Modern electric handpieces feature improved benefits for today's dental surgeon.

About 60 years ago dental handpiece technology was in transition. Theretofore, dentists had been using slow, noisy, and laborious electric "drills" for cutting tooth tissue. These caused considerable trauma, and were often mechanically troublesome. The old electrics were quite inefficient. But, new air turbine handpieces were reaching the profession. They were a huge improvement over the old electrics.

The pneumatic handpieces were eventually perfected to the point where they would run smoothly, when not under load, at speeds in excess of 400,000 rpm. For decades, such handpieces have been the standard cutting instrument for general dental work. It has been realized for some time, however, that air turbine handpieces have significant disadvantages. As regards asepsis, cutting efficiency, and speed control, the air turbine handpiece possesses unfavorable characteristics.

Air turbine handpieces depend largely on momentum for their power. When placed under load they quickly slow to 100,000 rpm or slower. Since the air turbine handpiece is not driven by a specific and "connected" power source, it is necessary to use the handpiece in a "touch and go" fashion to maintain reasonable efficiency. The electric system, however, is driven directly by its power source. It does not materially slow down under load. Excellent power can be maintained, which drives the electric motor. Motors of 40,000 rpm (quiet, efficient, and cool running) are now available. Simple attachment of a 1:5 speed increaser handpiece, for example, delivers bur speed up to 200,000 rpm.

The air turbine is either on or off--either running at full speed or not at all. Moreover, the true rpm rate of the cutting instrument, under load, is neither measurable nor predictable. It depends on airflow efficiency, amount of load applied, etc. An electric system, however, can be variably controlled from a low rpm rate to full speed. The rpm rate can, furthermore, be measured and registered on the unit so the operator knows the speed of his instrument at all times. If the instrument, for example, is registering an rpm rate, which should be providing excellent cutting efficiency, but the instrument is not in fact cutting efficiently, the operator thereby immediately knows that the cutting instrument is dull, and needs to be replaced. Such an advantage is not available with air systems. Digital readouts of bur speed are readily provided with modern electrical systems.

The modern generation of electric motor, handpiece, and cable assembly can be easily dismounted for sterilization. With the most modern motors, steam autoclaving is an acceptable and efficient means of sterilization. Older electrical systems could not be sterilized at all; and many air turbine systems have the same liability. The autoclavibility of electrical systems is a huge advantage for the dentist, and should be adopted without hesitation.

Present electric technology delivers to the dental practitioner cutting instruments that are more efficient than air turbines can supply. Cavity preparation is quicker, more precise, and less traumatic with modern electrical technology than is possible with air turbines.

Moreover, electrical systems are quiet. The characteristic loud hissing noise of the air turbine should soon be a thing of the past; replaced by the quiet, consistent, efficient electrical systems.

Improved asepsis is a huge advantage with electric handpiece systems. When an air turbine is turning at fall speed, it aerosolizes saliva and blood, sending it flying throughout the entire dental operatory, even if relatively efficient intra oral vacuum is being used. As we have noted, however, the maximum rpm rate of the electric handpieces is much slower. Therefore, the electrics are guilty of much less aerosolizing. That, in turn, means that the potential for irrigating the environment with bacterial and viral contaminants is substantially reduced.

"I'm very interested in keeping compressed air out of the patient's mouth," declared Dr. Robert J. Miller (dentist and asepsis researcher in Pleasant Hill, California). "When dentists and implant surgeons are working in a bloody field and applying the air turbine and water, they can spray enough plasma into the air in one minute to spread 200,000 hepatitis virus particles. Electric handpieces reduce this hazard to almost nothing."

Another rare, but potentially lethal problem with air turbine handpieces is the possibility of air embolism. If air is leaking from a pneumatic system in an improper fashion (sometimes caused by wear or poor engineering), that air--under pressure--can be driven into the vascular system of the patient when areas of open bleeding are present. If that happens, fatal embolism can occur in less than one minute. The use of electric handpieces, with no air under pressure being utilized, completely eliminates this hazard.

Some electrical systems provide the practitioner with sterile water or saline, to be used as a clinical irrigant during procedures. But modern technology has not been able to offer any practical or economical means of supplying such clean irrigant coincidentally with modern pneumatic dental equipment. The pneumatic systems, conversely, require the application of a relatively high volume of water direct to the cutting site, to reduce frictional heat.

The controlled, efficient, autoclavable electric motor and handpiece combinations are today the standard cutting instruments in endodontics, implant surgery, and periodontal surgery. As manufacturers progressively increase the efficiency of electric motors, and decrease their coincidental heat output, these systems are rapidly becoming the standard of choice for general dental applications as well.

We have come fall circle. The profession abandoned electric technology decades ago because it was then inefficient and unacceptable. Air turbines have served the dental profession relatively well for more than half a century. However, now, electric technology has improved to the point where the former problems with electric handpieces are only a bad memory and the new systems offer advantages which air turbines cannot match. Electric systems are now the preferred technology for all aspects of dental practice.

[check] Controllable rpm

[check] Digital Readout 

[check] Cool Running

[check] Quick & Quiet

[check] Dismountable

[check] Autoclavable

[check] Improved Asepsis

Douglas Kazen is Board of Directors Chairman and Director of Corporate Development at Aseptico International--a manufacturer of high precision dental products that include a broad range of electric motor systems designed for dental and medical applications. He can be reached at 800-426-5913 or [e-mail].