Posts for tag: x-rays
X-ray imaging is a routine part of a child's dental care — and it undeniably makes a difference in preventing and treating dental disease. It's so routine, we can easily forget they're being exposed to an invisible form of electromagnetic radiation.Â And just like other sources of radiation, too much x-ray exposure could increase the risk of cancer.
But while it's possible for your child to be over-exposed to x-rays, it's highly unlikely. That's because healthcare professionals like dentists adhere to a standard known as ALARA when considering and administering x-rays. ALARA is an acronym for “as low as reasonably achievable.” In other words, we only want to expose a patient to the lowest and safest levels of x-ray dosage and frequency that will achieve the most benefit.
To achieve that standard, professional dental organizations advocate the use of x-rays only after a clinical examination of the patient, as well as a thorough review of their medical history for any usage of x-rays for other conditions. If x-rays are warranted, we then take further precautions to protect the patient and staff, and only use the type of x-ray application that's absolutely necessary. For most children that will be a set of two or four bitewing radiographs, which are quite effective for detecting decay in back teeth.
This dosage of radiation in a session of bitewing radiographs is roughly a fifth of the background radiation in the environment a child may be exposed to every day. By spacing these sessions at least six months apart, we're able to achieve a high level of decay detection at a safe and reasonable amount of x-ray exposure.
On top of that, the digital advances in x-ray imaging have reduced the amount of radiation energy needed to achieve the same results as we once did with film. These lower exposure levels and the ALARA standard helps ensure your child's exposure to x-rays will be well within safe limits.
If you would like more information on the use of x-rays with children, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “X-Ray Safety for Children.”
It's difficult to measure how x-ray imaging has transformed dentistry since its use became prominent a half century ago. As equipment and methods standardized, the technology revolutionized the way we diagnose tooth decay and other mouth-related issues.
One of the more useful of these methods is called the bitewing x-ray. The term comes from the shape of the device a patient holds between their teeth with the film attached on the side toward their tongue. We direct the x-ray beam to the outside of the patient's cheek, where it passes through the teeth to expose on the film. Its particular design provides clearer images since the patient's bite helps keep the film still and distortion-free, making it easier to view signs of early tooth decay.
Bitewing x-rays usually consist of four films, two on either side of the mouth, necessary to capture all of the teeth (children with smaller jaws, however, often only require one film per side). How frequently they're conducted depends on a number of factors, including the patient's age: children or young adolescents are usually filmed more frequently than adults, usually every six to twelve months. Frequency also depends on a patient's particular decay risk — the higher the risk the more frequent the x-ray.
Regardless of how often they're performed, a similar application principle applies with bitewing x-rays as with any other radiological method: As Low As Reasonably Achievable (ALARA). With the ALARA principle in other words, we're looking for that sweet spot where we're able to detect the earliest stages of dental disease with the least amount of radiation exposure.
Bitewings fit this principle well: a patient receives only a fraction of the radiation exposure from a four-film bitewing as they do from a daily dose of environmental radiation. Factor in new digital technology that reduces exposure rates and bitewings pose virtually no health risk to patients, especially if conducted in a prudent manner.
The benefits are well worth it. Thanks to bitewing x-rays we may be able to diagnose decay early and stop it before it causes you or your family member extensive tooth damage.
The CAT scan is a relatively recent technique in dentistry, used to get an image of what’s happening deep within your jaws. You may be wondering what a CAT scan tells us that a conventional x-ray picture does not, and whether it is worth the extra expense to get one. And how does a CAT scan compare with a conventional x-ray in terms of radiation exposure?
CAT stands for “computer assisted tomography.” Often it’s just called a CT scan, for “computerized tomography.” The word “tomography” comes from roots meaning “slice” and “write.” Tomographic techniques take repeated two dimensional pictures, similar to repeatedly slicing through an object, and then assembles them with a computer to produce a three dimensional (3-D) image.
The latest type of CT scan used in dentistry is called CBCT, or Cone Beam Computed Tomography. The Cone Beam refers to a spiral beam of x-rays, which is used to create a series of two dimensional images from which a computer creates a 3-D image. Such an image is of great value in assessing problems and planning treatment.
Here are just a few examples of how a CBCT scan can be used. Orthodontists can see skeletal structures and developing teeth that are still inside the jawbone while planning strategies for directing the teeth in order to arrive at a better bite. Oral surgeons can find impacted or missing teeth, see their locations, and view their proximity to nerves and sinuses, assisting them in planning surgeries. These scans are particularly useful for root canal specialists because they show root canals that are less than a millimeter wide and even reveal accessory canals that may not be visible on conventional x-rays. In cases of sleep disorders such as sleep apnea, a CBCT during sleep can be used to view a person’s airway and how it may be blocked by the tongue and other soft tissues in a person’s throat during sleep.
Compared to background radiation, the amount of radiation delivered in dental x-rays is minimal. A CBCT delivers a dose of radiation that is less than a typical full mouth x-ray series but more than a typical two dimensional panoramic radiograph. Generally CBCT scanners deliver lower doses than medical CT scanners.
With one low-dose CBCT scan, we can get an accurate idea of the internal structure of your bones and teeth and how they are situated in relation to each other. Prior to the availability of such images, many of these relationships had to be discovered in the course of a surgery or other treatment. Thus such a scan can aid greatly in the quality of treatment you will receive.
One of the most widely used forms of dental imaging is the bitewing x-ray. So called because of the shape of the device that holds the exposable film a patient clenches between their back teeth, the bitewing x-ray is an effective means for detecting the earliest stages of tooth decay.
These early signs are small lesions on a tooth surface caused by mineral loss in the enamel. While we can identify them on front teeth through visual examination or bright lighting, they’re nearly impossible to see on the biting surfaces of back teeth. The bitewing x-ray solves this problem.
During the procedure, a narrow beam of x-rays is directed at the back teeth area. Since X-rays can transmit through solid matter, they pass through the teeth and gums to expose the film attached to the bitewing assembly.
X-rays pass through matter at different rates depending on the density of the tissue — a slower rate for harder tissues like teeth and bone and a faster rate for soft tissues like the gums. As a result, x-rays through teeth expose less of the film and appear as a lighter image than the gums. This difference is so precise even a tooth’s softer dentin appears slighter darker than its harder outer enamel.
This precision helps us identify decay lesions. Because the lesions on the enamel are less dense than the normal enamel, they’ll appear as dark spots. By detecting them at this stage we have a better chance for reversing the effects of decay or at least minimizing damage that’s already occurred.
Because x-rays emit radiation, there’s a natural concern about over-exposure and we go to great lengths to reduce it. Children may undergo a bitewing x-ray twice a year for developing teeth, while adults with healthy teeth are typically x-rayed just once a year. Advances in digital film and other technology have also helped lower the exposure rate.
Today’s standard 4-film bitewing x-ray produces about four days worth of what we receive on average from normal background radiation, so the health risk is quite negligible. The benefit, on the other hand, is much greater — the early detection of tooth decay could ultimately save a tooth.
For decades, dental x-rays have helped us accurately diagnose and treat a wide array of dental diseases and conditions. But even with recent advances in digital imaging, the traditional x-ray does have one drawback: its two-dimensional view doesn’t always provide the “big picture” that a three-dimensional viewpoint can provide.
But a new type of x-ray technology can do just that: known as cone beam computed tomography (CBCT), these machines record hundreds of digital images as a cone-shaped beam of x-ray energy is projected through a device that rotates around a person’s head. A computer then assembles the images into a single three-dimensional image that can be manipulated on screen to view from various angles. Not only does this provide greater context and detail, it does so with no more radiation exposure than a standard 20-film digital full-mouth x-ray series.
While CBCT hasn’t replaced the traditional x-ray, it’s making its mark in a number of specialized areas of dentistry. The following are just a few of the ways CBCT is improving both accuracy and treatment outcomes.
Orthodontics. CBCT can provide a much more detailed view of the entire jaw; this can help us determine the best locations for realigning teeth safely and effectively.
Dental Implants. With a CBCT scan we can precisely locate nerve canals, sinuses and adjacent teeth before implant surgery to locate the best position for the implant.
TMD Treatment. To help develop the best treatment approach for alleviating the pain and dysfunction of temporo-mandibular joint disease (TMD), a CBCT scan can provide us detailed information on how the disease is affecting a patient’s joints, teeth, sinuses and airway.
Impactions. An impacted tooth can exert damaging pressure against the roots of neighboring teeth. A CBCT scan allows us to observe the impacted tooth from various vantage points to determine the best treatment approach for neighboring teeth, nerve canals and sinuses.
If you would like more information on CBCT technology, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “Getting the Full Picture With Cone Beam Dental Scans.”