Buyers' Guide: Air-Driven Handpieces

The most significant clinical parameters for air-driven handpieces include efficiency, size, ergonomics, bur-switching convenience, and predictable sterilization/disinfection protocols. Handpieces are part of just about every productive practice activity. Thus, their efficacy has a major impact on practice overhead. There are many handpieces that have been developed for particular tasks, to expedite commonly performed procedures. Ideally, they are intuitive, easy to use, and comfortable to manipulate. 

The rotary motor is involved in virtually every procedure that practitioners and auxiliaries perform. Dental handpieces are required instrumentation for virtually every clinical and auxiliary procedure, from prophylaxis to surgery, from occlusal adjustment to crown and bridge preparation. Handpieces are, in fact, the basic clinical tool of the dental practice.

There are several major components to the cost of the dental handpiece. One is the initial cost. Not all handpieces are manufactured equally, and prices vary greatly. High cost does not necessarily mean high quality. The factors to consider are the manufacturing country and the reputation of the manufacturer. Peer recommendation is also important.

The expected service life of the handpiece is a significant contributor to value. The manufacturer’s warranty period reflects the confidence in the product—the longer the better. The practitioner must compare the parameters of the many competing brands.

The manufacturer’s charge for handpiece repair and chuck replacement contribute to the lifetime cost of the instrument. The practitioner can reasonably expect to cycle through several refurbishments before the handpiece is replaced.

The handpiece-bur interface is crucial. The bur must be secure in the handpiece, and rotate concentrically. It must stay firmly in place under extreme clinical conditions, including high torque, significant rotational speed, and extensive vibration. A bur rotating at 4 to 500,000 rpm that flies out of the handpiece can cause serious damage to the patient’s mouth, the dentist’s hands, or both. Rotational concentricity keeps the bur true in the handpiece, cutting rapidly and effectively. Damaged or worn turbines allow burs to wobble during rotation, making the bur path elliptical rather than circular, causing chatter, vibration, and excessive noise. This generates increased perception of pain for the patient and more hand fatigue for the operator.

An often-forgotten feature of air-driven handpieces is adequate torque. Air-driven motors tend to slow down significantly during loading, or the actual cutting phase, when the bur is in contact with the tooth. Dentists have learned to overcome this problem by moving the bur to the tooth to cut, and to draw it back somewhat to allow the torque to build up again. This cycle is repeated hundreds of times for every procedure. The high speed of the air-driven bur is designed to partially compensate for the loss of torque during the load. New technologies that increase the “wattage” of the handpiece produce higher rotational power (and faster cutting). Pressurized systems prevent air-line suck-back, assisting in infection control. Effective braking mechanisms stop the turbine almost instantly once the rheostat pressure is removed, preventing fluid suck-back into the motor.

Bur changing time is nonproductive. The total down time may be one to 2 minutes per bur change. This lost time represents a significant bottom-line loss. Efficient bur changing contributes significantly to clinical speed. Push-button chucking is usually the fastest and most efficient.

Handpiece innovations, facilitated maintenance, and advanced technology are making dental treatment more effective, efficient, and accessible. Advanced design and production permit manufacturers to offer these handpieces at more competitive prices, as well. 

Head Size

Contrary to common belief, handpiece head size and torque are not necessarily correlated. The turbine can compensate for a smaller head size by more impellers. Clinical visibility into the operative site, however, is better with a smaller head, which is more convenient for limited-access posterior procedures and children. Using smaller heads and shorter burs improves patient and dentist comfort. Large and small handpiece heads use the same bearings, hence their comparable service life.

Motor RPM Range

The number of bur revolutions per minute (rpm) indicates cutting efficiency. The stated rpm is measured while the bur is not under functional loading (actually cutting). High-speed air-driven handpieces exhibit a correlation between rotational speed and cutting torque.

Lubrication

Effective regular lubrication significantly enhances the handpiece’s service life. The factory lubrication protocol is best for optimal functional level. Not all lubrication procedures are equally simple. Select a handpiece with a straightforward lubrication process and then ensure that the manufacturer’s instructions are followed regularly and precisely.

Chucking

There are various bur-chucking mechanisms. The selection is up to the dentist (or the team member) tasked with bur changing. Complex chucking protocols are frustrating: look for the simple and time-efficient. More complicated chucking mechanisms are more prone to frequent breakdown. The best selection is a self-contained (push button) chucking process; more efficient, easier to use, while eliminating the need for an intermediary tool that is often thrown out or misplaced.

Air/Water Ports

The air/water mist cools the teeth and oral surfaces as it removes debris to enhance continuous operation with unobstructed visibility. While a single air/water outlet may be adequate, multiple ports offer greater efficiency, better visibility, and less risk of blockage.

Fiber-Optic Illumination

Increased visibility in the operating field is always beneficial. Overhead dental lights may not effectively illuminate the treatment area, and may be limited by direct linear access and further restricted by hand and dental instrument obstruction. Fiber-optic equipped handpieces shine light from less than one cm away, maximizing illumination directly onto the operative site. This facilitates tooth preparation. There is less stress and strain for the dentist and staff. For standardized comparisons, the light intensity of the illumination is measured in lux (foot candles) at the handpiece head.

Handpiece 360° Swivel

A 360° swivel attachment between the handpiece and the hose absorbs and dissipates rotational stresses that can lead to significant operator hand and arm fatigue. Repetitive strain causes cumulative damage over months and years, possibly shortening the practitioner’s career.

Quick Disconnect

Sterilization is mandatory for high-speed handpieces between patients. A quick disconnect saves valuable chairside and assistant time by allowing efficient handpiece replacement between patients.

Sterilization

The average handpiece cycles through the sterilizer 1,000 times per year. Some handpiece models require specified sterilization modes for maximum effectiveness and cost benefit: steam autoclaving, dry heat, or chemical vapor. Never exceed the maximum recommended autoclave temperature that the handpiece components are designed to tolerate. Quality-manufactured instruments will continue to function without noticeable decrease of power or efficiency through repeated sterilizations.

Cartridge Replacement

All handpieces wear and/or break down with extended use. Bearings typically wear out first, but all moving parts are subject to deterioration. The most common and most durable repair involves cartridge replacement, where a brand new turbine assembly completely replaces the old. While there are many qualified handpiece repair services available, replacement price and guarantee research is well worth the time.