One Size Does Not Fit All

The Issue of Ergonomics—Ergonomics is technically an applied science concerned with product designs and arrangements that maximize efficiency and safety. However, in practical terms, it boils down to matching tasks to the people performing them. Ergonomics is an issue in nearly all aspects of life, especially since the advent of the computer age. Computer use has contributed greatly to an increase in repetitive motion–related conditions, and the widespread recognition of terms such as carpal tunnel syndrome. However, ergonomics is especially relevant to the design and use of the handpieces used frequently in dental offices.

Compromises and Coping Strategies—Practitioners considering the purchase of any type of equipment for their practices should keep in mind basic principles of ergonomics as they relate to their ability to practice while minimizing discomfort due to fatigue, or risk of injury due to overexertion. This may mean sacrificing torque for comfort, or having numerous handpieces for different tasks, using those that add undue stress or strain only if necessary. Perhaps most important for clinicians is making sure to thoroughly understand one’s own needs, as well as the capabilities and limitations of a given piece of equipment. The only way to know for certain is to test it in the office, and make sure the manufacturer will permit its return if it ultimately just does not feel right.

Just as dentists and their patients come in all sizes and weights, so do handpieces.

Overall size: The electric handpieces that have gained popularity with their significant power and torque also have a lot of weight, making them heavy, even in the hands of the typical male dentist. However, for many smaller doctors—particularly females, whose numbers in the profession are growing—these handpieces may not fit well in their hands, and may lead to fatigue and general discomfort.

Head: Handpiece head size comes into play in a variety of situations. Although the value of a small head is its ability to provide access—eg, into the mouths of pediatric patients—it can also offer greater comfort to the operator. However, its impact on visibility should also be considered—for example, whether the head size of a short shank bur enables the practitioners to use it with adequate visibility, or might it interfere with how the bur interacts with tooth structure?

Grip: A short shaft lightens the weight of a handpiece that might otherwise be too heavy, but a longer one lightens the grasp, improving tactile sensitivity and reducing fatigue. A wider-diameter grip in the posterior is designed to provide a more relaxed hand position. Related to grip is texture—grips with ribbing or another type of texture enable the practitioner to maintain control while grasping the handpiece lightly.

Balance: Another aspect of how a handpiece feels is balance. Its weight should be evenly distributed to reduce fatigue, which is especially problematic for operators with small hands. To properly evaluate balance, the practitioner should demo it with proper tubing attached.

Visualization/lighting: Several factors affect the operator’s ability to visualize the area of interest, including the illumination provided by the handpiece. For example, some handpieces feature fiberoptics that add concentrated lighting to the operating field, and lighting that doesn’t require additional wiring because the air used by the rotary instrument powers it via its generators. However, another consideration is how the water spray is being delivered to the bur, and its impact on visualization.

Angle: Ergonomically aware practitioners should keep in mind that maintaining a neutral wrist position can minimize strain, making the angle of the handpiece an important consideration. A contra angle design is preferable, and is available on all high-speed systems, although straight attachments are currently more popular.

Swivel: Another ergonomic consideration for handpiece selection is swivel, without which the wrist must generate all movement, subjecting it to additional fatigue.

There’s more to handpiece selection than the instrument itself. It must be designed to fit the existing workflow and layout of the operatory.

Hose/tubing: Make sure these attachments are lightweight and flexible. Rear delivery system cords and hoses are known to exert pressure on shoulders, arms, wrists, and fingers.¹ Proper patient positioning, good body mechanics, correct seating, and ergonomic operatory design can address these risk factors.

Cordless handpieces, which are not restrained by a hose, make it easier for the practitioner to maintain the desired neutral wrist position, but they need to otherwise blend in with the entire system the clinician/practice already has in place.

Connection: Consider how the handpiece is disconnected and reconnected. Will it fit on standard handpiece connection or does it need a different kind of connection? Will it fit on a four- or six-hole adaptor, so it can be used in any room? These issues all affect the ability of the entire staff to safely and efficiently handle and interact with the equipment.

According to Ergonomics-Info.com, ergonomics is the science of designing jobs, equipment, and workplaces to fit workers. In addition, proper ergonomic design is necessary to prevent repetitive strain injuries, which can develop over time and lead to long-term disability.²In dentistry, risk factors include: repetitive movements, poor flexibility, incorrect positioning, insufficient breaks, weak postural muscles, prolonged awkward postures, and improperly adjusted equipment.³

Low back pain, repetitive stress injuries (RSI) such as carpal tunnel syndrome, and various other musculoskeletal disorders (MSD) are such a significant problem among dentists that the American Dental Association’s Ergonomics and Disability Support Advisory Committee (EDSAC) delivered a report to the Council on Dental Practice (CDP). The resulting document, An Introduction to Ergonomics: Risk Factors, MSDs, Approaches, and Interventions,⁴ focuses on ergonomic risk factors, the various types of MSDs, and practical approaches to ergonomic issues in the workplace. In addition to providing background on ergonomics to promote awareness, it proposes specific steps relative to ergonomic concerns that “are designed to make the practitioner both more comfortable and more productive.”⁴

Given that the primary objective of ergonomics is to prevent work-related musculoskeletal disorders, or symptoms that aggravate them—including repetitive tasks, such as scaling and root planning or using awkward postures to access the oral cavity—clinicians need to adopt positions that enable them to achieve optimal access, visibility, comfort, and control at all times.⁵

Part of achieving this objective is selecting tools and equipment that reduce force and exertion and keep the hand/wrist in the desired neutral position.³ Therefore, for the selection of handpieces, they should choose lightweight, balanced models—preferably cordless—that provide sufficient power, built-in light sources, and swivel mechanisms. In addition, handpieces should offer ease of operation and maintenance, and if there are hoses, they should be lightweight and pliable.

To minimize the risk of injury and disability related to ergonomic issues—both inside and outside the work environment—preventive guidelines for reducing stress include: to the greatest extent possible, avoid repetitive tasks and awkward positions, including hand movements.¹ Those who must engage in such stressful tasks should take frequent breaks and regularly perform stretching exercises, including those specifically designed for the RSI-prone.⁶