Prior to the 1960s, dental clinicians practiced standing up with the patient in a sitting position. They struggled with body pain as they bent and twisted their bodies around to gain access to the patient’s mouth. When sit-down dentistry was introduced, clinicians were given a flat stool and told to lay the patient supine to relieve their back pain.
Seventy years later, that back pain hasn’t gone anywhere. Considering that between 68% and 100% of dentists still report body pain,1,2 they clearly missed the mark. Yet, we’re still practicing the same way.
Of the two variables that were changed, standing wasn’t the real culprit. Moving the field of vision into a different plane (in front of the clinician with the mouth facing upward) was a stroke of genius—until they seated the clinician into that flat, round stool 100% of the time.
The solution is eliminating both awkward posture and static posture, two of the major risk factors for workplace injury.3
The problem with flat stools
When using a flat stool with the thighs parallel to the ground, studies show a significantly higher degree of lumbar kyphosis (flattening from L1–L5) than with standing.4 The lumbopelvic-hip complex, which connects the lower half of the body to the upper half of the body, is where traditional flat-seat-pan sitting causes problems. When moving from a standing position to a sitting position, the pelvis tucks under to place the glutes down onto the seat.
Dental professionals take it a step further and perch on the edge of their stool, increasing intervertebral pressure on the discs by 90% (nearly double that of standing neutral) while also shortening the psoas/hip flexor muscle.5 When sitting in this position for long periods of time (an hour or multiple hours a day), the pressure can “bulge” discs, while tightening the psoas muscle. This is the low back pain we so often feel at the end of the day or from a long car ride.
Enter saddle stools
For decades, dental ergonomics specialists have been promoting the use of saddle stools for the benefits of keeping the legs down at a nearly standing angle of approximately 135º, by way of preventing the above process from occurring in addition to gaining closer proximity to the patient. Without the legs directly in front of the clinician, there is less obstruction to get in close to the patient, which prevents leaning over. Saddle stools for the win, right? Yes, absolutely!
But there’s more to it than that.
We need movement
Static posture, established through isometric contraction of muscles, is an equal participant in body pain for dental clinicians. To reduce static posture, we need movement. Microshifting, or the distribution of body weight from one foot to the other, for example, reduces static posture.
When we reintroduce part-time standing dentistry with supine patient positioning, the game has completely changed. The clinician who stands has 0% additional intravertebral disc pressure (standing is neutral), the psoas muscle is exactly the length it should be, and the variation in posture is no longer static, using less energy and gaining the ability to microshift.6 This also decreases chronic joint compression, which prevents the inflammatory processes that begin when oxygen, innervation, and nutrients (blood supply) are prohibited from getting to the limbs through the joints. This prevents musculoskeletal disorders. Humans weren’t meant to sit or stand in static positions. We were meant for constant movement—even small ones.
One hiccup with standing dentistry is having a patient chair that elevates high enough for the taller clinicians. It’s better to lean in 10º than 60º, but ideally the patient chair should be able to raise high enough to get the oral cavity to elbow height with the forearm in neutral. (See figure 1, a Forest 6400 by DentalEZ with a height cap of 35”.)
The benefits of standing during clinical practice are profound for efficiency, effectiveness, and health. We move from clock position to clock position with much more ease, making us faster. We can get as close as we need with nothing to obstruct our space. Many feel the lack of obstacles leaves them feeling less fatigued. Not being chronically tired is shown to have ripple effects, from case acceptance rates to relationship interactions across the board. Who doesn’t benefit from having more energy?
Sit part time, stand part time
So, stand full time? Not exactly. The feet can get sore from standing all day, especially later in the week. As a dental ergonomic specialist, I recommend the best of both worlds: stand part time and sit on a saddle stool part time. Dental hygienists should stand for every other patient, and dentists should stand for all hygiene checks, quick fills, and most restorations on the anterior teeth to begin with. Dental assistants should stand when possible, depending on patient height requirements for the doctor. This style of practice allows for variation in posture that may even provide clinicians with a few spare moments to stretch or get a drink of water!
Editor’s note: This article first appeared in Clinical Insights newsletter, a publication of the Endeavor Business Media Dental Group. Read more articles and subscribe.
References
- Soo SY, Ang WS, Chong CH, Tew IM, Yahya NA. Occupational ergonomics and related musculoskeletal disorders among dentists: a systematic review. Work. 2023;74(2):469-476. doi:10.3233/WOR-211094
- Cho MH, Kim MJ, Kim EH, Kim TH, Oh S. Ergonomic dental chair design for dental care providers' movement. J Phys Ther Sci. 2018;30(8):1064-1066.
- Hayes M, Cockrell D, Smith DR. A systematic review of musculoskeletal disorders among dental professionals. Int J Dent Hyg. 2009;7(3):159-165. doi:10.1111/j.1601-5037.2009.00395.x
- Sielatycki JA, Metcalf T, Koscielski M, Devin CJ, Hodges S. Seated lateral x-ray is a better stress radiograph of the lumbar spine compared to standing flexion. Global Spine J. 2021;11(7):1099-1103. doi:10.1177/2192568220939527
- Andersson BJ, Ortengren R, Nachemson A, Elfström G. Lumbar disc pressure and myoelectric back muscle activity during sitting. I. Studies on an experimental chair. Scand J Rehabil Med. 1974;6(3):104-114.
- Valachi B, Valachi K. Practice Dentistry Pain-Free: Evidence-Based Strategies to Prevent Pain and Extend Your Career. Posturedontics Press; 2013.
