Somebody’s Watching Me

July 1, 2010
Can we replace the explorer? How many times does the person doing an exam note a catch and watch?

Paul Feuerstein, DMD

For more on this topic, go to and search using the following key words: minimally invasive procedures, digital radiography, intervention, Dr. Paul Feuerstein.

Can we replace the explorer? How many times does the person doing an exam note a catch and watch?

In the days of amalgam and G.V. Black preparations, this made sense — wait until it is big enough to fill, based on materials and guidelines. Things have changed. There are discussions such as “Do we fill it, watch it, seal it?” “How about PRR, glass ionomer?” Today, with minimally invasive procedures (air abrasion, laser, mini burs), flowable composites, other restorative materials, and even the new MI Paste, we can take care of decay with earlier intervention and save tooth structure.

Digital radiography has helped us discover smaller lesions, and we use filters or a clever piece of software from Kodak called Logicon. Still, this technology does not find incipient lesions that are just breaking the dentin/enamel junction.

KaVo entered the marketplace several years ago with the digital explorer called DIAGNOdent. This is a low wattage diode laser that can be placed directly on the suspicious occlusal area, fluoresces the tooth, and gives a digital feedback reading that lets you know if there is a carious lesion. It uses a scale of 0 to 99 and an accompanying sound — the higher the number, the larger the lesion below the surface. The device has been described as being like radar or sonar.

Each practitioner decides on the number at which a restoration is necessary. Typically, lesions greater than 30 are found to be carious. Clinical judgment must still be used — a 70-year-old patient with a low caries rate and a 35 reading might still be a “watch,” while a 20-year-old with a Mountain Dew addiction might be better served restoring a 25. The score can be recorded and reviewed at a subsequent recall. If the numbers increase, it is time to restore.

Until recently, DIAGNOdent had an exclusive. DENTSPLY has introduced the Midwest Caries ID. It is an LED-based detection system that signals decay occlusally and interproximally. It uses red and green lights plus sound as an indicator but has no numeric reading.

Air Techniques has a detection system called Spectra. Spectra identifies cariogenic bacteria based on the fluorescence principle. LEDs project high-energy blue light onto the tooth surface. Light of this wavelength stimulates bacteria to fluoresce red while healthy enamel fluoresces green.

The teeth images appear on a computer screen (looking like Doppler weather radar) with numeric values that indicate caries activity. These images can be stored and compared to values at subsequent visits if there are questions.

Acteon has introduced SoproLife, a combination all-in-one high-grade intraoral camera and blue fluorescence light. Unlike Spectra, it gives a visual rendering of areas of decay. “Good” dentin glows green while decay shows up as orange and red. There is a diagnostic setting for preop and a working setting that allows you to look instantly at a preparation and see if there is decay remaining. For more, go to

A Canadian company created the Canary Caries detection system. This technology uses a laser, along with slight heat, to find caries on surfaces. This includes around restorations. For more, visit

Finally, a company in Scotland has produced CarieScan. This device uses AC impedance spectroscopy to send a low-level current through teeth at various frequencies. More specifics can be found at

Lantis Laser has taken a different approach with a system that we might see later in 2010. The company uses optical coherence tomography (OCT), which uses a high-intensity light. Information is captured by shining a near-infrared light through a single optical fiber, only .006 mm in diameter, deep into 3 mm of the tooth.

The handpiece is then moved over the surface of the tooth, and it captures reflected light at more than 2,000 points. A computer analyzes these reflections to form a cross-section image that is displayed in real time on the computer monitor. The images look like mini CT slices of the tooth. More information is at

At this year’s Chicago Midwinter meeting, a product prototype called “s-ray” was introduced that uses ultrasonic frequencies to map decay, even if under a cast crown. While this sounds exciting, I would like to see it clinically. For more information, go to

These high-tech devices I have mentioned still need to be accompanied by a practitioner’s wisdom, clinical judgment, and intuition. The result is that we can still “watch” lesions but now do so quantitatively.

Dr. Paul Feuerstein installed one of dentistry’s first computers in 1978. For more than 20 years, he has taught technology courses. He was named “Clinician of the Year” at the 2010 Yankee Dental Congress. A general practitioner in North Billerica, Mass., since 1973, Dr. Feuerstein maintains a Web site ( and can be reached by e-mail at [email protected].

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