With the myriad of dental operator stools and chairs on the market today, selecting the right chair can become a frustrating and daunting task. The choice of proper seating is critical; selection and correct adjustment can either improve or worsen a clinician’s comfort and musculoskeletal health.
Numerous chairs on the market are touted as ‘ergonomic,’ yet one must remember that equipment is only ergonomic if it adjusts to properly fit the operator. Many dental stools and chairs are geared to certain body sizes (often the average European man) and may not adequately adjust to fit all team members. This manufacturing trend is changing in response to the changing demographics of the dental profession, in which increasing numbers of operators are now women.
Based on research and clinical dental ergonomic consulting experience, this article will provide you with guidelines to select the right operator seating for you.
When selecting an operator stool or chair, the following features should be evaluated:
Tilting seat pans help maintain the low back curve—thereby lowering lumbar intradiscal pressures, reducing lumbar muscle strain—and may reduce low back pain. Most dentists and hygienists were taught in school to sit with thighs parallel to the floor, or hips at a 90° angle. However, research reveals that sitting with thighs sloping slightly downward has numerous musculoskeletal benefits and also enables closer positioning to the patient. Saddle style stools open the hip angle to about 130 degrees and position the pelvis to optimally balance the spine, decreasing muscular strain. The Scandex saddle stool is preferred by a majority of team members I’ve worked with; it features a highly padded, medium-width tilting seat. A saddle is especially useful for gaining close proximity at the 9-10 o’clock positions, for short operators, and in confined operatory spaces.
Seat contour can greatly impact the operator’s comfort and support. The front edge of the seat should be highly padded and have a waterfall edge. I do not recommend highly contoured, bowl-shaped seats, as these require that the operator’s buttocks precisely fit the shape to prevent sliding forward on the chair. Perhaps only 15% of my clients fit these chairs well. Crown Seating offers the C70H stool, specially designed for female dentists. It features two different seat and backrest shapes/sizes that can be interchanged for a custom fit.
Seat pan depth should support most of the operator’s thigh. When seated all the way back in the stool, the operator should be able to easily fit at least three finger widths between the edge of the chair seat and the back of the knee. Dental operator seat pans range from 14 inches to 17 inches deep. For taller operators (over 5’8”), the Orascoptic Bodyguard chair has a deeper seat pan and sturdy armrest construction. The Royal R044, Link 185MSL, and new Brewer ErgoFlex chairs have shallower seat pans (14”) and are recommended for average to shorter operators (under 5’5”). The ErgoFlex is much lighter in weight than its predecessor, the Alleviate.
Backrests should easily adjust forward to support the operator’s lumbar curve in a balanced upright, seated posture. A problem in dentistry is that the dentist is often in contact with the backrest only one third of the time. Crown Seating solves this problem with its innovative new design—the C80D chair features a tilting seat and backrest that move with the operator.
Cylinder height of the chair is an important consideration that can impact the operator’s seated posture and, therefore, their musculoskeletal health. Fitting a stool with a short or tall cylinder may allow certain operators to better maximize the ergonomic benefits of the stool.
Currently, there is no height standardization for cylinders in dental operator seating. For example, the Brewer ‘medium’ height cylinder is comparable to many manufacturers’ ‘short’ height cylinder. Most operators over 5’7” will require a tall cylinder when purchasing a Brewer chair.
A common problem among tall operators is sitting too low, which flattens the lumbar curve and may cause low back pain. Make sure your thighs slope downward when your chair is at the highest cylinder adjustment.
Shorter operators often sit perched on the edge of the chair, due to a cylinder that will not adjust low enough. Brewer ErgoFlex and Dentech Advance stools offer extra-short cylinders.
Armrests are helpful in reducing neck pain and may also reduce low back discomfort for operators of all heights. Movable fixed armrests (Orascoptic Bodyguard), movable armrests (Brewer Alleviate) or swivel armrests (Link 185MSL) are recommended.
Dentists should also consider alternating between a saddle stool in one operatory and a traditional stool with armrests in another operatory to spread the workload between different groups of muscles throughout the day. Operators should ask to trial a chair before purchasing it to assess how it fits their specific needs. However, even a well-designed chair or stool can detrimentally impact one’s musculoskeletal health if it is improperly adjusted for an individual’s body stature.