Two main types of digital systems are available today:
DR systems include a “sensor” and software, and are used with an existing dental X-ray machine and computer. The sensor is connected via USB cable to a computer, and is placed in the patient’s mouth and positioned like ordinary dental film. (show image of the X-Ray generator and a film in a dog’s mouth like in positioning guide) The largest sensor size currently available approximates the size of #2 dental film. Images are viewed in seconds, and may be digitally manipulated to heighten detail and minimize re-takes. The sensors are the most expensive part of the system, and although they are quite durable, care must be taken to prevent damage.
CR systems involve the use of “phosphor screens”, which look similar to ordinary dental film. After exposure, the screens are fed into a scanner, which gives you an image in around one minute. The phosphor screens are exposed to bright light to erase the prior image, and can be re-used hundreds of times. This type of system is more expensive, but does have the advantage of being able to produce larger #4 films.
The chart below compares various features of DR and CR systems. DR systems are currently more popular due to the speed with which you can obtain images.