Power Brokers

We’re all familiar with that sound. The dental drill emits a high-pitched whine like nothing else on Earth, and can send shivers down the spine of even the most intrepid dental patient. But thanks to ongoing innovations in dental handpieces, the source of one of dentistry’s most prevalent clichés may soon become a distant memory.

When it comes to restoring teeth, the handpiece, or “drill,” is still a necessity. The two players in the dental handpiece market are those that are air-driven, through use of compressed air and air turbine engines, and those that are electric, featuring motors, control units, driveshafts and gears. Most modern handpieces of either type are equipped with water spray and illumination systems, offer 360-degree swivel capability, and provide bur-locking mechanisms and an easy way to change out various head attachments.

While both types are undergoing constant improvements, and each, in both low- and high-speed forms, has an important place in the best-equipped operatories, a majority of dentists in the United States employ air-turbine handpieces. It’s what most of them were trained on in dental school. But there are a number of reasons it may make sense for clinicians to add an electric drill to their armamentariums.

AVOIDING BURNS

LUCKY BUSINESS/ISTOCK/THINKSTOCK

Electric handpieces have been associated with inflicting serious burns on patients, typically on the inner cheek. In fact, in 2007, the U.S. Food and Drug Administration issued a warning to oral health care professionals about serious burns caused by poorly maintained electric handpieces.6 But according to the American Dental Association (ADA), other factors are also at play.

The ADA stresses that when operating electric handpieces it is important to follow manufacturer instructions, to operate with the chip water turned on (which refers to the air through the waterline that creates a cooling mist), and to avoid depression of the handpiece cap, which can occur if the patient’s inner cheek is pressing up against it.7 In response to these issues, some of the most recent electric handpiece iterations are being engineered with technology to limit heat buildup to a cool 98.6 degrees.

 QUIETER OPERATION

Electric handpieces, long popular in European practices, are indeed making inroads into U.S. practices. Because air-driven units are typically the source of drill screech, this is good news for patients. The offending noise is caused by compressed air moving through the turbine when activated, producing a super-high rotational speed. Think of a 747 jet airplane — inside your head — and you get the idea. On the other hand, electric handpieces rely on motors for operation. In fact, a common claim among dentists who use the latest versions of electric handpieces is that they are “whisper quiet” compared to their air-driven counterparts.

But pleasing patients isn’t the only benefit of quiet operation. From an ergonomic standpoint, it can help salvage the hearing of the clinician. According to a number of sources, including a recent report by the Association of General Dentistry, studies indicate that clinicians subjected to the sound (in some cases reaching as high as 102 dB under load) of a high-speed drill day in and day out, are at risk of hearing loss. Proper equipment maintenance and hearing protection are suggested as ways of counteracting this.1,2 Or practitioners could reach for an electric drill, which emits sound levels at around 55 dB. It should be noted that some of the newer air turbines are said to match this, though most still deliver higher decibel ratings.

POINT of SALE

BENEFITS FOUND IN ELECTRIC HANDPIECES

  • Brushless motors eliminate carbon dust cleanup and the need to replace brushes as they wear.
  • Seamless construction helps keep handpieces clean and allows easy sterilizing.
  • Improved concentricity results in less vibration for smoother and more precise cutting and margins.
  • Faster cutting equals less heat buildup.
  • Higher torque means no stalling under load.
  • Noise reduction.
  • Variable-speed control via dial or foot pedal.
  • Can accommodate pretty much any head attachments.
  • Allow reverse operation, a necessity in endodontic work.
  • Easily integrate with existing air systems.

 CUT THE CHATTER

Lower decibel levels aren’t the only advantages offered by electric handpieces. They are also said to produce less vibration by way of improved concentricity. Concentricity means that the bur in the handpiece is spinning true, which means it’s centered. This is said to provide stellar precision, a smoother cut and enhanced patient comfort.

Conversely, a wobbling bur can be due to ball-bearing wear and result in bur chatter — and worse. Unfortunately, as they wear, air-driven handpieces sometimes create bur chatter when cutting through dense material. The vibration can reportedly be intense and quite uncomfortable for the patient.

SPEED AND TORQUE

Primary among the beneficial features of electric handpieces are superior speed and torque. The two are inextricably linked, and are responsible for producing the cutting power needed in both high- and low-speed applications. Speed for handpieces is measured in revolutions per minute (rpm), while torque is often expressed in watts (W) or in Newton centimeters (Ncm).

Typical speeds for high-speed air-turbine handpieces range from around 250,000 to 420,000 rpm — and higher. This sounds pretty impressive compared to the fact that most high-speed electrics top out at 200,000 rpm.3 But the reality is that air-driven units lack torque, with most delivering between 16 and 23 W of power (with the exception of one, said to offer 30 W) compared to up to 60 W dished out by electric handpiece setups.4

The upshot is that air units have long been known to slow or stall under heavy load (when pressure is applied or when cutting dense materials) due to limited torque, sending that high rpm into a virtual free fall.3 For this reason, clinicians using air-driven handpieces become accustomed to applying a light touch in a stroking motion, referred to as “feathering,” to maintain the required speed for the job.

Conversely, the beefy torque of electric units not only can get the job done, but allows constant operation, regardless of load. They now also feature variable speed control, allowing both low- and high-speed operation.5 This all means they are quite capable of quickly cutting any material, including the all-ceramic materials many dentists are using today.

LEXICON

  • Concentricity: Spinning evenly on an axis
  • Decibel: A measure of sound level
  • Torque: A measure of the force it takes to move something around an axis
 The main criticisms leveled at electric handpieces are that they are more expensive than air-driven units as well as heavier and bulkier. But as this technology continues to evolve, designs are becoming more streamlined, better balanced, and lighter, thanks to materials such as titanium being used for housing and the introduction of short micromotors and miniheads.4 Some low-speed handpieces are even available as highly portable, battery-operated units. And, as time goes on, prices are bound to drop. In fact, clinicians already using electric units will say that because they can drill more quickly and more precisely, they are able to see more patients, which makes up for the cost difference in the long run.

For these reasons and a host of others, if you have customers who have not yet felt the power of an electric handpiece, why not offer them a chance to test drive one or encourage them to try them out at the next dental show? By helping to broker an investment in these little powerhouses, you’ll be doing your customers, their patients and yourself a favor.

 REFERENCES

  1. Theodoroff SM, Folmer RL. Hearing loss associated with long-term exposure to high-speed dental handpieces. Academy of General Dentistry. Available at: agd.org/media/271978/GenDent_MJ15_Folmer.pdf. Accessed February 14, 2016.
  2. American Dental Association professional product review. An ADA Laboratory Evaluation: High-speed Air-Turbine Handpieces. Available at: ada.org/en/publications/ada-professional-product-review-ppr/archives/2015/vol_10_iss_1/high-speed-air-turbine-handpieces. Accessed February 14, 2016.
  3. Kurtzman GM. Handpieces: The Drill on High Speeds. Contemporary Esthetics and Restorative Practice. Available at: endoexperience.com/filecabinet/Endo%20Related%20Restorative%20Dentistry/handpeice%20comparison%20kurtzman%20product%20advances%2010-05.pdf. Accessed February 14, 2016.
  4. Blaes JA. Are Electric Handpieces Ready for You? Dental Economics. Available at: dentaleconomics.com/articles/print/volume-95/issue-2/features/are-electric-handpieces-ready-for-you.html. Accessed February 14, 2016.
  5. Paquette C. Forward Progress. Mentor. September 2013;4(9): 32–36.
  6. U.S. Food and Drug Administration. FDA Public Health Notification: Patient Burns from Electric Dental Handpieces. Available at: www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm062018.htm. Accessed February 14, 2016.
  7. American Dental Association professional product review. A Laboratory Evaluation of Electric Handpiece Temperature and the Associated Risk of Burns. 2014. 9;2:18–24. Available at: ada.org/~/media/ADA/Publications/PPR/PPR_VOL_9_ISS_2_2014_R1.pdf. Accessed February 14, 2016.

MENTOR March 2016;7(03):19–21.

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