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Dr. Bethany Valachi, PT, DPT, MS, CEAS is DPR’s ergonomics editor and author of the book,“Practice Dentistry Pain-Free” and clinical instructor of ergonomics at OHSU School of Dentistry in Portland, Ore. She is also the author of the evidence-based "Online Dental Ergonomic & Wellness System for Dental Professionals." A physical therapist who has worked exclusively with dental professionals for more than 15 years, she is recognized internationally as an expert in dental ergonomics, and has been invited to lecture at more than 300 conferences worldwide. She has published more than 50 articles in peer-reviewed dental journals and has developed patient positioning and exercise DVDs specifically for dental professionals. Bethany offers free newsletters, articles, videos and product reviews on her website at www.posturedontics.com and can be reached at firstname.lastname@example.org.
The secret to preventing occupation-induced pain isn’t so secret after all - in fact, it’s the most natural thing you can do.
According to a 2010 study, women who sit more than six hours each day have approximately a 40-percent higher death rate and men a 20-percent higher death rate than those who sit fewer than three hours a day. This isn’t good news for dentists, who tend to sit in excess of six hours during an average eight-hour day.
The human body was designed for movement. Over thousands of years, the human body has depended on movement for its survival. But industrial and technological advances have done much to impede Mother Nature. With the onset of the Industrial Revolution, increasing numbers of workers perform relatively stationary tasks. With the advent of computers, the number of sedentary jobs has increased, as have the number of musculoskeletal disorders. One study showed the prevalence of low-back pain has increased by 2,700 percent from 1980 to 1993. It’s reasonable to infer that changes in the way we use our bodies has contributed to this dramatic increase in work-related pain. In short, the body must move - and move properly - to stay healthy.
Since the introduction of seated (four-handed) dentistry, dentists tend to work for longer periods of time without taking a break and they perform longer procedures. Consider that when you sit in a static operating posture without leaning on your chair’s backrest, more than 50 percent of your body’s muscles must contract to hold the body motionless while resisting gravity. The static forces resulting from these prolonged, static postures are much more taxing on the body than dynamic (moving) forces.
Movement is imperative in your operatory to decrease the structural damage from prolonged, static postures. You can incorporate the following four movement strategies to help you move the workload from one group of muscles to another, prevent painful muscle ischemia and reduce static spinal disc loading.
1. Change operating positions
Moving frequently between 8 and 12 o’clock positions around the patient’s head is important; every time you move around the patient’s head, the workload shifts slightly from one area in your body to another. Your clock position will largely depend upon which position enables you a line of sight that’s perpendicular to the occlusal surface. The 11-12 o’clock positions provide the most neutral, ergonomic operator posture and should be utilized whenever possible.
A common ergonomic error among dentists is not positioning the patient properly when working on the upper arch, causing forward leaning and twisting. The occlusal plane of the upper arch should be up to 20 degrees backward in relation to the vertical plane. Patient tolerance to this positioning can be dramatically improved with specially designed positioning aids.
2. Switch stools
Research shows that regularly changing your seated posture can reduce low back pain. Consider placing a traditional stool with armrests in one operatory and a saddle-style stool in another. The saddle stool will place the dentist halfway between standing and sitting, which uses different muscles than traditional seating and also decreases spinal disc pressure (Fig. 1).
Saddle stools have additional ergonomic benefits. By placing the pelvis in a neutral position, the natural spinal curves are more easily maintained. Since they open the hip angle, saddle stools are ideal for gaining close proximity in the 9 o’clock position, (especially helpful when working with wide patient chairs) and a good choice for dentists with short torsos who frequently find themselves working with elevated arms. Saddle stools allow for lower positioning of the patient and a more relaxed arm and shoulder posture. They’re also very easy to move around the patient’s head and great for confined operatory spaces.
3. Alternate between standing and sitting
One study reveals that dentists who alternate between standing and sitting have less low-back pain than dentists who worked solely in a seated position. Dentists tend to spend more than three-fourths of their total working hours seated, which places increased pressure on the lumbar discs.
Consider standing for extractions, exams, denture adjustments, injections and impression making (Fig. 2). You’ll need to ensure that your patient chair elevates to a height that enables a neutral standing posture when working. When standing, and especially for extractions, the mouth should be just below elbow level.
4. Chairside stretching
Chairside stretching is the only operatory ergonomic intervention that addresses every microtrauma resulting from prolonged, static postures (Fig. 3). Research reveals that taking frequent breaks and moving are integral to an effective injury prevention program and pain control in dentistry.