Sensor-based radiography systems

The push towards digital radiography is a driving force at this time. While surveys show that less than 15 percent of dental offices currently use digital systems...

Lorne Lavine, DMD

The push towards digital radiography is a driving force at this time. While surveys show that less than 15 percent of dental offices currently use digital systems, these same surveys indicate that many dentists are considering adding digital radiography to their practices in the next 12 months. With this in mind, we will begin to evaluate the systems on the market.

The majority of dentists who currently own digital radiography systems have sensor-based systems. Since I don't expect this trend to change anytime soon, I would like to review the criteria that dentists should consider when selecting the right system for their offices. This is meant to serve as a simple primer. You should consider working with a consultant since this decision can have far-reaching implications on your practice.


Resolution is the number that most companies advertise when marketing their systems. The resolution refers to line pairs per millimeter (lp/mm). Many sensor-based systems will be able to produce an image with at least 15 lp/mm; some are in the 25 lp/mm range. The questions becomes: Will a sensor with more resolution produce a better image than one with less resolution? Not necessarily! Image quality is affected by many factors, such as the monitor you are using and the software that is interpreting the image. The human eye cannot reliably distinguish images that have more than 12 lp/mm. The better resolution will only come into play when magnifying the image to a large size either on the screen or when printing. If you enlarge an image further and further, the image with less resolution will begin to degrade and show pixilation earlier than the higher-resolution image. When printing an image, the resolution becomes important when printing images larger than 8" x 10." For most offices, the lp/mm issue is not as important as the sensor companies might like to have us believe.


One of the goals of the sensor companies is to allow dentists an easy transition from a film-based practice to a digital practice. Most accomplish this by creating sensors that simulate the size of film. The vast majority of companies produce both a No. 1- and a No. 2-sized sensor. A few also make a Size 0 sensor, although few offices use these. On the other side of the coin, a couple of vendors believe that there is no need for separate sensors and they produce a "one size fits all" sensor. While this type of system may reduce costs, you will find there are situations where a small sensor is needed. Some examples would be for pedodontic patients, patients with tori, or patients with constricted mandibles.


Most vendors are moving toward a thinner sensor. While a few are still in the 5 mm range, the industry standard is currently around 3.2 mm. However, the thickness of the sensor usually is not crucial in determining comfort. Instead, it is the actual design of the sensor casing, corners, and edges that play a more important role. Some are square, some are rounded, and some are octagonal. Try the different sensors for comfort if this is an important part of your decision. Many companies make holders for sensors that also will have a large affect on the patient and operator experience. Many use a RINN-style holder, but a number of variations and other systems are used.


For many dentists, this is probably the most important factor. While the costs of the various systems have continued to decline, we're still talking about a significant investment. This does not even consider the costs of computers, monitors, networks, and software. The average price of a No. 2 sensor system is around $9,000. A few can be found for $5,000, a number of systems are priced in the $7,000 to 9,000 range, and a couple are priced at $12,000 to $14,000. You should also be aware that most sensors come with only minimal warranties, and extending those warranties will cost $500 to $2,000 per year per sensor. This should be factored into your final cost figures.

There is no perfect digital-radiography system. Dentists must decide which factors are most important to them and base their decision on those factors. There is no right or wrong — only what is best for you!

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 or by phone at (866) 204-3398. Visit his Web site at

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