by Gabriella Choi
Dental X-rays (radiographs) are internal images of your teeth and jaws. Dentists use X-rays to examine structures they can’t see during a routine checkup, like your jawbone, nerves, sinuses and teeth roots. Like X-rays taken in other parts of your body, dental X-rays use electromagnetic radiation to capture images of your mouth. The radiation beam passes through your soft tissues and creates images of your teeth and bones. Dental X-rays may be traditional (taken with film) or digital (taken with digital sensors and a computer). Digital dental X-rays use 80% to 90% less radiation compared to traditional dental X-ray machines.
Dental X-rays help your dentist diagnose a wide range of oral health issues.
In adults, dental X-rays can be used to:
Show areas of decay that may not be visible with an oral exam, especially small areas of decay between teeth
Identify decay occurring beneath an existing filling
Reveal bone loss that accompanies gum disease
Reveal changes in the bone or in the root canal resulting from infection
Assist in the preparation of tooth implants, braces, dentures, or other dental procedures
Reveal an abscess (an infection at the root of a tooth or between the gum and tooth)
Cysts and some types of tumors.
In children, dental X-rays are used to:
Watch for decay
Determine if there is enough space in the mouth to fit all incoming teeth
Determine if primary teeth are being lost quickly enough to allow permanent teeth to come in properly
Check for the development of wisdom teeth and identify if the teeth are impacted (unable to emerge through the gums)
Reveal other developmental abnormalities, such as cysts and some types of tumors
Dentists also use X-rays to help determine your eligibility for treatments like dental implants, braces or dentures. X-rays help your dentist check healing after certain procedures, too, such as dental bone grafts and root canal therapy. Additionally, dental X-rays can show some types of oral cancer, particularly cancer that either started in or spread to your jaw. But X-rays can’t detect all types of mouth cancer, which is why routine oral cancer screenings are very important.
Before taking dental X-rays, a technician will place a lead apron over your chest and may wrap a thyroid collar around your neck to protect you from excess radiation. When it’s time to take the X-rays, you’ll either sit in a chair or stand in front of an X-ray machine. A technician will place the film or sensor, and then press a button to take the X-ray image. It’s important to hold as still as possible during this process so the X-ray is taken without errors.
There are two main types of dental X-rays: intraoral (meaning the X-ray film is inside the mouth) and extraoral (meaning the X-ray film is outside the mouth).
Intraoral X-rays are the most common type of dental X-ray taken. These X-rays provide a lot of detail and allow your dentist to find cavities, check the health of the tooth root and bone surrounding the tooth, check the status of developing teeth, and monitor the general health of your teeth and jawbone.
Extraoral X-rays show teeth, but their main focus is the jaw and skull. These X-rays do not provide the detail found with intraoral X-rays and therefore are not used for detecting cavities or for identifying problems with individual teeth. Instead, extraoral X-rays are used to look for impacted teeth, monitor growth and development of the jaws in relation to the teeth, and to identify potential problems between teeth and jaws and the temporomandibular joint or other bones of the face.
There are several types of intraoral X-rays, each of which shows different aspects of teeth.
Bite-wing X-rays show details of the upper and lower teeth in one area of the mouth. Each bite-wing shows a tooth from its crown to about the level of the supporting bone. Bite-wing X-rays are used to detect decay between teeth and changes in bone density caused by gum disease. They are also useful in determining the proper fit of a crown (or cast restoration) and the marginal integrity of fillings.
Periapical X-rays show the whole tooth -- from the crown to beyond the end of the root to where the tooth is anchored in the jaw. Each periapical X-ray shows this full tooth dimension and includes all the teeth in one portion of either the upper or lower jaw. Periapical X-rays are used to detect any abnormalities of the root structure and surrounding bone structure such as decay, gum disease, bone loss, etc.
Occlusal X-rays are larger and show full tooth development and placement. Each X-ray reveals the entire arch of teeth in either the upper or lower jaw. They help your dentist detect any issues in the floor or roof of your mouth. These images are helpful when diagnosing fractured or impacted teeth or evaluating the roots of your front teeth. Occlusal images can also help identify cysts, abscesses and jaw fractures. Pediatric dentists may use occlusal X-rays to evaluate developing teeth.
There are also several types of extraoral X-rays that your dentist may take.
Panoramic X-rays shows all of the structures in your mouth on a single image, including your upper and lower teeth, jaw joints, nerves, sinuses and supporting bone. This type of X-ray is useful for detecting the position of fully emerged as well as emerging teeth, can identify impacted teeth, and aid in the diagnosis of tumors.
Tomograms show a particular layer or "slice" of the mouth while blurring out all other layers. This type of X-ray is useful for examining structures that are difficult to clearly see -- for instance, because other structures are in very close proximity to the structure to be viewed.
Cephalometric projections show the entire side of the head. This type of X-ray is useful for examining the teeth in relation to the jaw and profile of the individual. Orthodontists use this type of X-ray to develop their treatment plans.
Sialography involves visualization of the salivary glands following the injection of a dye. The dye, called a radiopaque contrast agent, is injected into the salivary glands so that the organ can be seen on the X-ray film (the organ is a soft tissue that would not otherwise be seen 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, otherwise known as CT scanning, shows the body's interior structures as a three-dimensional image. This type of X-ray, which may be performed in a hospital or radiology center or a dental office, is used to identify problems in the bones of the face, such as tumors or fractures. CT scans are also used to evaluate bone for the placement of dental implants and difficult extractions. This helps the surgeon avoid possible complications during and after a surgical procedure.
How often you need to take X-rays 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 and to establish a baseline record from which to compare changes that may occur over time.
Dental X-Ray Schedule for Children, Adolescents, and Adults (by WebMD) | 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 eruption of first permanent tooth) | X-rays if the teeth are touching and all surfaces cannot be visualized or probed | X-rays taken every 6 months until no decay is present | X-rays taken every 12 to 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 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 to 12 months until no decay is present | X-rays taken every 18 to 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 to 18 months | X-rays taken every 24 to 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. |
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People who fall into the high risk category who may need X-rays taken more frequently include:
Children. They generally need more X-rays than adults because their teeth and jaws are still developing and because their teeth are smaller. As a result, decay can reach the inner part of the tooth, dentin, quicker and spread faster.
Adults with extensive restorative work, such as fillings to look for decay beneath existing fillings or in new locations
People who drink a lot of sugary beverages. The sugary environment creates a perfect situation for cavities to develop.
People with periodontal (gum) disease. X-rays can monitor bone loss.
People who have dry mouth (xerostomia) whether due to medications (such as antidepressants, anti-anxiety drugs, antihistamines, and others) or disease states (such as Sjögren's syndrome, damaged salivary glands, radiation treatment to head and neck).
Smokers. The X-rays monitor bone loss resulting from periodontal disease (smokers are at increased risk of periodontal disease).
There's a newer dental X-ray technique that your dentist already may be using or may soon be using. It's called digital imaging. Instead of developing X-ray film in a dark room, the X-rays are sent directly to a computer and can be viewed on screen, stored, or printed out. There are several benefits of using this new technology:
The technique uses less radiation than the typical X-ray and there is no wait time for the X-rays to develop -- the images are available on screen a few seconds after being taken.
The image taken, of a tooth for example, can be enhanced and enlarged many times its actual size on the computer screen, making it easier for your dentist to show you where and what the problem is.
If necessary, images can be electronically sent to another dentist or specialist -- for instance, for a second opinion on a dental problem -- to determine if a specialist is needed, or to 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 may not have been noticed by the naked eye.
Exposure to all sources of radiation, including the sun, minerals in the soil, appliances in your home, and dental X-rays, can damage the body's tissues and cells and can lead to the development of cancer. The dose of radiation you are exposed to during the taking of dental X-rays is extremely small, especially if your dentist is using digital X-rays. The radiation risk from a dental X-ray is quite small. In fact, the amount of radiation you get from a full set of dental X-rays is comparable to the amount of radiation you absorb from things like TVs, smartphones and computers, building materials like ceramic floor tiles and granite countertops, and background radiation from the sun, stars and the Earth.
Advances in dentistry over the years have led to a number of measures that minimize the risks associated with X-rays. However, even with the advancements in safety, the effects of radiation are added together over a lifetime. So every little bit of radiation you receive counts.
If you are concerned about radiation exposure due to X-rays, talk to your dentist about how often X-rays are needed and why they are being taken. While some people need X-rays taken more frequently, current guidelines require that X-rays be given only when needed for clinical diagnosis.
In extremely large doses, however, dental X-rays can be harmful and may even increase your cancer risk. That’s why you shouldn’t have X-rays more often than necessary. Your healthcare provider can help you weigh the risks vs. benefits of dental X-rays. During pregnancy, it’s safe to have X-rays of your teeth while pregnant or breastfeeding. In fact, both the American Dental Association and the American Pregnancy Association have stated that dental X-rays pose little to no risk to a fetus. Even so, most dentists avoid taking X-rays during pregnancy unless it’s absolutely necessary.
As an individual, you have the right to refuse dental X-rays. However, it’s important to understand that most dentists won’t provide services without them. If you’re concerned about radiation exposure, talk with your dentist. They can help you weigh the pros and cons of getting dental X-rays.
Dental X-rays are essential for proper oral health and maintenance. People with healthy teeth and gums usually need new X-rays every year. But you might need more frequent X-rays if you’re prone to cavities or gum disease. Dental X-rays help dentists visualize diseases of the teeth and surrounding tissue that cannot be seen with a simple oral exam. They also help the dentist find and treat dental problems early on, which can help save you money, unnecessary discomfort, and maybe even your life. Ask your dentist how often you should get X-rays to keep your teeth and gums healthy.
Sources:
https://www.webmd.com/oral-health/dental-x-rays Assessed and Endorsed by the MedReport Medical Review Board
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