In Europe, 80 percent of doctors use an electric handpiece. In the United States it's 30 percent. We thought electric was going to be the thing and that everybody would upgrade to an electric handpiece. While the traditional air-turbine dental handpiece continues to be the dental drill of choice for many dentists, the electric dental handpiece is rapidly gaining ground. And for good reason. It offers superior cutting efficiency, regardless of the material, and quieter operation. Plus, many contemporary electric dental handpieces are backwards compatible with existing air-delivery systems, making the transition from air to electric a breeze.
Comparing Air and Electric Dental Handpieces
There are two types of dental handpieces: air-driven and electric. In an air-turbine handpiece, air pressure drives a turbine, which spins the dental bur, or cutter. With an electric handpiece, a drive shaft attached to an electric motor operates the bur.
The two types differ in terms of speed (expressed in revolutions per minute, or RPM) and cutting force, or torque.
While an air-turbine handpiece can operate at higher speeds compared to an electric handpiece, the rotating speed drops as much as 40 percent when the bur comes into contact with the material it is cutting. It is the resistance that the bur encounters that causes a subsequent drop in speed and cutting force.
Unlike an electric handpiece with its electric motor and drive shaft assembly, the air pressure in an air-turbine handpiece cannot overcome the increased cutting resistance. An electric handpiece maintains consistent, high-cutting force, even at lower rotational speeds. The effect is greater cutting efficiency across a variety of material densities, as well as reduced operating noise.
Factors to Consider When Evaluating a Dental Handpiece
When evaluating different handpieces, keep your needs and the needs of your patients at the forefront. Important factors to consider include noise and concentricity, both of which affect patient comfort, gear ratios, and ergonomics.
Concentricity refers to how tightly the dental bur turns on its axis as it spins. A dental handpiece with low concentricity tends to wobble as it spins. Look for a dental handpiece boasting "exceptional concentricity," "reduced bur wobble," or "less bur chatter."
A patient in the dental chair experiences bur wobble as discomfort at the drilling site. Otherwise known at bur chatter, the phenomenon is more common with air-turbine handpieces and can arise when the bur transitions from one material to another, like when working to remove a crown.
The typical high-speed,air-turbine handpiece has a noise output of between 70 and 80 dB, while the typical electric dental handpiece puts out 55 to 60 dB of noise. Choose a dental handpiece that offers noise reduction, as any reduction in noise output reduces a patient's anxiety.
Interpreting Gear Ratios on Electric Dental Handpieces
Each electric handpiece comes with the gear ratio stamped into it. The gear ratio is expressed as X:Y and identifies what procedures the dental handpiece can perform.
For ultra-low speed procedures like endodontics and pin placement, there are dental handpieces with gear ratios like 10:1 and 16:1.
At a dental convention, take the opportunity to visit manufacturers' booths to try out how a dental handpiece feels in your hand. Electric handpieces feel heavier in the hand when compared to air-turbine handpieces. Test the grip with a gloved hand. Textures vary from glossy and smooth to a textured surface with bumps and grooves to enhance grip.