Dental X-rays (radiographs) are images that help your dentist identify and diagnose problems with your teeth, gums, jaw, and the tissues in your mouth. These problems don’t always show up in a regular exam. X-rays can catch issues such as infections before they get worse and even early signs of oral cancer.
How Do Dental X-Rays Work?
“X-rays are important in dentistry because although your dentist is trained to identify any abnormal tissues in the mouth, X-rays allow us to go deeper and see abnormalities that can’t be seen by the naked eye,” says Arlene Asante, DDS, dentist and owner of First Class Smiles in Bethesda, Maryland.
Dental X-rays show more than just your teeth. They help your dentist spot problems in areas that are hard to see, including:
Your sinuses. The pressure or infection here can cause tooth pain. They can also be affected by dental issues.
Between your teeth. In these spots, small cavities or damage may hide from view during a regular exam.
Your temporomandibular joint (TMJ). This may show signs of joint problems, such as pain, clicking, or trouble opening your mouth.
What Problems Can Dental X-Rays Detect?
In adults, dental X-rays can:
- Show areas of decay that may not be visible with an oral exam, especially small areas of decay between teeth
- Spot decay beneath an existing filling
- Show bone loss that happens with gum disease
- Show changes in the bone or in the root canal resulting from infection
- Help in preparing tooth implants, braces, dentures, or other things for dental procedures
- Show an abscess (an infection at the root of a tooth or between the gum and a tooth)
- Spot oral cancer
In children, dental X-rays are used to:
- Watch for decay
- Figure out if there’s enough space in your child’s mouth to fit their incoming teeth
- Tell if baby teeth are falling out in time for permanent teeth to come in properly
- Check for the development of wisdom teeth and see if any are impacted (unable to come through the gums)
- Spot other developmental abnormalities, such as cysts and some types of tumors
Types of Dental X-Rays
There are two main types of dental X-rays:
Intraoral X-rays. They place the X-ray film inside your mouth.
Extraoral X-rays. They place the X-ray film outside your mouth.
Intraoral X-rays
They are the most common type of dental X-ray. Dentists use them to:
- Find cavities
- Check the health of the tooth root and the bone around it
- Track how new teeth are coming in
- Check the overall health of your teeth and jaw
Extraoral X-rays
These images show your teeth, but their primary focus is your jaw and skull. They don’t offer as much detail as intraoral X-rays. They aren’t used for finding cavities or checking individual teeth. Dentists use extraoral X-rays to:
- Look for impacted teeth
- Check how the jaws are growing and fitting to the teeth
- Find the problems with the jaw joint (TMJ) or the bones of the face or how the teeth and jaws fit together
Types of Intraoral X-Rays
There are many types of intraoral X-rays, each of which shows different aspects of teeth.
Bitewing X-rays
These X-rays show details of your upper teeth and lower teeth in one area of your mouth. Each image captures the tooth from the crown down to the supporting bone. Dentists use bitewing X-rays to find decay between teeth. They also help spot changes in bone density caused by gum disease. Dentists may use them to check if a crown or a cast filling fits properly. They can also reveal gaps or weak spots where the filling meets your natural tooth.
Periapical X-rays
Periapical X-rays show your whole tooth — from the crown to the root tip. Each image captures the full length of the tooth. It also includes all the teeth in one section of either the upper or lower jaw. Dentists use this type of X-ray to spot problems in the root or in the surrounding bone.
Occlusal X-rays
Occlusal X-rays are larger and offer a clear view of full tooth development and placement. Each X-ray shows the entire arch of teeth in either the upper or lower jaw.
Types of Extraoral X-Rays
There are many types of extraoral X-rays that your dentist may take.
Panoramic X-rays
Panoramic X-rays show your entire mouth area — all the teeth in both the upper and lower jaws — on a single X-ray. This type of X-ray is useful for seeing the position of fully emerged as well as emerging teeth. It can also help locate impacted teeth and aid in the diagnosis of tumors.
Tomograms
They show a particular layer or “slice” of the mouth while blurring out all other layers. This type of X-ray is useful for looking at structures that are hard to clearly see, for example, because other structures are close to the structures your dentist wants to view.
Cephalometric projections
Cephalometric projections show the entire side of your head. This type of X-ray is useful for looking at your teeth in relation to your jaw and profile. Orthodontists use this type of X-ray to form their treatment plans.
Sialography
Sialography involves viewing your saliva-producing (salivary) glands following the injection of a dye. Doctors inject the dye (called a radiopaque contrast agent) into your salivary glands so they can see the organ on the X-ray film (the organ is a soft tissue that they usually can’t see with an X-ray). Dentists might order this type of test to look for salivary gland problems, such as blockages or Sjögren’s syndrome.
Computed tomography
CT scanning shows the inside of your body’s structures as a 3D image. This type of X-ray, which doctors may carry out in a hospital, radiology center, or a dental office, finds the problems in the bones of the face, such as tumors or fractures. Doctors also use CT scans to check bone for the placement of dental implants and hard extractions. This helps the surgeon avoid possible problems during and after surgery.
There’s another type of CT scan called cone beam CT, or CBCT. It also creates 3D images of your teeth and other parts of your head, face, and neck. It captures images in a single scan, and doctors use it in treatment planning.
What Is the Current Dental X-Ray Technology?
Digital imaging. This is a newer dental X-ray technique that your dentist may already have been using or may start using soon. Instead of developing X-ray film in a dark room, the X-rays go straight to a computer. Your dentist can view them on screen, store them, or print them out. There are many benefits of using this new technology:
- It uses less radiation than the typical X-ray, and there’s no wait time for the X-rays to develop — the images are available on screen in a few seconds.
- Dentists can enhance and enlarge an image many times its actual size on the computer screen, making it easier to see any problems.
- If needed, dental staff can electronically send images to another dentist or specialist. For example, to get a second opinion on a dental problem, to figure out if you need to see a specialist, or to see a new dentist (if you move).
- Software added to the computer can help dentists digitally compare current images to previous ones in a process called subtraction radiography. Using this technique, everything that is the same between two images is “subtracted out” from the image, leaving a clear image of only the portion that is different. This helps dentists easily see the tiniest changes that they may not notice with their naked eye.
Artificial and augmented intelligence. More often, dentists use artificial intelligence (machine intelligence) and augmented intelligence (human-aided machine intelligence) to support their work. They may use these technologies to:
- Analyze dental images
- Discover oral diseases earlier and with better accuracy
- Plan treatment
- Process patient data to spot patterns and forecast future oral health problems
“With AI technology, I can see things in a faster time frame,” Asante says. “That allows us to intervene at an earlier time, gives patients more options, and saves patients money.”
How Often Should Teeth Be X-Rayed?
This often depends on your medical and dental history and current condition. Some people may need X-rays as often as every six months; others with no recent dental or gum disease and who visit their dentist regularly may get X-rays only every couple of years. If you are a new patient, your dentist may take X-rays as part of the initial exam. They also help create a baseline to compare any changes over time.
Some general guidelines your dentist may follow regarding the frequency of dental X-rays is as follows:
Dental X-Ray Schedule for Children, Adolescents, and Adults
| New patients | Repeat patient, high risk or decay is present | Repeat patient, no decay, not at high risk for decay | Current or history of gum disease | Other comments | |
| Children (before the eruption of first permanent tooth) | X-rays are indicated if the teeth are touching and all surfaces cannot be visualized or probed | X-rays taken every six months until no decay is present | X-rays taken every 12-24 months if the teeth are touching and all surfaces cannot be visualized or probed | X-rays of areas where disease is seen in the mouth | X-rays to check for growth and development are usually not indicated at this age |
| Adolescents (before the eruption of wisdom teeth) | A full series of X-rays is indicated when there is evidence of dental disease or history of extensive decay | X-rays taken every 6-12 months until no decay is present | X-rays taken every 18-36 months | X-rays of areas where disease is seen in the mouth | X-rays should be taken to check for development of wisdom teeth |
| Adults with teeth | A full series of X-rays is indicated when there is evidence of dental disease or history of extensive decay | X-rays taken every 12-18 months | X-rays taken every 24-36 months | X-rays of areas where disease is seen in the mouth | X-rays to check for growth and development are usually not indicated |
| Adults without teeth | X-rays are usually not indicated unless specific dental disease is clinically present |
People who fall into the high risk category and may need X-rays taken more often include:
- Children. In general, kids need more X-rays than adults because their teeth and jaws are still forming and teeth are smaller. As a result, decay can reach the inner part of the tooth (called the dentin) quicker and spread faster.
- Adults who have had lots of dental work to replace damaged or missing teeth, such as fillings, and need to look for decay beneath existing fillings or in new locations
- People who drink a lot of sugary beverages, which can lead to cavities
- People with periodontal (gum) disease; X-rays can help check bone loss.
- People who have dry mouth — called xerostomia — due to medications (such as antidepressants, anti-anxiety drugs, antihistamines, and others) or a health condition (such as Sjögren’s syndrome, damaged salivary glands, radiation treatment to head and neck); dry mouth can cause you to form cavities.
- Smokers. The X-rays monitor bone loss resulting from periodontal disease (smokers are at higher risk for periodontal disease).
What Happens During a Dental X-Ray?
First, the dental staff should explain what type of X-rays you’re getting and why your doctor or dentist requested them. “We only take X-rays when needed; that’s a philosophy we follow,” Asante says. “Although [X-rays are] low radiation and not very toxic, we still want to be mindful of the exposure.”
Next, staff may cover you with a lead apron or thyroid collar to protect the to other parts of your body from radiation exposure. The American Dental Association (ADA) no longer suggests these protective devices, as research shows that modern digital X-ray equipment emits 80%-90% less radiation than conventional machines.
Limiting the X-ray beam to the imaging area also protects you from radiation exposure. Plus, protective devices could keep dentists from capturing precise images. The ADA guidelines apply to everyone, including children and pregnant people.
When you have a periapical or bitewing X-ray, you’ll sit in a chair, and the staff will bring the X-ray machine to your mouth. If you’re having a CBCT or panoramic X-ray, you’ll stand, and the X-ray machine will circle around you. Be sure to sit or stand as still as possible while a technician captures the images.
If you had a traditional X-ray, dental staff will develop it using chemicals. Digital X-rays are available right away on a computer. Your dentist will then review the X-rays for problems such as decay or bone loss. If needed, they would suggest a treatment plan that may include removing teeth or adding fillings.
How Safe Are Dental X-Rays?
Exposure to all sources of radiation, including the sun, minerals in the soil, appliances in your home, and dental X-rays, can damage your tissues and cells and lead to cancer. The dose of radiation you’re exposed to during a dental X-ray is very small, especially if your dentist is using digital X-rays.
Advances in dentistry over the years have led to a number of measures that lower the chance of harm linked to X-rays. But, even with safety advances, the effects of radiation add up over a lifetime. So, every little bit of radiation you get counts.
If you’re concerned about radiation exposure due to X-rays, talk to your dentist to know how often you may need X-rays and why they’re taking them.
Takeaways
Dental X-rays are a tool that helps dentists spot problems in your teeth, gums, and jaw that aren’t visible during a regular exam. They can catch issues such as cavities, infections, and bone loss early, which makes treatment easier and more affordable. X-rays are also helpful in planning procedures such as implants or braces and checking on developing teeth in children. Modern digital X-rays use less radiation than the older methods, and some dentists are also using AI to catch problems faster. While X-rays are safe, dentists use them only when needed to limit exposure to radiation.
Dental X-Rays FAQs
Can dental X-rays detect oral cancer?
Some types of oral cancer can be found using X-rays, mainly cancer of the jaw. It’s still important to get regular oral cancer screenings to spot other types of mouth cancer.
Can I have dental X-rays if I’m pregnant?
The chance of harm from an X-ray to the fetus is low. But, most dentists will take X-rays during pregnancy only when they’re needed.
How long does dental radiation stay in your body?
As dental X-rays are brief and the radiation exposure small, radiation passes through your body right away.
