using routine X-ray screening.

If your dentist cannot review images of the dental hard tissues and jawbones, they will not have a complete picture of your dental health status.

• Refusing bitewing X-ray images may lead to prolonged periods of undetected tooth decay, which can lead to avoidable pain, infection, and missing teeth.
• Refusing periapical X-ray images may mean fractures, infections, or other disease inside a tooth or surrounding bone go undiagnosed. This can lead to the need for additional treatments and the potential for missing teeth.
• Refusing panoramic X-ray images may lead to undiagnosed developmental conditions, such as congenitally missing teeth, or infections, cysts or tumors. If these conditions aren't diagnosed early and treated promptly, they may lead to more severe issues and treatment in the future.
• Refusing cephalometric X-ray images may overlook essential tooth and bone growth and development, or evidence of diseases or fractures.
• Refusing cone beam CT scans may mean that important 3D relationships between nerves, arteries, teeth, and jawbones are not adequately detected.

• What are the safety precautions you'll take to protect me (and my family) from excessive radiation exposure? Will you place a shielded collar on my neck to protect my thyroid glands and other sensitive tissues?
• How often do I need routine dental X-ray images such as bitewing X-ray images and a full mouth series of X-ray images?
• The ADA has guidelines on how often X-ray images should be taken based on my oral health. Why are you recommending I get them more (or less) frequently than those guidelines, even if my insurance plan covers them?
• Ask your dentist to show you the X-ray images, especially if anything of concern is detected. It is always good to be personally familiar with what is going on in your mouth. Reviewing X-ray images with your dentist can help you better understand your oral health status and treatment options.