Posts for tag: x-rays
Radiographic (x-ray) images are an indispensible diagnostic tool in dentistry. One of the most routine and useful types of x-rays dentists take is the so-called bitewing. Here are some things you may want to know about this common diagnostic procedure.
What are bitewing x-rays?
Bitewings reveal the presence and extent of decay in the back teeth, specifically in areas where adjacent teeth touch each other. Unlike other areas of the teeth, these contacting surfaces between adjacent teeth can’t be examined visually. Bitewings can also show areas of bone loss around teeth — a sign of periodontal disease; however, they are not taken for that purpose because bitewings will not show the complete root surface that is surrounded by bone.
Why are they called that?
The name “bitewing” refers to how the film — or sensor, in the case of a digital x-ray — is positioned in the mouth: The patient bites down on a little tab or wing that holds the apparatus in place.
How often do I need them?
This is determined on a case-by-case basis, with the goal of not exposing you to any more radiation than necessary — even the minimal amount found in a series of bitewing x-rays. Your individual susceptibility to caries (tooth decay) and personal dental history will play a major role in determining how frequently you need radiographic examination — and, for that matter, how often you need to come in for routine cleanings and exams.
Are they safe?
The safety of bitewing x-rays is best illustrated with a comparison to the regular daily radiation exposure we get every day from environmental sources, which is about 0.01 millisieverts — the unit of measure we use for radiation. A series of 4 bitewing x-rays exposes you to 0.004 millisieverts of radiation — less than half of the daily exposure. Undetected tooth decay, which can spread quickly through the softer inner layers of teeth, is considered much more dangerous!
If a bitewing x-ray shows that there is tooth decay, what happens next?
If the cavity is very small, we may be able to treat it during the same appointment. If not, we will make a separate appointment to make sure it is taken care of promptly. The sooner tooth decay is treated, the better!
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.”
There’s no question that x-ray imaging has transformed how we diagnose and treat dental problems. But traditional x-rays have at least one limitation — they are two-dimensional portraits that can only provide a portion of the information available. If you could view the interior of teeth or other mouth structures in three dimensions, you would have access to more detail about their conditions.
Computerized axial tomography (CAT) scanning has brought that third dimensional view to physicians generally and, in more recent years, to dentists. The latest development in this technology is known as Cone Beam Computed Tomography (CBCT). A CBCT emits a spiral of x-rays that form a cone-shaped beam that is caught on detectors. Using digital geometry, the CBCT then generates a three-dimensional image by precisely “layering” this large series of two-dimensional images caught by the detectors on top of each other.
CBCT is already making a significant impact in dentistry and its related specialties. Dentists now can visualize with amazingly precise detail the three-dimensional anatomy of the teeth, jaws, facial bone and other structures in the head and neck area. Orthodontists can examine the growth stages of a patient’s teeth eruption to better prepare treatment strategies. Oral surgeons can determine the precise location of impacted teeth and their exact proximity to nerves and sinuses. And, periodontists who specialize in gum disease and treatment can better determine the level of bone loss and gum attachment for more accurate diagnoses and effective treatment.
While a CBCT delivers a higher dose of x-rays than a traditional panoramic radiograph, it actually delivers a lower dosage than a digital standard 18 film full mouth series or than conventional medical CT scanners. The field of view also determines the level of x-ray exposure — the smaller the field of view (and more concentrated the x-rays) the higher the dosage and the better detail of anatomy.
The good news, though, is that a low dosage CBCT scan can still provide a level of detail that can provide dentists with a very accurate view of anatomical features, including bone density and mass, in three dimensions. That capability can vastly elevate the accuracy of diagnoses and lay the groundwork for effective dental treatment.
If you would like more information on the uses of CBCT scanning to help you maintain dental health, 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 “CAT Scans in Dentistry.”
Your dental care would be much more limited without our ability to see “below the surface” with x-ray imaging. But since x-rays passing through the body are a form of radiation, could your exposure from them be hazardous to your health?
It depends on exposure dosages and, of course, the amount you have been exposed to over your lifetime. But, decades of research have demonstrated that exposure to dental x-rays during your regular office visits are only a fraction of the radiation you normally encounter from the natural environment every year.
X-rays have the ability to pass through body tissues, but at different rates for soft tissue like skin and muscle and hard tissue like bone. This effect creates shadows on exposed film; the differentiation is in such detail that a trained technician can interpret not only internal structures, but defects such as fractured bone or, in the case of dentistry, signs of tooth decay and bone loss from gum disease.
But like other energy sources in our environment, x-rays do emit radiation that in high doses can be dangerous to living tissue. The amount of exposure is measured in millisieverts (mSv), a unit that allows for comparison of doses from different sources of radiation. Scientists have calculated that we’re normally exposed to between 2 and 4.5 mSv every year.
By contrast, a single digital periapical image taken of a tooth is equal to 1 microsievert (μSv), or one thousandth of an mSv; a full mouth series (between 18 and 20 images) creates an exposure of 85 μSv, or 85/1000 of one mSv. In addition, advances in technology have further reduced the radiation exposure from x-ray imaging. For example, digital imaging has reduced exposure during full mouth x-rays from seven to ten days of equal exposure from normal background radiation to half a day, and with no loss in image quality.
In effect, dental x-rays pose little to no risk for patients. Still, understanding that x-ray imaging does expose patients to radiation, dentists follow certain protocols and safety precautions. For example, dentists will place a lead apron around their patients’ chest area during an x-ray exposure.
As your dentist, we’re happy to address any concerns you may have about x-ray radiation exposure. But rest assured, the x-ray devices used in your dental care, so necessary in the fight against tooth decay and other diseases, are safe and reliable.
If you would like more information on the use of x-ray technology and safety, 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 Frequency and Safety.”