Aim for less strain, less pain in the dental hygiene operatory

by Anne Nugent Guignon, RDH, MPH

Clinical dental hygiene is a hands-on process of care, one that can't be outsourced. While many of our tools have changed over the last 100 years, our hands are still an integral part of the procedures we perform. Until the day a magic mouth rinse is developed that prevents biofilm from forming, dissolves calculus and stain and creates homeostasis in the oral cavity, we're going to be using tools that create stress on our fingers, hands, wrists, forearms and elbows.

What we do in the clinical setting creates nightmares for ergonomists, the smart folks that are challenged to create healthy workspaces. Our bodies take a beating trying to overcome the cumulative effects of tasks that involve repetition, force, vibration, awkward postures and static positions. Other factors include working in a confined space with limited visibility, compromised lighting and poorly designed equipment placed in hard-to-reach locations.1,2

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The dental hygiene treatment room is not an optimal work station by any standard. Crowded, malpositioned teeth, strong tongues, tight cheeks and lower anterior teeth that have a lingual tilt also restrict access. Add in tense, anxious patients, production demands, rigid schedules, fidgety patients and it's a wonder that we make it through the day. There are also increasing numbers of hygienists who are now able to provide care outside the four walls of a traditional dental office, creating even more challenges for our mobile colleagues.

In a 2012 study, 733 North American dental hygienists reported having developed one or more musculoskeletal disorders/injuries. Of those who had MSDs, thirty-six percent indicated issues with their dominant hand. Many in this convenience poll also had problems with their non-dominant hand, thumb, fingers, elbows or forearms.3

When dental hygiene started, the tools were quite basic. Today there are many design choices for scaling and polishing, but the key is to keep the wrist in a neutral position and utilize a light grasp. Neutral position means the hand has 100% of its strength to perform tasks. Extending the wrist 45 degrees from neutral decreases strength by 20%, and 60-degree flexion results in a 55% reduction in strength. Radial and ulnar deviation also compromise strength. Radial deviation at 25 degrees causes a 20% reduction, and a 40-degree ulnar deviation reduces hand strength by 25%.⁴ Combining forceful hand exertions with awkward hand wrist postures for more than two hours a day increases the risk for developing an MSD. 5

Back in the dark ages, hand instruments were classified as either anterior or posterior and had skinny handles, often without textured surfaces, which increased our pinch grip when moist. We were taught to fulcrum on the tooth next to where we were scaling, a nearly impossible task in the posterior. The toll on our fingers, hands, and wrists altered many careers and lives.

Textured, large diameter handles and slim compact blade designs improve access. Sharp instruments facilitate a light touch.6,7 In the world of power scaling, there are now tip designs that rival some of the slimmest probes, making it easier to fully integrate ultrasonic scaling into most appointments.

Clinicians now realize that so-called posterior instruments often provide better access to malpositioned lower anterior teeth. A right or left ultrasonic scaling insert tip keeps the wrist neutral and allows access to lingually inclined teeth. Power scaling reduces tedious, forceful hand and finger movements.

Contemporary handpieces are lightweight, balanced and many have fully integrated swivel mechanisms. Newer handpiece hose materials are flexible and weigh much less. Cordless polishers eliminate drag and weight, allowing neutral wrist postures. Three companies now offer cordless polishing devices.

Prophy cups with external ridges facilitate polishing. Soft cups adapt with less pressure, petite cups improve access, and flexible pointed polishers fit into overlapping areas and under orthodontic brackets.

While you may think that you're not at risk for developing an MSD because you only practice part time or actively seek out ways to reduce physical stress, remember that clinical practice is only a part of what you do. Household tasks, leisure activities and keyboarding also put your hands at risk.⁸

Select your tools and products carefully, and learn each tool's specific attributes. Create your own comfort zone by reducing stress to your body. The end result is a longer and more satisfying career. RDH

1. Pascarelli EF, Hsu YP. Understanding work-related upper extremity disorders: clinical findings in 485 computer users, musicians, and others. J Occup Rehabil. 2001 Mar;11(1):1-21.
2. Nordander C, Ohlsson K, et al. Risk of musculoskeletal disorders among females and males in repetitive/constrained work. Ergonomics. 2009 Oct;52(10):1226-39.
3. Guignon AN, Purdy CM. Dental hygiene 2012 - workplace demograph-ics, practice habits, injuries and disorders, academic awareness and professional attitudes. Unpublished data collected October/November 2012. https://www.surveymonkey.com/s/5K87Z25.
4. Costello K. Laboratory workers commonly report work-related musculoskeletal disorders from the use of manual pipettes. Laboratory Safety News. 2004.
5. MSD risk assessment – 2011. Safe Workplace Promotion Services Ontario. www.wsps.c
6. Dong H, Loomer P et al. The effect of tool handle shape on hand muscle load and pinch force in a simulated dental scaling task. Appl Ergon. 2007 Sep;38(5):525-31.
7. Laroche C, Barr A, et al. Effect of dental tool surface texture and material on static friction with a wet gloved fingertip. J Biomech. 2007;40(3):697-701.
8. Hedge A, James T. Gender effects on musculoskeletal symptoms among physician computer users in outpatient diagnostic clinics. Proceedings from the Human Factors and Ergonomics Society Annual Meeting. 2012.

Upper extremity musculoskeletal injuries or disorders among dental hygienists - 20123

N = 729
36% dominant hand
20.3% non-dominant hand
20.2% thumb
15.7% fingers
10.4% forearm
14.3% elbow

ANNE NUGENT GUIGNON, RDH, MPH, 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. She can be contacted at [email protected].