Blog Entries - May 2016


Posted on: May 12, 2016

What you need to know when it's time to look for a sonic or ultrasonic scaler

Decision #1: Do you want a sonic or ultrasonic scaler?

Sonic scalers, like the Titan®, are small handpiece-size devices. They sit conveniently in the delivery unit and hook up to a conventional air/water handpiece connector. Research has shown that the tip of a sonic scaler moves in an orbital pattern, tracing the letter "O" as it vibrates at approximately 3,000-9,000 cycles per second.

Ultrasonic scalers involve a power-unit box that sits on the counter. They must be connected to a water source and they plug into an electrical wall outlet. Ultrasonics vibrate at much higher frequencies than sonic scalers (25,000 cycles per second or higher). The pattern of vibration is much more linear than the sonic scaler, tracing the letter "I" or a very narrow ellipse as it vibrates.

The primary difference between sonic and ultrasonic scalers is power. The sonic scaler is a low-power device that removes plaque and fresh calculus. However, it is not terribly effective on heavy calculus, and it is useless on flinty old accretions that can be easily removed with an ultrasonic scaler.

There is an additional advantage to the ultrasonic over sonic. High-frequency ultrasonic tip vibration creates cavitation bubbles in the fluid. When these bubbles contact a surface, they collapse and release energy. Studies have suggested that the energy created by the collapsing bubbles is sufficient to destroy a spirochaete cell membrane. In other words, the ultrasonic spray itself may be lethal to the motile pathogens frequently implicated in periodontal disease.

Though ultrasonic scalers are generally more expensive than sonic scalers, there are some notable exceptions. For example (as we write this), the popular Titan S sonic scaler costs $548 in a mail order catalog. As you can see in the table later in the article, several ultrasonic scalers feature price-tags lower than that.

If you want an ultrasonic scaler, read on.

Decision #2: Do you want a magnetostrictive or piezo ultrasonic scaler?

In magnetostrictive devices (Cavitron®, Parkell, Coltene), tip vibrations are created by a resonating stack of metal strips on the back of the insert.* In piezo devices (EMS, Satelec, Amdent), the vibrations are produced by oscillations of a quartz crystal in the handpiece.

Tip oscillation: For years, it has been generally believed that piezo and magnetostrictive devices differ slightly in the pattern traced by their tips. It is suggested that magnetostrictive tips trace an elongated ellipse while piezo tips trace a linear back-and-forth pattern. Magnetostrictive advocates claim that their elliptical motion is more effective because it generates pathogen-destroying cavitation bubbles 360 degrees around the tip. In contrast, the piezo design creates them only at the two ends of their back-and-forth cycle. Piezo advocates claim that their linear oscillation makes the piezo design less likely to abrade the tooth. If there is a difference in tip vibration between piezo and magnetostrictive designs, it's very subtle — and probably without the clinical importance we manufacturers ascribe to it.

From our work designing and manufacturing ultrasonics, the pattern of tip oscillation appears to be influenced far more by the geometry of the tip itself than by the design of scaler that powers it. For example, S-shaped tips like left- and right-curving perio tips feature an elliptical vibration, but tips with a simple curve, like the Cavitron TFI® and Parkell Universal tip, are linear. In a paper presented at a recent research meeting, independent researchers at the University of Kiel and the Max Planck Institute reported that the vibration pattern of a magnetostrictive scaler seemed virtually identical to that of a piezo scaler. But that isn't to say there aren't significant differences between piezo and magnetostrictive scalers.

Heat: The metal stack in the magnetostrictive scaler generates heat. To prevent overheating, you must scale with plenty of water irrigation. The quartz crystal in the piezo scaler doesn't generate much heat. This means you can run the device with very little water irrigation. On the other hand, because the piezo handpiece doesn't heat the water, patients may complain of cold sensitivity. Note: Some piezo devices feature a separate water warmer to improve patient comfort.

Tips design: Most piezo scalers use proprietary tips designed specifically for that specific brand of scaler. If the manufacturer of your scaler doesn't offer the tip shape you want, or if the scaler manufacturer goes out of business, you're out of luck.

Manufacturers of magnetostrictive scalers would like you to use their inserts in their machines, but the fact is that virtually all brands are interchangeable. Any 25KHz Parkell insert will work in any 25KHz Cavitron scaler, and vice versa. That means owners of magnetostrictive scalers aren't married to a single supplier for their inserts.

Though piezo and magnetostrictive designs each have passionate advocates, both do a fine job of calculus removal. When an independent research association clinically rated every scaler available in the United States, there were piezo and magnetostrictive devices at the top and bottom of the rankings. What's the moral here? It's not whether a scaler is magnetostrictive or piezo that determines whether it's effective, but rather the design of the entire device.

Decision #3: Do you want a 30KHz scaler or 25KHZ scaler?

The number of times the scaler tip vibrates each second is called its "frequency." Most magnetostrictive scalers are either 25KHz (25,000 cycles per second) or 30KHz (30,000 cycles per second.) Studies have proven conclusively that there's no real difference in calculus-removing ability between the two frequencies. However, 30KHz scaling is somewhat quieter, so operators and patients tend to prefer the higher frequency.

Operating frequency is generally hard-wired into the scaler. For example, the Cavitron SPS operates at 30KHz, and only at 30KHz (a 25KHz insert won't even fit into the handle). On the other hand, if you stick a 30KHz insert into a 25KHz device like the Cavitron Bobcat or the Parkell Clean Machine, it'll just spit water, so if you upgrade from a 25KHz scaler to a pure 30KHz device like the Cavitron SPS, you won't be able to use your old 25KHz inserts.

The Parkell TurboSENSOR and Coltene Whaledent Biosonic power both 25KHz and 30KHz inserts. This allows you to use your old 25KHz inserts in the new scaler, and then replace them with 30KHz inserts as they wear out.

  • Clean Machine™ 25KHz — Parkell
  • Clean Machine™ Manual/Auto — Parkell
  • Cavitron Bobcat® — Dentsply
  • Cavitron Select™ — Dentsply
  • Acclean 25KHz — Henry Schein
  • Cavitron® SPS™ — Dentsply
  • Clean Machine™ 30KHz — Parkell
  • Acclean 30KHz — Henry Schein
  • Cavitron Select™ SPS — Dentsply
  • TurboSENSOR™ — Parkell
  • Turbo 25/30™ Two-Handpiece — Parkell
  • BioSonic™ — Whaledent

Decision #4: Do you want an auto-tune or manual-tune scaler?

This question is relevant only if you plan to do extensive low-power subgingival scaling. Early ultrasonic scalers were all manually tuned. When auto-tune scalers were introduced in the late 1960s, they pretty much drove the manual-tune devices off the market. As a result, most manually tuned scalers are now made by specialty manufacturers catering to a niche market.


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