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50 years of seated dentistry: The legacy and the outcome of just sitting down too much

Sept. 20, 2016
Anne Guignon reviews the legacy and the outcome of just sitting down too much while performing dentistry.

By Anne Guignon, RDH, MPH, CSP

When I first started writing this column in 2000, Dr. Esther Wilkins and I had a very interesting conversation. She wondered out loud why so many of today's hygienists were concerned about musculoskeletal disorders (MSDs). From her perspective, there had been a significant increase in complaints. I thought to myself: "Oh, Dr. Wilkins, you just don't understand how hard clinical practice is today." Like many hygienists, I got hurt, and to this day that conversation has haunted me.

If you've ever met Dr. Wilkins, you know she does not miss much. Maybe she thought the new generation was wimpy or prone to complaining. Based on what science is now telling us about the effects of a sedentary lifestyle brought on by excessive sitting, I now believe she was observing a phenomenon that was brought about by the shift to seated dentistry.

In late 2015, an article was published about the 27 most damaging jobs to one's health. The report cited data from the Occupational Information Network (O*NET), a site supported by the US Department of Labor's Employment and Training Administration that contains in-depth information for 974 occupations, including extensive details about how different work settings impact workers' health by increasing their health risks.1

Dentistry takes first place

Kiersz and colleagues analyzed six specific health risks including exposure to environmental contaminants; disease and infection; hazardous conditions; radiation; the risk of minor burns, cuts, bites, and stings; and time spent sitting. Each occupation's health risk score represents a sum total of all combined risk factors. The higher the composite score, the higher the health risks. Sad to say, dental health-care workers had the highest score of all occupations! Our total risk exceeded that of morticians, airline pilots, garbage collectors, and podiatrists!1

While this report seems disheartening at first glance, there is a ray of hope. Even when following all OSHA guidelines, it's hard to eliminate exposure to disease or environmental contaminants such as dust or fumes if we're going to treat patients. But it is possible to change the "time spent sitting" risk factor by changing how we sit in the clinical setting.

Numerous scientific studies over the last 10 years have pointed a grim finger at how sedentary lifestyles affect health risks. Sedentary lifestyles are implicated in the development of more than 30 chronic diseases and conditions.2 Muscles get idle while sitting, and sitting for long periods of time significantly increases the risk for cardiovascular disease, type 2 diabetes, obesity, and metabolic syndrome.3 Metabolic syndrome is also known as sitting disease. A 2008 study conducted at Vanderbilt University found children and adults in the United States spend 55% of their waking hours, or 7.7 hours, in activities that involve sitting at home, at work, and when commuting.4

Obesity is considered a significant risk factor for the development of metabolic syndrome, but a recent study demonstrated that metabolically healthy overweight or obese individuals were less sedentary and more physically active than those who were classified as metabolically unhealthy.5 Obese and overweight young women who are less sedentary and engage in light physical activity are more metabolically healthy and have healthier lifestyle habits.6 In other words, regardless of your weight, keeping active and moving around is important.

Musculoskeletal impact

When sit-down dentistry became the norm in the 1970s, the goal was to improve efficiency, but there were unintended consequences. Dental health-care workers quit moving around; assumed static, awkward postures; and took fewer breaks. Our health risk factors shot up on many levels. Multiple studies have reported a high prevalence of MSDs among dentists7-10 and dental hygienists.11-13 Gupta and colleagues report MSDs can begin to appear while students are still in dental school, 14 information that parallels the findings of a 2012 study of North American dental hygienists15 and a report about Australian dental hygiene students.16 Female students appear to be at higher risk for developing an MSD.10,17

Ergonomists frequently use a tool called Rapid Upper Limb Assessment (RULA) to determine a worker's overall risk for developing a musculoskeletal disorder. RULA has been used to analyze clinical working postures among dental students, concluding that there was a high risk for developing a musculoskeletal disorder.18-20 Kanaparthy and colleagues found students with a low level of postural awareness had a much higher prevalence of MSDs,21 and several studies recommended students receive training while in school to reduce the risk of injury.14,19,20

For the past two decades, numerous studies have reported that dentists and hygienists are at high risk for shoulder and back pain. Our bodies are overburdened from high static muscle activity, upper arm abductions, and prolonged neck flexion caused by bending the neck forward.13,22-24 Providing dental treatment requires higher exertions for the upper trapezius muscles.22,23,25 A recent study by Pope-Ford reported most dentists stand less than 15% of the time, and traditional seating postures contribute to the development of shoulder and neck MSDs in dentists.26

Many dental hygienists and dentists think their exposure to ergonomics in school provided sufficient information to prevent injuries, but the injury rates for all dental health-care workers remain high. Every moment spent sitting on a traditional seat contributes to our overall health risk score. No wonder sitting disease is now referred to as the "new smoking." The resulting impact on your career and earning potential can be devastating. It's time for dental health-care workers to learn about new seating options that support our health. RDH


1. Kiersz A. The 27 jobs that are worst for your health. Business Insider UK/The Independent website. http://www.independent.co.uk/news/business/the-27-jobs-most-damaging-to-your-health-a6718896.html. Published November 3, 2015. Accessed June 30, 2016.
2. Levine JA. Sick of sitting. Diabetologia. 2015;58(8):1751-8. doi: 10.1007/s00125-015-3624-6.
3. Hamilton MT, Hamilton DG, Zderic TW. Role of low energy expenditure and sitting in obesity, metabolic syndrome, type 2 diabetes, and cardiovascular disease. Diabetes. 2007;56(11):2655-67.
4. Matthews CE, Chen KY, Freedson PS, Buchowski MS, Beech BM, Pate RR, Troiano RP. Amount of time spent in sedentary behaviors in the United States, 2003-2004. Am. J. Epidemiol. 2008;167(7):875-81. doi: 10.1093/aje/kwm390.
5. de Rooij BH, van der Berg JD, van der Kallen CJ, et al. Physical activity and sedentary behavior in metabolically healthy versus unhealthy obese and non-obese individuals-The Maastricht study. PLoS One. 2016;11(5):e0154358. doi: 10.1371/journal.pone.0154358.
6. Camhi SM, Crouter SE, Hayman LL, Must A, Lichtenstein AH. Lifestyle behaviors in metabolically healthy and unhealthy overweight and obese women: A preliminary study. PLoS One. 2015;10(9):e0138548. doi: 10.1371/journal.pone.0138548.
7. Alexopoulos EC, Stathi IC, Charizani F. Prevalence of musculoskeletal disorders in dentists. BMC Musculoskelet Disord. 2004;5:16.
8. Ellapen TJ, Narsigan S, van Herdeen HJ, Pillay K, Rugbeer N. Impact of poor dental ergonomical practice. SADJ. 2011 Jul;66(6):272, 274-7.
9. Cho K, Cho HY, Han GS. Risk factors associated with musculoskeletal symptoms in Korean dental practitioners. J Phys Ther Sci. 2016;28(1):56-62.
10. Al-Mohrej OA, AlShaalan NS, Al-Bani WM, Masuadi EM, Almodaimegh HS. Prevalence of musculoskeletal pain of the neck, upper extremities and lower back among dental practitioners working in Riyadh, Saudi Arabia: a cross-sectional study. BMJ Open. 2016;6(6):e011100. doi: 10.1136/bmjopen-2016-011100.
11. Hayes MJ, Smith DR, Cockrell D. An international review of musculoskeletal disorders in the dental hygiene profession. Int Dent J. 2010;60(5):343-52.
12. Hayes MJ, Smith DR, Taylor JA. Musculoskeletal disorders and symptom severity among Australian dental hygienists. BMC Res Notes. 2013;6:250. doi: 10.1186/1756-0500-6-250.
13. Morse T, Bruneau H, Dussetschleger J. Musculoskeletal disorders of the neck and shoulder in the dental professions. Work. 2010;35(4):419-29. doi: 10.3233/WOR-2010-0979.
14. Gupta A, Ankola AV, Hebbal M. Dental ergonomics to combat musculoskeletal disorders: a review. Int J Occup Saf Ergon. 2013;19(4):561-71.
15. 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.

16. Hayes MJ, Smith DR, Cockrell D. Prevalence and correlates of musculoskeletal disorders among Australian dental hygiene students. Int J Dent Hyg. 2009;7(3):176-81.
17. Khan SA, Chew KY. Effect of working characteristics and taught ergonomics on the prevalence of musculoskeletal disorders amongst dental students. BMC Musculoskelet Disord. 2013;14:118. doi: 10.1186/1471-2474-14-118.
18. Petromilli Nordi Sasso Garcia P, Polli GS, Campos JA. Working postures of dental students: ergonomic analysis using the Ovako Working Analysis System and rapid upper limb assessment. Med Lav. 2013;104(6):440-7.
19. Dable RA, Wasnik PB, Yeshwante BJ, Musani SI, Patil AK, Nagmode SN. Postural assessment of students evaluating the need of ergonomic seat and magnification in dentistry. J Indian Prosthodont Soc. 2014;14(Suppl 1):51-8. doi: 10.1007/s13191-014-0364-0.
20. Movahhed T, Dehghani M, Arghami S, Arghami A. Do dental students have a neutral working posture? J Back Musculoskelet Rehabil. 2016;5. [Epub ahead of print]
21. Kanaparthy A, Kanaparthy R, Boreak N. Postural awareness among dental students in Jizan, Saudi Arabia. J Int Soc Prev Community Dent. 2015;5(Suppl 2):S107-11. doi: 10.4103/2231-0762.172950.
22. Akesson I, Hansson GA, Balogh I, Moritz U, Skerfving S. Quantifying work load in neck, shoulders and wrists in female dentists. Int Arch Occup Environ Health. 1997;69(6):461-74.
23. Finsen L, Christensen H, Bakke M. Musculoskeletal disorders among dentists and variation in dental work. Appl Ergon. 1998;29(2):119-25.
24. Noh H, Roh H. Approach of industrial physical therapy to assessment of the musculoskeletal system and ergonomic risk factors of the dental hygienist. J Phys Ther Sci. 2013;25(7):821-6. doi: 10.1589/jpts.25.821.
25. Pope-Ford R, Jiang Z. Neck and shoulder muscle activation patterns among dentists during common dental procedures. Work. 2015;51(3):391-9. doi: 10.3233/WOR-141883.
26. News on the dental ergonomic front-from a professor of industrial engineering. DentistryIQ website. http://www.dentistryiq.com/articles/2015/09/news-on-the-dental-ergonomic-front-from-a-professor-of-industrial-engineering.html. Published September 11, 2015. Accessed June 30, 2016.

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].