Have a seat: Ergonomic conversations turn to dental clinician seating

Aug. 26, 2015
If you have read many of my columns throughout the years, you're bound to know that there are some central themes:


If you have read many of my columns throughout the years, you're bound to know that there are some central themes:

  • Understand the risk for a workplace-related musculoskeletal disorder (WRMSD) is high
  • Use equipment that fits your body, such as a saddle stool
  • Invest in custom-fitted equipment such as loupes
  • Pace yourself and take breaks throughout the clinical day
  • Establish a good savings plan, contributing to your retirement fund regularly
  • Take care of your physical, mental, and spiritual needs

Each goal above goes a long way to creating and supporting a happy, healthy career.

If you graduated more than 10 years ago, you received little advice on the physical rigors of dental hygiene practice. Most of us never dreamed that thousands of hygienists would develop such a wide range of physical disorders - and with injury rates that far surpass those of the general public. Most lay people think our hands are the highest risk for occupational injury. But studies indicate neck injuries are at the top of the list. Depending on the study, between 63% and 89% of all hygienists report neck injuries or discomfort.1-4 Some studies discount discomfort, but nagging aches and pains are classic symptoms of an injury in the making.


Other articles by Guignon


Shoulder injuries are at epidemic levels - between 60% and 70% - followed by reports of pain and injuries in the lower back,3,4 mid and upper back, dominant hand, and finally the non-dominant hand.1-4

While the overall risk of developing one or more WRMSDs is an alarmingly high at 51% over the life of a clinical career, there have been dramatic changes in the academic world over the past 10 years. Prior to that time, there was little discussion about the ergonomic postural benefits that could be gained from using properly fitted magnification loupes.4

Today, many schools require students to use magnification during their clinical training. When loupes are made with the correct working distance4-6 and declination angle, magnification loupes eliminate awkward neck postures, which is the main reason loupes need to be custom fitted. Many now purchase headlights, eliminating shoulder stress created by constantly adjusting the overhead light.

Operator seating

Operator seating is part of the most recent conversation. Traditional operator stools are made to fit a 5'11" tall man, a standard sizing specification adopted during World War II. Without strong scientific support, these specifications became the norm throughout the seating industry and this carried over into the design of dental equipment, since most dentists were men at that point in time.

Despite the fact that most dental hygienists are women and 50% of today's dental school graduates are female, most equipment is still designed for tall men. Until recently, dental hygienists were expected to use whatever equipment was in the office, whether it fit or not.

Traditional stools are fraught with problems for many of us. First, the seat pans are too large or too deep, causing many to sit on the edge of the chair, virtually ignoring the lumbar support. But let's examine the lumbar support, which is really a poor answer to counteracting lower back issues. When sit-down dentistry came into vogue in the 1960s, clinicians needed a stool. They borrowed the round, marshmallow-on-a-stick design favored by physicians. But physicians spend a few minutes sitting during a patient exam, while dental processionals spend upward of an hour or more delivering care while using static seating postures.

Many seat pans on traditional stools have a very defined, hard edge where the seat pan top meets the edge of the seat, which cuts off the circulation in the back of the leg. Most seat pans are designed so the user's thighs stay parallel to the floor.7

Most of us were taught to sit this way, but this position forces the pelvis to rotate up and forward into a non-neutral position. This posture flattens the natural lumbar curve in the spine, doubles the compression on the intervertebral discs in the spine, and forces the back muscles to support the torso, substantially increasing physical fatigue. Sitting in a traditional stool, hour after hour, day after day, can and will take its toll on the user's back.8-12

Deep seat pans and low seating positions increase the distance from the clinician to the patient, forcing clinicians to work with outstretched arms, resulting in an arm abduction that creates stress on the entire shoulder girdle. Ideally, clinicians should position their torso as close to the patient as possible, using a seat height position that places the patient's head waist high. This type of position keeps the forearms parallel to the floor and close to the body, again favoring a neutral position.9-11

Saddles on the other hand allow clinicians to sit tall and up close with our legs spread apart, creating a tripod between our torso and lower limbs. Saddles seats are trimmer and need to have both an overall height and seat pan tilt adjustment.

There are several saddle designs. Most people do very well with a modified English seat pan,9-11 which looks like a warped Frisbee. Those with a narrow pelvis, tight hip flexor muscles, or who ride horses typically prefer a Western saddle, which has a pronounced hump in the middle, and keeps the user's legs closer together.

The new Denver saddle from Crown Seating is a cross between those two styles and the dynamic saddle features a small backrest, which is handy when one wants to sit back and have chat with a patient. Thousands of clinicians are now using saddles. There are conversations all over the Internet how a properly fitted and adjusted saddle has helped people feel better and work better in their comfort zones. RDH

Chelsea's story: Hard to believe

Last week, a well-composed email arrived in my inbox, requesting the handout from a recent CE course that covered the ergonomics of healthy seating. Given the benefits of using a saddle to achieve a comfortable sit/stand position, it's really hard to imagine a dental hygienist could or even would be reprimanded for purchasing her own saddle to use in the clinical setting.

So Chelsea's story, full of twists and turns, came as a real shock.

Chelsea graduated eight years ago and has been practicing full time for the last seven years in the same dental office, which also employs three other full-time hygienists. This busy office has been working with a practice management firm for several years. In 2013, the hygiene coach encouraged all of the hygienists to purchase their own equipment and provided training on how and why to use a saddle. Chelsea chose to purchase loupes and a light after that session.

Chelsea started having circulation problems in the back of her legs using the traditional operator stools. When the stools were reupholstered with a very slick vinyl called ultra leather, she started sliding off the edge of the stool. For safety reasons, she switched to using an assistant's seat that did not have an arm.

Her interest in using a saddle seat grew after the ergonomics course, and she mentioned to her employer that she would be looking at saddle options at the next dental meeting. The employer did not voice any objections to her plan. She then placed an order at the meeting for the saddle that fit her personal physique.

Just like her previous purchase, Chelsea never expected her employer to pay for the saddle and was totally blindsided when he objected to her using it, claiming if she got injured using a saddle he would be liable and that clinicians should sit with their thighs parallel to the floor, just as they were taught in school. He also stated that saddles did not work for his body and he could not use one.

What? This was Chelsea's saddle, not his. Without warning, Chelsea was ordered to meet with the doctor and the office manager in closed meeting, where she was told that disciplinary action would not be taken against her at this time and that she had to provide a doctor's note to be able to use her saddle in the office.

Two days later, she was informed there would be another closed meeting at the end of the day. At this meeting, she was told she could not use any personal equipment without prior authorization of the doctor. If she did so, she would face disciplinary action and possible dismissal. Chelsea offered to waive all liability against the doctor if she sustained any injury related to using the saddle in his office, but he refused her offer. Instead an ergonomic specialist and a physical therapist would be brought in to review Chelsea's need to use alternative seating.

Like most hygienists, Chelsea is focused on providing quality patient care, and she is also willing to purchase equipment that will support that goal. She is also aware of the tremendous risk for developing a WRMSD, so purchasing custom equipment that fits her body is part of her personal professional career plan. It's obvious that Chelsea's saddle is just an excuse. It's sad to hear about another employer using bullying tactics to get their way with the staff. While the final chapter is still up in the air, Chelsea's story rocked my comfort zone to the core. It's unlikely that Chelsea will remain in this practice much longer. No one deserves treatment like this.


1. Hayes MJ, Smith DR, Cockrell D. Prevalence and correlates of musculoskeletal disorders among Australian dental hygiene students. Int J Dent Hyg. 2009,7(3):176-181.
2. Hayes MJ, Smith DR, Cockrell D. An international review of musculoskeletal disorders in the dental hygiene profession. Int Dent J. 2010 Oct;60(5):343-52.
3. Hayes MJ, Smith DR, Taylor JA. Musculoskeletal disorders and symptom severity among Australian dental hygienists. BMC Res Notes. 2013 Jul 4;6:250.
4. Guignon AN, Purdy CM. Dental hygiene 2012 - workplace demographics, practice habits, injuries and disorders, academic awareness and professional attitudes. Unpublished data collected October/November 2012. www.surveymonkey.com/s/5K8.
5. Congdon LM, Tolle SL, Darby ML. Magnification loupes in US entry-level dental hygiene programs - Occupational health and safety. JADHA. 2012 Summer; 86(3):215-222.
6. Maillet JP, Millar AM, et al. Effect of magnification loupes on dental hygiene student posture. J Dent Educ. 2008 Jan;72(1):33-44.
7. Valachi B, Valachi K. Mechanisms leading to musculoskeletal disorders in dentistry (2003). J Am Dent Assoc. 134 (10): 1344-1350.
8. Levine JM. What are the risks of sitting too much? http://www.mayoclinic.org/healthy-living/adult-health/expert-answers/sitting/faq-20058005.
9. Mandal AC. The Seated Man (Homo Sedens), Applied Ergonomics,12.1, p. 19. Oxford 1981.
10. Tiedeman J. New concepts in seating. Accessed atontent.statefundca.com/pdf/sftySeatingConcepts.pdf on June 15, 2014.
11. Mandel AC. Balanced seating posture on a forward sloping seat. Accessed at http://www.acmandal.com/ on June 15, 2014.
12. Wang PC, Ritz BR, Janowitz I, et al. A randomized controlled trial of chair interventions on back and hip pain among sewing machine operators: the Los Angeles garment study.

ANNE NUGENT GUIGNON, RDH, MPH, CSP, provides popular programs, including topics on biofilms, power driven scaling, ergonomics, hypersensitivity, and remineralization. Recipient of the 2004 Mentor of the Year Award and the 2009 ADHA Irene Newman Award, Anne has practiced clinical dental hygiene in Houston since 1971, and can be contacted at [email protected].