Oral Health Group

Digital Sensors

August 9, 2012
by lorne

Over the past few columns of  this blog, we have examined many of the factors that go into upgrading the practice towards a chartless system. While many of these concepts are important in the planning stages, it is apparent that the push towards digital radiography is the driving force at this time. While surveys show that less than 50% of offices currently use digital systems, these same surveys seem to show that many dentists are considering adding digital radiography to the practice in the next 12 months. We looked at phosphor plates systems in the last column, so let’s turn our attention toward hard sensors now.

The majority of dentists who currently own digital radiography have sensor-based systems. Since I don’t expect this trend to change anytime soon, I would like to review the different criteria that dentists should consider when picking a system that is right for their office. This is simply meant to be a primer; dentists should contemplate working with a consultant since this decision can have far-reaching implications on the practice as a whole.

The number that most companies advertise when marketing their systems in 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. The questions becomes: Will a sensor with more resolution produce a better image than one with less resolution? Not necessarily. As we’ve discussed in past issues, image quality will be related to many factors, such as the monitor you are using and software that is interpreting the image. It has actually been shown that the human eye cannot reliably distinguish images that have more than 10 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 become to degrade and show pixilation earlier than the higher resolution image. As far as printing, the resolution will become 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 #1 and #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, offices will find that there are situations where a small sensor is needed. Some examples would be for pedo patients, patients with tori, or constricted mandibles.

Most vendors are moving towards a thinner sensor. While a few are still in the 5-6 mm range, the industry standard is around 4 mm right now. However, the thickness of the sensor is usually not crucial in determining comfort. Instead, it is the actual design of the sensor casing and the corners that play a more important role. Some are square, some rounded, some octagonal. Dentists should try the different sensors for comfort if this is an important part of the decision for them. Many companies make holders for sensors that will also have a large affect on the patient and operator experience. Many use a RINN style holder, but there are certainly a number of variations and other systems in use.

For many dentists, this is probably the most important factor. While the costs of the various systems have continued to decline (in most cases), these are still a significant investment. Not even considering the costs of computers, monitors, networks, and software, the average price of a #2 sensor system is right around $5000-7500 right now. There are a few that can be found for under $5000, a bunch priced in the $7000-9000 range, and a couple above that. Dentists should also be aware that most sensors come with only minimal warranties, and extending those warranties will cost $500-$2000 per year per sensor, so this should be factored into the final cost.

There is no prefect digital radiography system. Each dentist must decide which factors are important and base their decision on that. There is no right or wrong; only what is best for you.

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