Dental X-Rays
X-rays are such a routine part of regular dental care today that it’s hard to imagine what a truly revolutionary impact they have made in dentistry. Discovered by German scientist Wilhelm Röntgen in 1895, x-rays were first utilized by doctors for viewing internal bodily structures in the early 20th Century. By mid-century, dentists were routinely using the technology to diagnose tooth decay and periodontal (gum) disease, as well as other diseases that are not visible through a clinical examination. The ability to see what’s inside the tooth and catch decay or gum disease at early stages has vastly improved the success of dental treatment.
While advances in digital imaging and equipment technology have increased the capabilities (and safety) of this versatile diagnostic tool, the basic principles of x-ray imaging remain much the same for today’s dentist as for their counterparts decades ago.
How X-Rays Work
X-rays are a form of electromagnetic radiation, similar to light but with a shorter wavelength. As such, they have the ability to penetrate many types of matter, including bodily tissues. The rate of penetration, however, depends on the density of the tissue: The rays pass more easily through soft tissues, like skin or gums, than they do hard tissue, such as teeth and bones.
To produce an image, x-rays are directed at the area we wish to observe. After passing through the body, they are captured on the other side by a plate of photographic film or a digital receiver (a radiograph). Because of the differences in absorbtion, the developed or digitized film produces images of internal structures in sharp detail. With this level of precision, a dentist can detect minute areas of tooth decay in their early stages, which appear as dark spots on the lighter-imaged teeth.
Safety and X-Ray Radiation Exposure
Although x-rays have been used in dentistry for decades, it’s still worth bearing in mind that they are a form of radiation—and all forms of radiation (even sunlight) can have harmful effects on the human body if the exposure is too frequent or the dosage too high. To put the issue in context, however, it should be noted that everyone is constantly exposed to background radiation from the environment. Using a standard measure of radiation exposure called the millisievert, many studies have concluded the average person is exposed to between 2.0 and 4.5 millisieverts of radiation annually from the environment.
By comparison, the radiation exposure from a single x-ray of a tooth root (a periapical film radiograph) is one-tenth the daily exposure from environmental sources, and that of four bitewing radiographs is about 40%. Even the highest exposure, a full mouth series (18 to 20 radiographs) on standard film is only equal to a full day of environmental exposure.
Since an individual is exposed to low-dose dental x-rays infrequently, the proven diagnostic value of x-rays in dental care generally outweighs any potential health risks they may have. To further enhance patient safety, dentists also follow strict protocols (different for children and adults) that limit x-ray exposure to only what is absolutely necessary, or “as low as reasonably achievable” (ALARA).
Innovations in X-Ray Technology
In recent years, x-ray diagnostics have benefitted from a number of technological advances. Digital imaging has become more prevalent, thanks to increases in computer processing speed and power. This allows medical professionals to create highly detailed images with less radiation exposure than is needed for conventional film.
Another recent innovation, also based on advances in computers and digital imaging, is cone beam computed tomography (CBCT). This technology uses x-rays to capture a series of hundreds of images from various angles around a patient’s head. When the digital images are processed and assembled by a computer, they provide a highly detailed, three-dimensional representation of the teeth, mouth and jaw structures. This 3-D image can be manipulated on a computer screen, allowing specialists to optimize dental procedures by visualizing them in full detail from different points of view.
Although it is not a replacement for the standard two-dimensional x-ray, CBCTs are proving highly useful in many areas of dentistry, including orthodontics, endodontics, periodontics and oral surgery. This technology is especially useful with dental implants, where improved diagnosis and planning results in more successful outcomes.
A Crucial Part of Effective Dental Care
Dental x-rays play a critical role in the fight against tooth decay and other dental diseases. They are also an important planning tool that can improve the outcomes of specialized dental procedures. As the technology continues to advance, it’s a safe assumption that x-ray diagnostic imaging will become even more efficient and useful.