by Gordon J. Christensen, DDS, MSD, PhD
In this monthly feature, Dr. Gordon Christensen addresses the most frequently asked questions from Dental Economics® readers. If you would like to submit a question to Dr. Christensen, please send an e-mail to [email protected].
For more on this topic, go to www.dentaleconomics.com and search using the following key words: radiographs, diagnostic standards, radiation, digital vs. analog radiographs, Dr. Gordon J. Christensen.
Q What is considered to be the standard for diagnostic oral radiographs in a typical general practice? I have heard and observed everything from only a panoramic radiograph to the conventional 14 to 18 exposure full-mouth series. I want to offer my patients good service for my exams, but I do not want to overdo the radiation exposure. What do you suggest?
A Your question is more complex than it appears. There are numerous types of radiographs available today, and they relate to the specific needs of patients. I will discuss your question from various aspects in an attempt to make it more practical and understandable.
Digital vs. analog radiographs
The dental profession in North America has been relatively slow to implement digital radiography compared to other developed countries. The advantages of digital radiography are well known, and there are significant reasons to accept this major change as an important improvement in diagnosis and treatment- planning. The advantages are:
- Immediate observation of images
- Magnifying images
- Measuring distances between various features on radiographs
- Enhancing images with texture or color
- toring images for immediate retrieval
- Great for patient education
- Increasing or decreasing contrast is easy
- Elimination of the developer
- Easy to e-mail to patients and other practitioners
- Lower radiation than analog
However, there are a few disadvantages including the following:
- Cost is significant
- Conversion from conventional to digital requires time and effort
- Learning to use the concept takes time
- Breakage or loss of sensors
- Thickness of sensors
- Rigidity of sensors
- Current lack of universal use of digital
In the event that you have not integrated digital radiography into your practice, I suggest you do so as soon as you can afford to purchase the devices. In a few years, analog radiography will vanish, as has film for photographs.
Most dentists who have digital radiography use CCD/MOS systems that allow for immediate observation of the images; however, some are using phosphor plates that are less expensive and have thinner sensors. Phosphor plates do not provide an immediate image, and you must place the plate into a processor to allow an image to appear on your monitor.
Type of practice and usual radiographic needs
The type of patients usually treated in a specific practice relates directly to the radiographs considered to be most appropriate for diagnosis and treatment-planning. I will use actual patient radiographs to demonstrate the relative acceptability of the various types of current digital radiographs.
Periapical radiographs: Most dentists use periapical radiographs daily for a variety of diagnostic and documentary reasons. I suggest having the availability of a state-of-the-art periapical digital radiographic device. Some of the most popular brands are: Schick, DEXIS®, Kodak, Sirona, GE, Gendex, and many others.
Full-mouth periapical radiographic series (Fig. 1): When many teeth are in the mouth, most dentists prefer making periapical radiographs of all of the teeth. A typical full-mouth series includes the following separate images: molars (4), premolars (4), canines (4), anterior teeth (2), for a total of 14 separate images. These 14 images are usually augmented with four bitewing radiographs. If many teeth are missing, only a few periapical radiographs are usually indicated. If only a few teeth are remaining in the mouth, a panoramic radiograph may be adequate. The ability of either analog (D-speed film) or digital radiographs to show initial dental caries has been studied and compared. Neither type of radiograph shows initial caries well. Additionally, panoramic radiographs do not show initial caries. Some dentists have eliminated the 14-to-18 image, full-mouth series and use only panoramic radiographs. Patient education using only periapical radiographs is difficult, since many teeth are duplicated in the various views, and this is confusing to patients.