Good Vibrations

June 1, 2009
“Is it live or is it Memorex?“ You may remember those ads where the opera singer broke a glass with her voice.

Paul Feuerstein, DMD

For more on this topic, go to and search using the following key words: resonant frequency, implants, apex locator, intraoral lights, LED, Dr. Paul Feuerstein.

“Is it live or is it Memorex?“ You may remember those ads where the opera singer broke a glass with her voice. The shattering glass happens due to a physics effect called “resonant frequency.“ Go to and search for this term for an explanatory video.

When tapped, the crystal wine glass rings with a specific note. If this exact note is produced near the glass, it vibrates “in sympathy.“ If the note gets louder, the glass vibrates more until it breaks. You can also see this if you stand next to a piano and sing a note into the strings. The matching tone will vibrate (but the piano will not crack)!

Osstell AB from Sweden (not to be confused with implant company Osstem in Korea) has created a device to test the stability and integration of implants using RFA (resonant frequency analysis). The study was done on 45 implants that were checked for integration with radiographic and clinical tests. The implants that were thought to be sound had a higher frequency than those recently placed or not integrated.

The logic is that if a stick is embedded in concrete and “twanged“ like a guitar string, it will have a higher frequency than one in Styrofoam or mud. Osstell's new device, the ISQ, is a simple system that requires the dentist to remove the healing cap, screw in a “Smart Peg“ (the stick), and then turn on the frequency generator, which is placed next to the peg. The meter will read the resonant frequency of the peg, and register a value from 1 to 100. The higher number is a higher frequency, thus it is more integrated.

This is particularly valuable if you are doing an immediate load case, and wonder if the implant is stable at the initial placement. You also can easily follow the progress over time as an implant integrates.

As usual, if you choose to incorporate this technology, you still have to follow other traditional clinical methods. It is no different from using a caries detection system in conjunction with radiographs and clinical judgment. Information is on the company's Web site at An Internet search will give you more reports and articles.

Another interesting electronic device is a new apex locator from MedicNRG. The principals in this Israeli company have been in this arena for many years, and actually developed the circuitry used in many of today's apex locators.

They have come up with a new compact (under 50g and small enough to fit in a pocket) unit that has an accuracy to 0.1 mm and works (while automatically adjusting) for dry, wet, or bleeding canals. The basic unit, ApexNRG-xfr, has a series of LEDs that light up in sequence, with sound, every 0.25 mm, indicating when you are at the apex. The new model, ApexNRG-Blue, has the LEDs but also can transmit information via Bluetooth to your computer.

The software gives a graphic representation of the file in the canal in real time, so you can see where you are — much like a GPS system. Since this unit is so small, the company is working on a version that will attach directly to your handpiece and read the apex right through the file.

MedicNRG also has a portable, battery-operated LED light, LumiNRG, which allows a standard mirror head to be attached and delivers a bright light for exams. This includes the sometimes difficult denture sore spot. Information is on the company Web site at

In fairness, there are two other small intraoral lights that I have found to be successful. One is from HighQ Dental, a manufacturer of many headlights, including the new Starbright, as well as a clever head-mounted video camera, the ALOS. HighQ's Oralume, a disposable LED light that lasts about 20 hours, comes with a transillumination tip and a standard mouth mirror. The light is inexpensive, and is sold in a starter pack of three and replacement packs of 10. Information is at

The other is from Addent, which manufactures the MicroLux Transilluminator. The tip design focuses the light through an autoclavable glass rod that can find fractures in enamel, canals in the chamber, and more. The company has a mirror attachment and a new illuminated perio probe that enables easier reading in the arch's darker corners, as well as a thin tip that can be placed down a root canal or in a cavity preparation for viewing of fractures or caries. Addent also offers an array of composite placement aids, including a cartridge warmer (Calset) and a novel new composite dispenser. The company also has a color correction intraoral light (Rite lite). Check out these and more products at

My recent trip to the IDS meeting in Cologne showed me many new and innovative products. Stay tuned.

Dr. Paul Feuerstein installed one of dentistry's first computers in 1978. For more than 20 years, he has taught technology courses. A mainstay at technology sessions, Dr. Feuerstein is an ADA seminar series speaker. 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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