Sleight of Hand

Injuries can occur throughout the body, but the most common type of injury experienced by oral health professionals is musculoskeletal disorders (MSDs). These include injuries or pain in the joints, ligaments, muscles, nerves and tendons of the limbs, neck, back, and hands. According to the American Dental Association, typical causes include body position, overexertion, soft-tissue compression and repetitive motion. Many ergonomic experts report that working out of balance is an important factor in the development of MSDs. Working in such a fashion puts strain on one or more body parts. And, unfortunately, when even one part of the body is out of whack, like a post-collision freeway pileup, other parts are bound to be affected.

Numerous studies have shown that dental professionals are at a particularly high risk of developing work-related MSDs, with some reporting that up to more than 95% experience MSD-related pain.1–4 In some cases, the pain was so severe that clinicians were prevented from working. One study also looked at how dental specialties related to the location and rate of MSDs, and found that rates of back and hand pain were significantly higher among dental hygienists and endodontists than for those in other specialties.4

Hands can be particularly vulnerable due to the requirement for dental professionals to perform detailed work with hand instruments and vibrating handpieces, using precise hand and wrist movements. Performing that sort of work in the tight space of an oral cavity is challenging enough, but when you consider taking that work into the even smaller space of a root canal, or performing the exact same procedures day in and day out, it is easy to see how endodontists and hygienists might be at a higher risk for MSDs than some of their counterparts. And, although also a trouble spot for dentists,3 MSD symptoms manifesting in fingers of hygienists is reportedly one of the most prevalent reasons for missing work.4


Point of Sale | The Right Stuff

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  • Sharp instruments are must-haves in the dental office for those wishing to avoid musculoskeletal disorders.
  • Lightweight, well-balanced instruments designed with padded, rounded handles at least 10 mm in diameter are recommended as good ergonomic choices.
  • When it comes to selecting instruments, customers can benefit from variations in diameter, weight, texture — and a perfect fit.
  • Cordless equipment and visual aids, such as loupes, can foster good ergonomics.
  • Gloves must fit each individual without binding or sagging.

“Due to the repetitive motions of many dental and dental hygiene procedures combined with awkward postures, musculoskeletal problems in the wrist and hands are very common,” says Lisa Moravec, RDH, MSDH, an assistant professor and West Division site coordinator at the University of Nebraska Medical Center College of Dentistry in Lincoln. In fact, studies indicate that repetitive movement is the predominant cause of MSD symptoms.4

Unfortunately, when proper ergonomics are not practiced, the likelihood for injury is compounded. This can certainly end up taking a bite out of a practice’s bottom line and, worse, end careers. Indeed, according to Howell Tapley, PT, MSPT, PhD, associate professor and director of the Doctor of Physical Therapy Program, Sycamore Center for Wellness and Applied Medicine, at Indiana State University in Terre Haute, “Hand and arm disorders are the most common cause of disability in dentists and dental hygienists.” Tapley notes that dental hygienists appear to be especially at risk, reporting pain in the neck, shoulder, and hand and wrist areas more than other dental professionals. “Estimates are that 20% of dental hygienists experience general musculoskeletal problems, and up to 8% may have carpal tunnel syndrome,” he reports.

COMMON DISORDERS

Carpal tunnel syndrome and tendinitis are two of the most common hand injuries in the dental profession. Carpal tunnel syndrome results from pressure on a nerve in the wrist, which may be caused by fluid or narrowing of the space around the nerve. Though the actual cause is often unclear. Symptoms include numbness, tingling and pain. It can also weaken grip.

Besides carpal tunnel syndrome, Moravec says, “Some of the most common injuries among dental practitioners that involve the wrist and hand include tendinitis, nerve compression or entrapment syndromes — typically of the ulnar or radial nerves — and De Quervain’s tenosynovitis, which is inflammation of tendons around the base of the thumb.”

Tapley additionally points out a common form of arthritis that can develop. “Osteoarthritis of the thumb is a condition common in women and may be related to overuse. The condition occurs in the trapeziometacarpal or ‘basal’ joint, located at the base of the thumb, less than an inch distal to the wrist, and may occur in as many as 25% of post-menopausal women.”

Splinting, steroid injections and surgical release of the ligament are all possible solutions for carpal tunnel syndrome and similar disorders. But another treatment option is to change the ways hands are used to avoid these disorders in the first place.

STRATEGIES TO PROMOTE HEALTHY HANDS

While there is no shortage of ergonomic health hazards for dental practitioners to negotiate, there are steps they can take to circumvent potential career-ending disasters. For example, changes in technique and style may be called for to support hand health in clinical settings. “Using a neutral wrist position, proper grasp, and good posture, as well as reducing risk factors through use of ergonomic instruments help control or prevent hand injuries,” Moravec advises.

Melanie Simmer-Beck, RDH, PhD, a professor and admission enhancement program director of Dental Public Health and Behavioral Science, at the School of Dentistry at the University of Missouri-Kansas City, agrees. She stresses that providers should be mindful of posture and strive to maintain a neutral position. “The roots of the median and ulnar nerves start in the neck, travel through the arm, and end in the fingers,” she explains. “The nerve can be compressed in an area different from where a practitioner is feeling pain or numbness. Are you bending your neck around to see inside the patient’s mouth? Do you have enough light? Each time a muscle is overused it causes a small injury to the musculoskeletal system. It is possible to have multiple injuries in a single day. These add up. By the time practitioners start feeling pain, it is too late, and significant, irreversible damage has occurred.”

Tapley says that both manual and ultrasonic scaling have been shown to create significant biomechanical stress on the body, therefore increasing risk of injury. “Maintaining neutral joint positions protects joint structures,” Tapley says. “Avoiding excessive flexion and extension of the wrists while scaling may reduce the risk of injury.”

Using the hand as a unit may reduce stress on the fingers and wrists, Tapley suggests, as well as using both hands together, whenever possible, to help reduce the strain occurring on soft tissues. “Stretching the wrists and hands regularly may reduce the risk of injury, as well as avoiding forceful pinching or gripping,” says Tapley. But he also advocates the taking of frequent breaks and simply listening to one’s own body as ways to avoid injury.


Lexicon

  • Entrapment: Relates to pressure exerted on a nerve.
  • Ergonomics: The study of people at work.
  • Musculoskeletal disorder: The Centers for Disease Control and Prevention defines MSDs as injuries or disorders of the muscles, nerves, tendons, joints, cartilage, and spinal discs.
  • Osteoarthritis: A common form of arthritis, in which joints suffer cartilage loss.
  • Radial nerve: A nerve that runs along the underside of the arm.
  • Ulnar nerve: A nerve that runs from the wrist to the shoulder.

Tapley and others advise using sharp instruments. “This reduces the force required to complete a task, as well as the number of repetitions,” he explains. Using sharp instruments might seem like a pretty obvious concept, but it is often overlooked. Says Simmer-Beck, “When scaling, it is critical to have instruments that are sharp — really sharp. Using dull instruments requires more muscle activity and can lead to overuse.”

But Simmer-Beck also notes that the kinds of instruments used play a major role in ergonomics for hands. “Instrument selection and condition can affect how dental providers practice and the muscle activity needed to complete a task,” she says.

ERGONOMIC DESIGNS

Manufacturers have really stepped up their game in the creation of ergonomically designed products and equipment that can help take the strain off hands. Tapley notes that the use of large-diameter handles and lighter-weight instruments may reduce excessive pinch force required to complete tasks. In fact, studies show that factors such as handle diameter and shape, and instrument weight definitely impact upper extremity pain. For instance, one study found that handles with tapered, round shapes and at least a 10 mm diameter did, indeed, demand the least muscle load and pinch force during simulated periodontal work.5

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In another study, researchers determined that although no ideal length of instruments was established, the optimal diameter was found to be at least 10 mm and the optimal weight 15 g or less. In addition, handles featuring padding was reported to decrease muscle activity. Researchers concluded that use of a variety of instrument handles based on the optimal parameters is the best course of action.6

As one of the latter study’s authors, Simmer-Beck explains, “One concept that can be applied across the board is the importance of using a variety of instrument handles that vary in diameter, weight, and texture. This creates a working environment where you are not in a static position overusing one or two muscles.”

Moravec agrees, adding, “The selection of hand and mechanical instruments does play a role in preventing injury. Instrument design considerations include handle diameter, weight, texture, and whether it has balanced working ends. For mechanical instruments, such as handpieces and ultrasonic units, consideration of weight, vibration, and drag from cords are factors in determining selection for improved ergonomics or limiting risk factors.”

To Moravec’s last point, manufacturers are increasingly offering cordless handpieces. Besides enhancing portability between operatories, such units eliminate the resistance caused by power cords, which may exacerbate MSDs in hands. But they also help by speeding up the process. The use of cordless handpieces can greatly reduce the time spent polishing, and, by extension, reduce muscle workload, if not intensity. Cordless units are said to be steadily gaining favor among dental hygienists.7

OTHER FACTORS

Among other variables, lighting and visual acuity have also been found to have ergonomic ramifications concerning the rest of the body when performing the kinds of exacting tasks required of dental practitioners. Says Tapley, “Wearing loupes is associated with fewer complaints of MSDs, as is ergonomics education.”

But those with whom we spoke also note the overarching importance of gloves — and not just as barrier protection. For instance, says Tapley, “The use of gloves may reduce harmful vibration with the use of mechanical devices.”

But because the range of gloves available can be mind numbing, Simmer-Beck’s advice can go a long way in helping sales representatives to best serve their customers who are grappling with glove selection. She recommends having clinicians ask themselves a few questions when purchasing gloves: Do they fit comfortably? Are they too tight? Are they too loose, requiring a tighter instrument grip? Are the gloves positioning your thumb in a non-neutral position? These are important considerations when choosing gloves. After all, the work is demanding enough of hands without the added stress of fighting poorly fitting gloves.

The significance of finding gloves that fit, well, like a glove, as well as instruments that are ideally sized in proportion to the operator’s hand cannot be overemphasized. As Simmer-Beck cautions, “Hand ergonomics must be customized for each individual. There is no ‘one-size-fits-all’ solution.” And that is probably the most important thing to keep in mind when it comes to avoiding these particularly damaging sleights of hands.

References

  1. Hayes MJ, Smith DR, Cockrell D. A systematic review of musculoskeletal disorders among dental professionals. Int J Dent Hyg. 2009;7:159–165.
  2. Sartorio F, Vercelli S, Ferriero G, D’Angelo F, Migliario M, Franchignoni M. Work-related musculoskeletal diseases in dental professionals: 1- prevalence and risk factors. G Ital Med Lav Ergon. 2005;27:165–169.
  3. Kierklo A, Kobus A, Jaworska M, Botulinski B. Work-related musculoskeletal disorders among dentists — a questionnaire survey. Ann Agric Environ Med. 2011;18:79–84.
  4. Estrich CG, Caruso TJ, Guninger SE, Pleva D. Musculoskeletal complaints among dental practitioners. Occupational and Environmental Medicine. 2014;71(Supplement 1):A50.
  5. Dong H, Loomer P, Barr A, Laroche C, Young E, Rempel D. The effect of tool handle shape on hand muscle load and pinch force in at simulated dental scaling task. Appl Ergon. 2007;38:525–531.
  6. Simmer-Beck M, Branson BG. An evidence-based review of ergonomic features of dental hygiene instruments. Work. 2010;35:477–485.
  7. McCombs G, Russell DM. Comparison of corded and cordless handpieces on forearm muscle activity, procedure time and ease of use during simulated tooth polishing. J Dent Hyg. 2014;88:386–393.

Featured Image by REDHUMV/VETTA/GETTY IMAGES PLUS

From MENTOR. December 2017;8(12): 34-36,38-39.

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