Picture This!

Calabro, Lisa, Ann Marie Farrugia, Kate Kennedy, and Sarah Kuczynski

To compare and contrast the various types of radiography used in the dental office. Digital radiography has been introduced in many offices, replacing traditional film based radiography. By using computer technology, digital imaging has advanced the dental profession by facilitating the acquisition, storage and transfer of radiographic images using sensors in a totally different format than film based radiography.

The two different mechanisms in digital image formation are the solid state sensors systems, which use CCD (chargecoupled device) or CMOS (complementary metal oxide semiconductor) sensors, and the PSP (photostimulable phosphor, or storage phosphor) system. The CCD- or CMOS-based solid state imaging system captures the image by using a chip as a sensor for the radiation. A cable connects the sensor to the computer, although a wireless CMOS sensor is also available. After x-ray exposure, the altered electron pattern on the sensor is sent into the computer through the cable and the image is portrayed within seconds on a computer screen. The PSP sensor is not connected to the computer by a cable. It is positioned intraorally and exposed to form the latent image. The information contained on the sensor is made visible on the monitor after the plate is scanned by a laser.

Solid state digital radiography has a 90% dose reduction compared to D-film speed, and approximately 50% dose reduction compared to F-speed film. Dose reduction with PSP sensors is not as great. Image manipulation, such as magnification and contrast enhancement can be performed. Digital radiography increases speed and eliminates chemical processing. The cost to the dental office for digital imaging is almost double the cost of conventional radiography to purchase. Therefore, the office staff must be committed to the change and must be trained to use the systems. The training will help eliminate cross contamination which is an issue since the sensors are reused.

There are advantages and disadvantages of using the different types of radiography. There are several types and styles that can be chosen to suit each individual office. It must not be forgotten that the diagnostic qualities of digital radiography and film based radiography have little differences but convenience and manipulation change drastically.