The Spin on Low-Speed Rotary Handpieces

By Rebecca Stone March 26, 2019

Not many instruments can send shivers down a patient’s spine in quite the same way that a dental drill does. But without these rotary handpieces, dentists would be up a creek, without, well, a drill.

Low-speed handpieces are typically the go-to instrument for dental office standards such as cavity preparation, caries removal, prophylaxis, prosthetic grinding and trimming, finishing and polishing, and implant and endodontic procedures. They’re said to offer better control and accuracy in preparing smooth margins than would a high-speed handpiece used at lower speeds or with a feathering motion.1

In fact, low-speed instruments are reportedly vital for porcelain adjustments and polishing versus high-speed handpieces, which can introduce microfractures.1

And because they generally operate no higher than 40,000 rpm, low-speed handpieces don’t generate the high levels of heat of which their high-speed counterparts are capable. 2

Electric or Air

Clinicians looking to buy low-speed handpieces must decide whether to go with air-driven or electric units. While Europe skews toward electric handpieces, air-driven handpieces have been ubiquitous in the United States since the 1950s. But electrics are gaining traction in American practices.1

Powered by turbines, air-driven handpieces tend to be less bulky than electrics, as they don’t house a motor. But while they can run much faster than their electric counterparts, due to a lower torque (around 20 watts) they tend to slow down once the bur hits enamel. In addition, noise and vibration, or “chatter,” tend to be more exaggerated with air-driven low-speed handpieces than with electrics.3

In contrast, electric handpieces provide higher torque (around 60 watts) that doesn’t bog down under load. So cutting performance can be more precise. And because of better concentricity and less friction, there is less chance for heat buildup.3

Electrics also sport quieter operation with less vibration. And while they can be heavier than air-driven units because of their motors, their heads may tend to be lower profile than those of air units.3

Many dentists have made the transition from air to electric, and some use both. Although electric units tend to be more expensive than air-driven ones, a look through the literature reveals that due to the ability to drill more quickly with electrics, clinicians are able to see more patients, making up for their initial cost.3

Innovations in Low-Speed Handpieces

In recent years, scores of improvements have made low-speed handpieces the operatory stars they are today. Newer units may feature whisper-quiet, vibration-free operation; trimmed profiles; lighter weights; swivel capability; cordless options; and improved balance.

Perhaps most recently, these handpieces are being designed to minimize the risk of contaminant infiltration and to meet the latest recommendations of the US Centers for Disease Control and Prevention. This is being accomplished through sealed motors; by seamless, lube-free designs; and by fabricating the units so that they can withstand steam autoclave temperatures of up to 275°. 2,4,5

Go the Extra Mile

When prepping teeth with a low-speed handpiece, a system such as the Isolite 3 can be of immeasurable help in providing continuous suction. And thanks to its transparent, flexible mouthpiece, it can prevent dislodged debris from entering a patient’s airway or throat. The system also provides excellent retraction to protect soft tissues from the spinning bur or any generated heat — all while keeping the clinician’s field of view clear and illuminated.

Low-speed handpieces are indispensable assets to the dental operatory. By following manufacturers’ instructions for maintenance, dentists are sure to reap the benefits of these small technological marvels — whether driven by air or electricity — for some time to come.



  1. Bonk J. Tools of the trade: Electric Handpieces For Optimal Precision. Available at: Accessed February 4, 2019.
  2. Stone R. Safe at any speed. Mentor. 2017;8(9):16,18,20,22-23.
  3. Stone R. Power brokers. Mentor. 2016; 7(3):19-21
  4. Stone R. Chain of events. Mentor. 2017;8(12):20-22,24-25. 
  5. Centers for Disease Control and Prevention. CDC Statement on Reprocessing Dental Handpieces. Available at: