A Brief Overview on Digital Radiography Systems
THE NEXT DDS
Think for a moment of the contribution radiography will make to
your practice. Consider the value of radiographs in diagnosis, treatment, and
patient education. Digital radiography provides these benefits and can be
faster, safer, and easier than conventional radiographs. Digital radiography is
the answer for a growing number of practitioners—their staffs and patients
too—who have upgraded to digital solutions, and the potential exists for you,
as future dentists, to harness its benefits as well.
Digital radiography delivers diagnostic, archiving, and cost
control capabilities unobtainable using conventional radiographic film. The
central question is no longer “Should I?”, but “How do I?”. This article will
help you visualize the benefits of digital radiography, understand the
characteristics of the two major types of systems, and gain basic knowledge
that will assist you in selecting a system for your future practice.
Advantages of Digital
Radiography for the Dentist
Digital radiography is a powerful visual tool. All digital systems
present radiographic images on a monitor, where they are larger, sharper, and
easier for you and your patient to see. Image characteristics such as
brightness, contrast, sharpness, and magnification are all adjustable to suit
your preferences, creating a powerful presentation and diagnostic aid. Well-educated
patients often more readily accept treatment, and are better equipped to maintain
their oral health. Digital radiography allows the patient, guided by the dentist,
to visualize options and outcomes. Imagine simplified diagnosis as conducted
from a clear, monitor-size image rather than a square–inch- sized piece of film.
Digital radiography also improves the productivity of the practice.
Every step in the imaging process requires less time and produces results far
superior to film. Every cleaning and maintenance task (and the cost) associated
with film processing is eliminated. This productivity benefit is often dismissed.
Remember: the most successful practice and the least successful practice both start every day equally; each is
given the same amount of time. Digital radiography delivers real, measurable
productivity gains. Attract talented members to your team using the
nonfinancial incentive of digital radiography. People inherently gravitate to
modern equipment and want to treat patients using contemporary modalities that
are effective and productive. The speed, ease of use, and freedom from
maintenance enable all members of the dental team to focus more on patient
care. Total imaging expenses can also be better managed, because the
significant costs of film processing and maintenance labor are eliminated.
Two Types of Digital
There are two distinct technologies. The first are termed “direct”,
meaning that their receptors send data directly to a computer via wires or
wireless transmission. The second type of digital system is “indirect”. With
these, the receptor is inserted into a reader or scanning device that sends
data to the computer. Indirect systems create images using phosphor storage plates
(PSP). Both sensor and PSP systems are used in thousands of dental practices,
though there are differences in their design, operation, and performance. The
key to your success with digital radiography is to choose the products that will
work best for you, under your actual conditions.
There are two types of sensor architecture--CCD (Charge-Coupled
Device) and CMOS (Complementary Metal Oxide Semiconductor). There is
considerable ongoing debate regarding the respective merits of these competing
technologies. Many experts believe that for an exacting imaging application
such as medical and dental radiography, the CCD sensor is the best choice
because it produces the most detail-rich, lowest-noise image. However, CCD
sensors sometimes have a higher initial investment than CMOS products. The data
captured by the sensor is transmitted to the computer via wired USB, Ethernet, wireless
RF, or Bluetooth. The latter is the newest technology used for transmitting and
already widely used in mobile communication devices.
Sensors offer speed to the user. From exposure to image
presentation on the monitor takes only a few seconds. Sensors are commonly used
during endodontic procedures or for trauma cases, where speed is imperative.
Sensor images are created chairside. There is no need to leave the operatory
Sensors are available sizes 0, 1, and 2. If you require other film
sizes such as 3 or 4, you may face a quandary, as these sizes are not
available. The average cost of a size 2 sensor today is $7,000.00. Additionally,
they often require a longer learning period. Because sensors are rigid and
thicker than conventional film, new positioning techniques must be learned.
Since every patient is unique, not everyone will tolerate the thickness and
rigidity of a sensor, particularly children and those with small mouths.
Clinicians who own a panoramic or cephalometric x-ray unit face a dilemma when
they wish to convert to digital radiography using sensors. These users will need
to either buy a direct digital extraoral x-ray, which can cost in excess of
$35,000 or have a digital conversion added to their present extraoral machine (if
that option exists).
Phosphor Storage Plate Systems
In an “indirect” phosphor storage plate system, the radiographic
image is captured using a wireless PSP. Since they are not directly connected
to the computer, a device is required to read or extract the data from the PSP
and send image data to a computer. The PSPs have several important
characteristics. They are available in all film-equivalent sizes: 0, 1, 2, 3
and 4 plus panoramic and cephalometric. A PSP is flexible and thinner than a
piece of dental film, so it can be easily positioned in the mouth using the
same techniques and holders that are currently used for film. PSPs have a long
service life, typically in the range of 1,000 exposures. When compared to
sensors, plates are very affordable; a typical size 2 PSP costs about $25.
There are several indirect or PSP systems available. Some process
only intraoral sizes; others process both intra- and extraoral sizes. Some
systems will accept only a single PSP at a time; others accept multiple plates
and sizes at the same time. Finally, some products require that the PSP be
placed in a holder or carousel before insertion into the scanner; others are
direct-feed, where the PSP is placed into the scanner with no additional
If your practice has a film-based panoramic or cephalometric x-ray,
it is easy to upgrade to digital with the appropriate PSP system. Simply
replace the film with the correctly sized PSP and remove the intensifying
screen from the film cassette (if one is present). Expose as with film and
place the PSP in the scanner to be read. Your extraoral x-ray is now converted
to digital; there is no need to buy new equipment.
Selecting the Proper
The move to digital radiography can be fun, exciting, and
rewarding. The insights and counsel of your mentor—or even your dealer—can be
invaluable as you contemplate selection of the appropriate system. You will
want support when making this important decision for your practice. Plan for
the change, consult with manufacturers, and choose the system and software that
meet your needs best. Every day, digital radiography systems help more dentists
achieve superior imaging results. Explore the possibilities and enjoy the
Table 1: Questions to Answer When Evaluating a Digital Radiography System for Your Practice
- Is your computer system ready for digital imaging?
- Is the manufacturer you are choosing one you can
- Will you image intraorally, extraorally, or both?
- Can the system be used with your present extraoral radiography
- Will the system enable you to image using all
- Will the system work in normal room lighting?
- Does the system offer multiple resolution settings?
- Is the product easy to use?
- Are images created quickly?
- Will the product work with many brands of software?
- Does the system fit the way you work?