The Five Risk Factors of Improper Ergonomics Kathy Rotramel-Stipe

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The Five Risk Factors of Improper Ergonomics

by Kathy Rotramel-Stipe

Here's a little something for you to try: Sit with your torso completely twisted. Take your right arm and move it horizontally across your body. Tilt your head to the right.

Now stay this way for eight hours, while repairing a watch in your lap.

This is the kind of strain dental professionals place on their bodies each day as they care for patients—a strain that can cause injuries or disorders that affect the body's movement. In fact, according to the American Dental Association (ADA), 29 percent of dental disabilities are related to musculoskeletal disorders (MSDs). Other studies show that about 66 percent of dentists and as much as 80 percent of hygienists suffer some form of MSDs.

Many dental professionals describe symptoms such as aching, burning, cramping, numbness, pain, stiffness, tingling or weakness. How productive can you be if you hurt every day? And how does it affect family and leisure time?1,2

Good posture is imperative for your physical, emotional and even financial health. Fortunately, there is a way to mitigate—and in some cases eliminate—this kind of stress to the body. The first step is recognizing the five risk factors of improper dental ergonomics:
  1. Repetition. We've all heard of carpal tunnel syndrome and repetitive stress injuries. Such injuries are the result of repeated movement. The Occupational Safety and Health Administration (OSHA) defines such movement as "repeating the same motions every few seconds, or repeating motions that involve the same body part more than twice per minute, for more than two consecutive hours."3
  2. Force. Lifting, pushing, pulling, pinching and gripping all qualify as actions of force. This means that simply by performing daily tasks—like scaling patients' teeth—you are adding to the effects of force on the body.
  3. Poor posture. Factors that contribute to poor posture include awkward or static positions, repeatedly raising your arms, working with the hands above the head or elbows above shoulders, bending, and twisting the neck, back or wrists.
  4. Contact stress. Contact stress occurs when force is concentrated on a small area of the body, pinching or crushing the tissue and causing discomfort and often pain. An example is if the body rubs against a component of the workstation, or is continuously in contact with hard or sharp objects such as desk edges or unpadded, narrow tool handles. A suddenly applied pressure, such as compressive force, is also considered contact stress.
  5. Vibration. Using tools or equipment that vibrates for more than two hours per day may lead to hand-arm vibration syndrome.3
Dental professionals face many unique and challenging ergonomic risks. Understanding correct ergonomic techniques and using the right equipment will improve productivity and reduce fatigue and discomfort. Here are a few helpful tips that you can immediately implement.

Fig. 1
Use your head
The average head weighs 10–12 pounds. When perched perfectly upon your neck and shoulders, the body naturally adapts to holding this weight. But if your head is constantly pulled forward, the weight of it strains your neck and places pressure on your spine.

Every inch your head angles forward from its natural position adds another 10 pounds of stress to the neck, shoulders, back and spine. This strains the upper trapezius and can cause serious tissue damage.4,5,6,7

A few ways to minimize extreme forward head position include proper patient positioning, making use of the armrests for support, and using loupes that allow for the most neutral, upright working postures.

Sometimes a clinician may crane his or her neck to the side while wearing a headlamp, to illuminate shadows caused by obstructions. Many doctors believe that loupes with a headlamp will solve their problems. In fact, these tools can cause problems for those who are not instructed on proper use of chair and overhead-light positioning, especially when working on the mandible.8,9

Stay in the power zone
While it sounds like a reference to spending more time at the gym, the power zone is actually the area near the core of your body. Bend your arms at the elbow to a 90-degree angle. The area up to the shoulder and just below the waist is your power zone.

You are much stronger when your hands are closer to your body than when they are farther away. Increasing the distance between the hands and the body increases stress on the lower back, as well as other areas of the body. The more time you can spend working close to your power zone, the less stress and fatigue you will place on your body. In dentistry, we label movements:
  • Class 1—Fingers only
  • Class 2—Fingers and wrist
  • Class 3—Fingers, wrist and elbow
  • Class 4—Entire arm and shoulder
  • Class 5—Twisting of the body 10,11
Your goal should be to eliminate Class 4 and 5 movements and minimize Class 2 and 3 movements. Awareness of your posture and power zone as you perform dentistry will help you feel more comfortable at work and at home.

Practical tips
Begin at the floor and work your way up. Make sure your feet are on the floor (or at least are supported). Keep your knees below the hips, hips under the shoulders, and shoulders under your ears.

Throughout the day, take mini "ergo" breaks to stretch your fingers, wrist, neck, shoulders, low back flexors and hamstrings. Before you begin a new, lengthy task, take 60 seconds to relax deeply and breathe.

Ergonomics professionals often say, "Your best posture is your next posture." In other words, the healthiest thing that you can do for your posture is to keep moving. Move as much as possible and avoid maintaining a static position for an extended period of time. 

Choose the right stool
The unique physical requirements of dentistry pose several challenges to manufacturers who strive to provide optimal seating solutions. Stools that best meet the needs of the entire dental team will excel in the following ways:
  • Adjustability. To provide a great fit, a seat should provide easy movement for seat height and tilt, and back height and tilt. If these adjustments are not simple or the ranges of motion don't match the user's needs, you can't achieve proper access to the oral cavity with minimal stress on the musculoskeletal system.
  • Back support. A great seat should enable and encourage a neutral, S-shaped spine by providing low lumbar support and the right height, angle and forward position compared to the seat pocket. These requirements are very different from the needs of a computer desk user.
  • Seat support. You should experience comfort and security at a slight forward tilt. Do you feel support where it is needed (sitting bones) and relief where it is not (thighs)? Hips should be positioned above the knees to pivot the pelvis forward and position you for a low stress, S-shaped spine (Fig. 1).
  • Dynamic performance. The seat armature should be flexible, to move as the user moves, and encourage slight adjustments that minimize repetitive stress. Seat and thigh pockets are the most important areas to have dynamic rather than rigid support, so that blood flow through the femoral arteries is not inhibited.
Get an assessment
Where do you feel tired at the end of the day? Eliminating your risk factors through proper ergonomics is vital in helping to ensure a lasting career in dentistry.

One idea is to talk with a certified ergonomics assessment specialist (CEAS) for an in-office assessment, to make sure the tools you use are supporting you. The CEAS level of ergonomics mastery is common among physical therapists, and ensures you'll receive OSHA-compliant ergonomics analysis and instruction. These specialists will teach you preventative techniques, including how to:
  • improve positioning of the dental team and patient
  • organize your workspace
  • and simplify work-motion economy.

Your ergonomics assessment will show you how to prevent fatigue and discomfort, and minimize the injury that can lead to work-related MSDs.

Solutions are available to help address the root cause of pain and eliminate risk factors in your office. Be aware. Be proactive. Be comfortable. You—and your team—deserve it.


  1. Sanderson, T. Henry, R. Goldie, MP. (2016) Student Workbook to Accompany Dental Hygiene: Application to Clinical Practice p. 159
  2. Ergonomic assessment surveys - doctors and staff, Roy W. Fried, CEAS I (Certified Ergonomic Assessment Specialist), speaker and co-author of "Ergonomics in Dentistry" series with Ronald W. Porter, PT, CEAS III and Director, The Back School.
  3. and
  4. Eriksen, K. Upper Cervical Subluxation Complex: A Review of the Chiropractic and Medical Literature, p. 229
  5. Goldschmidt, V. Could This Simple Posture Error Wreak Havoc On Your Bone Health?
  6. Livestrong Foundation, Forward Head Posture Symptoms
  7. Chaitow, L. Blake, E. Orrock, P. Wallden, M. (2008) Naturopathic Physical Medicine: Theory and Practice for Manual Therapists and Naturopaths
  8. John Onorato, CEAS (Certified Ergonomic Assessment Specialist), speaker and A-dec Territory Manager
  9. Roy W. Fried, CEAS I, A-dec Territory Manager, co-author of "Ergonomics in Dentistry" series with Ronald W. Porter, PT, CEAS III and director, The Back School.
  10. 6
  11. Four-Handed Dentistry, Part 1: An Overview Concept, Betty Ladley Finkbeiner, CDA-Emeritus, BS, MS

Kathy Rotramel-Stipe Kathy Rotramel-Stipe, senior writer and product communications expert with A-dec, has decades of experience creating internal communications, executive presentations, advertising print and broadcast copy, technical brochures, annual reports and other long-format marketing pieces. She also has more than a decade of experience with a strong focus on web and digital content. In her various roles as communications manager, communications specialist, editor and senior writer, Rotramel-Stipe crafts messages to establish a voice that connects with the target audience.


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