Lorne Lavine, DMD
Technology has been the driving force in many of the advances we have seen in dentistry. This is as true in other fields as it has been in dentistry. In the early 1990s, intraoral cameras were all the rage. In the late '90s, it was digital cameras. And, at present, no other topic seems to generate greater interest than digital radiography. While entire books could be written on the subject, the goal for this article is to briefly review the pros and cons of the three different systems of digitized radiographs.
Scanners
Although it certainly is not a digital-radiography system in the purest sense of the term, many offices use scanners to digitize their existing X-rays. Even offices that have elected to purchase a true digital system must deal with the issue of having thousands and thousands of film X-rays that ideally should be part of the patient's digital record. Scanners also are an excellent option for the office that desires some of the advantages of digital, but finds the costs to be prohibitive.
In this scenario, films are developed in their usual fashion and are then scanned into software. Many scanners come with their own software, although I would recommend using dental image-management software. The key feature when choosing a scanner is the Transparency Unit Adapter (TPU), which is a light source that is in the lid of the scanner rather than in the base. Many midpriced scanners only have a 4-inch by 5-inch TPU. While that's fine for bitewings or a few PAs, it would not be adequate for a panograph or full-mouth series in their mounts. In these cases, a full-sized TPU is needed, and only a few scanners meet this requirement. The Epson 1680 Professional is the industry-standard, with the Microtek 9800 being another good choice.
Phosphor plates
While some people consider phosphor plates to be positioned between scanners and direct sensors, these systems are actually very highly developed and produce diagnostic-quality images. The plates are "scanned" in a special machine, which is basically a laser that reads the phosphor plates. The system must be attached to a computer which is running compatible software. The main advantage of phosphor plates is their similarity to film. They are as thin — and often thinner — than film packets. The staff can take images with the same RINN kits and methods that they use for film. They then take the plates to a centralized "processor" to "develop" them, and mount the images afterwards. The one difference is that the mounting occurs in software templates, not in cardboard or plastic mounts. Also, unlike direct sensors, the plates are relatively inexpensive, which is wise since they typically must be replaced after 500-700 uses.
On the downside, the plates are easy to scratch and while they theoretically can last through 500 uses, damage will normally require that they be replaced more frequently. Phosphor plates have less resolution, in line pairs/mm than sensors. While this would not make a difference when viewing images on a typical 15- or 17-inch monitor, it can make a difference if you are magnifying the image to a great degree or printing out images that are larger than 8 x 10 inches. Also, because of the steps needed to obtain an image, the time needed to take phosphor plate images is very close to the time needed for film.
Direct sensors
Direct sensors are silicon-based receptors, often encased in protective coating, that mimic the size and shape of PA film. These sensors, which are either CMOS or CCD, are connected to a thin cable which runs from the sensor to some device that connects it to the computer. The sensors range in thickness from about three to eight millimeters. The main advantages of sensors are speed and image quality. Images taken with a sensor appear almost immediately on the screen, making them the ideal choice for offices which do a lot of endo or implant procedures. They are comfortable, sturdy, and have excellent resolution. Many can produce a highly diagnostic image when used with the proper software.
On the downside, they are thicker than film and have cables running off the sensors, which some patients don't tolerate well. Also, they are not inexpensive, as a No. 2 sensor can range in price from $5,000 to $14,000.
Lorne Lavine, DMD, practiced periodontics and implant dentistry for more than 10 years. He is an A+ Certified Computer Repair Technician, as well as Network+ Certified. He is the president of Dental Technology Consultants, a company that assists dentists in all phases of technology integration in the dental practice. He can be contacted by email at [email protected] or by phone at (866) 204-3398. Visit his Web site at www.thedigitaldentist.com.
