November 28, 2015
Radiographs, also known as x-rays, play an integral part in the assessment and diagnosis of periodontal infection (gum disease) and dental caries (cavities). There are two common types of dental x-rays: x-ray film placed inside the mouth (intraoral) and x-ray film placed outside the mouth (extraoral). The most common being intraoral x-rays, of which there are several types. Each shows a certain aspect of teeth. With Bitewing x-rays the dentist captures details of both the upper and lower teeth, from the crown all the way to the supporting bone, in one area of the mouth. These radiographs can also show developing teeth in children and adolescents. For many dentists this is the method of choice to determine the presence and extent of decay.
Diagnosing Dental Decay
Generally a dentist can diagnose decay by visual examination. However, this is only effective when demineralization creates the hole in the enamel. The early lesions of decay only weaken the enamel, and are often impossible to detect with the naked eye. With bitewing dental x-rays the dentist can see the earliest signs of decay, even on the contacting surfaces of back teeth, making it easier to reverse or treat dental caries.
What are X-rays?
Technically the term x-rays refers to waves of radiation beyond the visible spectrum. These waves pass through soft tissues, but do not pass readily through harder tissue. So, just as photographic film captures light to create pictures, radiographic film records images from the x-rays in black, white, and gray. The more dense portions of bone show up white, dissolved or thinner surfaces like dentin appear gray, and softer tissues show up as black. This is why the dentist can see cavities, because they appear darker than the normal tooth structure.
What are Bitewing X-rays?
The name for bitewing x-rays comes from the shape of the x-ray film. It looks like the shape of a “T”. There are small tabs the patient bites on to hold the film strip in place. The film extends to both upper and lower teeth and dentists use it most often to get x-rays of back teeth most susceptible to decay. The bitewing radiographs are easy to use. They are also the most accurate with distortion free images. Usually a full set of x-rays includes four captures, two on each side. During your first appointment or a full evaluation, the dentist will take a full set of periapical x-rays (full panoramic or digital). Then the dentist uses bitewing x-rays to track changes during interval checkups, saving patients the time and expense of a complete set of x-rays.
Process for Dental X-rays With Bitewing
The dentist or assistant will place the film on the inside of your teeth, have you bite down to hold it in place, and then they will capture the x-ray. The dentist can also place the film strip in a vertical direction to also show bone density and volume, to check for signs of periodontal decay or measure for dental implants. Once the film is in place the dentist uses the x-ray machine to expose the film. The energy beam is collimated, minimizing the area and length of exposure.
Should Patients Have Concerns About Radiation Exposure?
When it comes to radiographs in the dental office, professionals always put safety first. Bitewing x-rays carry little risk for patients, in both adults and children. The dentist knows what precautions to take and carefully safeguards patients with lead aprons. Also, the digital sensor technology and high-speed film works to significantly reduce radiation exposure. That said, young children and pregnant women should take extra caution when getting x-rays and postpone them unless absolutely necessary.
How Often Should a Patient Get Bitewing X-rays?
There is no one size fits all solution. Instead, the dentist uses an ALARA principle (as low as reasonably achievable) as a general guideline. Dental care providers only take as many radiographs as diagnostically necessary. It is up to the patient and the dentist to work out a set schedule after evaluating the benefits, risks, and alternatives. The dentist considers the patients age, risk of decay and periodontal disease, and other clinical factors. That said, it is not uncommon to have bitewing x-rays taken as often as every six months to a year. This is the best timetable to stay ahead of decay, and catch problems in the earliest stages. The alternative is a rapid progression of decay and infection, extensive repair, and perhaps even tooth loss.