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Inside Dental Assisting
Sept/Oct 2012
Volume 10, Issue 5

Ergonomics Awareness

Melissa Tennen

Reduce stress and prevent injuries in the workplace

Dental assistants spend so much of their day caring for their patients’ health—sometimes at the expense of their own well being. Bending, reaching, sitting, slouching, standing, and twisting. These seem like harmless, normal moves for the human body. However, the repetition of these moves with patient after patient, day in and day out, is when they can begin to take their toll.

Maintaining their own health is essential for the health of the dental team and the patients. A healthy and well-trained dental assistant can boost a practice’s efficiency and decrease stress for the team.1 Paying attention to body posture and strain is essential.

In some people, injury from the repetition, force, and stresses may cause musculoskeletal disorders (MSDs). Whether someone develops MSDs depends on a number of factors, such as body, lifestyle, and profession. MSDs are injuries or disorders of the muscles, nerves, tendons, joints, cartilage, and spinal discs.2 Examples of MSDs include sprains, strains, tears, back pain, carpal tunnel syndrome, and hernias.2

The causes of MSDs are complex and diverse and have been a subject of intense debate in recent decades the world over.3,4 Although the issue has been dicussed since the 18th century, the scientific community has only turned up the scrutiny since 1970s.5 In the 1980s and 1990s, the US Occupational Safety and Health Administration (OSHA) performed extensive studies that led to the OSHA Ergonomic Standard in 2000.6 All this to find out the answer to one key question: How do we design workplaces that protect against this type of injury? How do we stay healthy?

Surprisingly, that may be hard to determine. Not everyone with an MSD has risk factors in the workplace, and not everyone who has these risks in the workplace develops an MSD.3,7 The risk factors for MSDs include repetition, force, mechanical stress, posture, vibration, cold temperature, and extrinsic stress.7 Repetition rate is defined by the average number of movements or exertions performed within a given time. This repetition could cause overextension and overuse of particular muscle groups, possibly causing muscle fatigue. Force is the mechanical or physical effort to complete a specific movement. Mechanical stresses are impingement or injury by hard, sharp objects.7

When MSDs occur in the work environment, they are called work-related musculoskeletal disorders, or WMSDs. The work environment and performance of work contribute significantly to the condition or the condition is made worse or persists longer due to work conditions.2 WMSDs account for more than 600,000 injuries and illnesses and 34% of all lost workdays reported to the U.S. Bureau of Labor Statistics.8

Make no mistake. An injury of this nature can have a profound effect on one’s daily life. From buttoning up a shirt to cooking dinner, the toll that a WMSD can take on a person’s life clearly extends beyond the workplace. As many as 85% of dental professionals have pain and discomfort from a musculoskeletal disorder, and 30% are retiring prematurely as the result of a musculoskeletal injury.6

Some risk factors are beyond control. Age, rheumatoid arthritis, renal disease, hormonal imbalances, diabetes mellitus, and hypothyroidism are all examples of predisposing factors for tissue damage and MSDs.7

An Ounce of Prevention

Given all that, how do assistants protect their health? This is where ergonomics come into play. Ergonomics takes into consideration the kind of work that one does, the tools used, and the type of work environment.9 The goal is to reduce stress and eliminate injuries and disorders associated with the overuse of muscles, bad posture, and repeated tasks.10

The dental operatory and office are generally tight work spaces, requiring you to sit, bend, and reach all day—nothing can change that. But what dental assistants can change is how they fit into this space. That’s part of ergonomics.

It is the nature of the dental assistant’s role to help reduce the dentist’s unnecessary motion and decrease twisting and turning.7 The assistant produces a more efficient work environment in what is known as four-handed dentistry. Although the dental assistant’s role is part of the solution to make a more ergonomic solution to the workflow and a more efficient process for the patient, you have your own ergonomic needs.

During the typical appointment, you may need to access the computer, reach for trays and counters of supplies, and move equipment. These activities require bending, stretching, twisting, and contorting.

However, there are ways in which you can both create a more ergonomic environment and take care of your body while you are taking care of patients. One such way is having wide counters that are close to allow for easy reach of materials. Adjustable work surfaces, including platforms on swinging arms, are also good tools to bring objects close but allow for necessary movement by simply swiveling the platform out of the way.11

Mother Knows Best

Your mother was right. Sit up straight. Good posture provides you with more energy, less stress and strain, less distraction from pain, and fewer errors.7 Posture is one of the most frequently cited occupational risk factors.7 Maintaining proper posture is essential,12 but might be more difficult for the assistant, who must work to accommodate other team members.

Keep in mind that the body is not intended to sit in a static position for a long time. The spinal discs require changes in pressure to receive proper nutrients and remove waste products.6 Not only that, but properly balanced posture may reduce cumulative lower back trauma and may control back pain.13

Change your posture, and move by standing or stretching chairside.1 Every hour, stretch your spine, moving backward and forward if you have been standing up straight, or moving in the opposite direction of a posture you have been holding.13

Adjust the height of your seat so that your feet are flat on the floor and your knees are slightly below your hips (thighs are slanted slightly downward). Make sure your thighs are supported.13

The Stool

Dentists used to stand to perform treatment. Four-handed dentistry in the 1960s changed that, and sitting became the preferred way of rendering treatment.7 The dentist is striving to obtain the best access and view to the oral cavity, and the assistant is constantly adjusting to accommodate both dentist and patient. Because of these factors, the stool is a critical part of the balance. Features and benefits of assistant stools should include1:

• Wide range of height adjustability. Cylinder heights vary widely among manufacturers. The cylinder should adjust high enough to avoid the need to lift the arms up and out to the sides.

• Foot ring with adjustable height. Screws should tighten securely to prevent the foot ring from slipping down to the pedestal.

• Torso support bar that ratchets or pivots toward the center of seat pan. Assistants receive support while sitting centered on the seat pan.

• Easy, quick adjustment of torso support bar height allows assistants of various heights to use the same stool and still receive torso support. Avoid models with screw adjustment, which is time-consuming and tedious.

An assistant’s stool should have a broad base pan—square and rectangular—with a tilt to support the buttocks and thighs, including a waterfall-tapered edge.7

Assistants of different heights and sizes will use the same stool—this is an important consideration when choosing a stool. Bear in mind that the torso-support bar, foot ring, or backrest may need to be readjusted with each assistant. A backrest-only design may eliminate readjustment of the torso bar; however, the backrest height may still need to be adjusted.1

When seated, the assistant should maintain neutral position with feet flat on the floor rest. The stool should be height-adjustable to enable the assistant to maneuver easily.7 Assistants should stand for up to half of the treatment time. Alternating between standing and sitting moves the workload from one group of low back muscles to another.1

Exercise Does a Body Good

Your body is built for movement. Part of staying healthy in the work environment is practicing good exercise habits. Along with routinely performing cardiovascular, strength, and endurance exercise, focus on exercises that target the transverse, oblique abdominal, erector spinae, and multifidus muscles.1

Be an Instrument of Change

Making changes in the dental office may be difficult, particularly because investing in new equipment may be cost-prohibitive. Consider making any changes methodically and slowly. Ensure that you and your team are making changes that will make everyone happy and comfortable.7 Haphazard or poorly executed efforts to create a more ergonomically minded work space will not lead to an efficient work environment. Proper planning is pivotal.

An important part of caring for patients is promoting and minding your own health. Watch your posture, encourage your office to purchase equipment such as ergonomic stools, and get plenty of exercise and physical activity.


1. Valachi B. Fighting plaque with a healthy back. How musculoskeletal health can impact a dental assistant’s health. Inside Dental Assisting. 2011;7(5): 12-17.

2. Centers for Disease Control and Prevention Web site. Work-related musculoskeletal disorders (WSMDs) Prevention. Accessed August 11, 2012.

3. Punnett L, Wegman DH. Work-related musculoskeletal disorders: the epidemiologic evidence and the debate. J Electromyogr Kinesiol. 2004;14(1):13-23.

4. Podniece Z; for the European Agency for Safety and Health at Work. Work-related musculoskeletal disorders: prevention report. 2008. Accessed August 11, 2012.

5. National Institute for Occupational Safety and Health. Musculoskeletal disorders and workplace factors— a critical review of epidemiologic evidence for work-related musculoskeletal disorders of the neck, upper extremity, and low back. Accessed August 11, 2012.

6. RGP Dental addresses ergonomic factors affecting dentistry. Inside Dentistry. 2009;5(4):88.

7. Martin MM, Ahearn D, Gotcher J, et al. An introduction to ergonomics: risk factors, MSDs, approaches and interventions. A report of the Ergonomics and Disability Support Advisory Committee (EDSAC) to Council on Dental Practice (CDP). Chicago, IL: American Dental Association. 2004.

8. Occupational Safety and Health Administration Web site. 2014. Prevention of work-related musculoskeletal disorders. Accessed August 11, 2012.

9. Medline Plus Web site. Ergonomics. Accessed August 11, 2012.

10. Centers for Disease Control and Prevention Web site. Ergonomics and musculoskeletal disorders. Accessed August 11, 2012.

11. Cuny E. Understanding and preventing musculoskeletal disorders in dentistry. Inside Dentistry. 2006;2(7):

12. American Dental Association. Ergo tips. Upper back pain. Accessed August 11, 2012.

13. American Dental Association. Ergo tips. Low back pain. Accessed August 11, 2012.

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