Hygiene instrumentation, hand health, and ergonomic harmony

Editor's note: Originally published November 1, 2020. Updated April 2022

After practicing clinical dental hygiene for 14 years, I considered myself very fortunate that, despite some occasional work-related aches and pains, I never experienced any serious symptoms of musculoskeletal disorders (MSDs), particularly with my hands and wrists. Unbeknownst to me, the years of “making do” with many instruments that were either not ergonomically designed or past their prime were slowly taking an irreversible toll on my hand health. 

Further adding to this was not having instruments that held their sharpness longer, and reserving sharpening for when I had time, which was not frequently enough to protect my hands. I was successful with removal, and was not experiencing any issues, so I incorrectly assumed that I would continue to remain healthy.

Read more:

• Preserving your hands in dental hygiene
• You've heard of carpal tunnel. How about trigger finger?

Although this damage was likely years in the making, the pain came on suddenly and relentlessly, affecting me physically, emotionally, and financially. My injury not only had an effect on my career, but also on my life outside of work as I dealt with chronic pain. As a clinical instructor, a role I held for many years, I had expanded knowledge of instrumentation but had no idea how a few compromises would so greatly impact my clinical career and my life. 

Some statistics on pain

Unfortunately, I am sure that many reading this article have experienced hand pain related to practice. Research has indicated that the hand and wrist are the most prevalent regions for dental hygienists to experience MSDs.¹ A study published in the Journal of Dental Hygiene in 2001 reported that the highest rate of diseases of the hand and wrist in the field of dentistry were among dental hygienists. Of 5,000 Army dental professionals surveyed, 75% of the dental hygienists reported hand problems. Those who spent more than 50% of their time working with patients with heavy deposits were 2.3 times more likely, and those who had been practicing greater than 10 years were 1.9 times more likely, to develop hand problems.² 

A 2016 study similarly reported that when compared to other dental professionals, dental hygienists may be at an increased risk of MSDs based on repetitive strain and cumulative trauma that can result from the nature of our work. The one-year prevalence rate of MSDs among dental hygienists ranged from 60% to 96%, with pain reported in the neck, shoulder, wrist, hand, and back. Without proper knowledge, preventive and/or coping methods, hygienists may be forced to endure daily pain. Allowing injuries to progress without intervention may force some to leave clinical practice.³

What can we do?

What does this mean for us, particularly with the increased use of hand scaling over recent months as we navigate practicing within the constraints of a novel virus? It means that we have to stay informed about best practices, equipment, and products designed to protect our health and the longevity of our clinical careers. Sparked by my own injury, I have researched, written, and presented material to help colleagues identify potential problems proactively, while I share solutions and strategies to protect the hand health of my peers. I am always interested in exploring ideas and products. That, combined with a decade and a half of clinical teaching, taught me that not all instruments are created equally. 

The problem with pinch force

With regard to hand injuries, an important risk factor in dental practice is forceful pinching between the thumb and index finger, which occurs during dental scaling. “The use of unnecessary force in a pinch grip is the greatest contributing risk factor in the development of injury among dental hygienists.”⁴ My own hand issues can be attributed to increased pinch force that can occur with instruments that are too thin, those that are not properly balanced, those that are dull, having a weak fulcrum, improper finger position/hyperextended joints, and the design of the instrument handle. Ergonomic instrument design can greatly reduce the need for excessive pinch force, thereby aiding in the protection of hand health and may reduce the prevalence of MSDs among dental practitioners.^1,5

Harmony Ergonomic Scalers and Curettes

Recently, I had the opportunity to experience the new line of Harmony ergonomic scalers and curettes from Hu-Friedy, now a member of HuFriedyGroup, which are designed using TrueFit Technology. When evaluating an instrument, I look for factors that will allow me to comfortably reduce my pinch force and promote efficiency to decrease the pressure and number of strokes to get the job done. 

Balance

One of the first things I look for in any new instrument is balance. Balance refers to the working ends being centered along the long access of the handle. Balanced instruments allow the finger pressure to be transferred more effectively to the working end. This results in a decrease in the pinch strength necessary, thereby reducing muscle stress and the potential for injury.⁵ The precision manufacturing process used for Harmony produces perfectly balanced handles, which may reduce fatigue.^1,2,6,7 

Handle shape

What I noticed immediately when I grasped the instruments was the way the ergonomically designed handle rested easily, naturally, and comfortably in my modified pen grasp. The wide, rounded and tapered shape of the Harmony Scaler handle allowed for easy adaptation of my grasp without compromise. 

The benefits of the wide handle with a tapered shape have been supported by evidence. It has been shown that instrument handles with a round and tapered shape and a diameter of at least 10 mm require less force while those that are thinner are associated with cramping.^8-10 A 2007 piece published in Applied Ergonomics found that tapered handles reduced the average median pinch force by 11% compared to nontapered handles.⁹ “Tapered shaped handles can allow for improved coupling of the finger pads to the handle during the high force pulling motions required for scaling.”⁹ I could observe this directly when practicing with the Harmony instruments.

The Harmony Scaler handle shape also allowed my index finger and thumb to rest comfortably on the handle with a space between them, both when at rest and when activating and rolling the instrument. This optimized shape of the Harmony Scaler handle is designed to promote a secure grasp that allows for ease of finger movement as the instrument is navigated around the tooth. 

When the index finger and thumb are too close—or worse, overlapping—it makes rolling the instrument more difficult, which can affect proper adaptation. This can decrease optimal engagement of the cutting edge to the tooth. When a compromise is made here, fingers often split and/or additional force and strokes are needed for effective removal. This increases the likelihood of pain, cramping, and cumulative damage to the hand. 

Additionally, the smooth transition from the handle to the functional shank allows for easy adaption to all hand sizes, as evidenced when I had three colleagues also try the instruments. Despite the differences in our hand sizes and preferences, our reactions were very similar in that we found the Harmony Scaler was noticeably more comfortable to grasp and maneuver.

Knurling pattern

Another obvious feature I noticed in the handle design was the unusual knurling pattern. Knurling is the texture of the instrument handle. The way I often describe this to students is by using an analogy. Compare the feeling of walking on a marble floor with smooth bottomed shoes to that of walking across the same floor with running shoes. Clearly the running shoes provide better traction and stability. 

Now picture walking across the same floor with hiking boots. The boots will provide the best traction and stability as the bottoms are the most textured. The same can be said for knurling patterns on instrument handles. The more ergonomic the texture, the greater the friction of the fingers on the handle, thereby decreasing the pressure/pinch force needed to securely hold the instrument without slipping, even in a wet environment.¹¹

The decrease in pinch force that is created with prominent knurling, as evidenced on the Harmony Scaler handle, can alleviate hand fatigue and reduce injury risk due to repetitive motion.^1,2,6,7 The recessed double-helix knurling pattern of the Harmony Scaler handle has been the most textured I have personally experienced to date. Studies show the optimized shape and double-helix patterned grip of the Harmony Scaler handle reduces pinch force up to 65% compared to other leading designs.¹² Further, I noticed that the silicone grip between the handle and functional shank is longer than others I have used, which made a noticeable difference in the ability to comfortably and securely grasp the instrument with less pressure.¹² 

EverEdge 2.0 Working Ends

When adapting the Harmony Scaler designed with TrueFit Technology to the tooth, I could feel the cutting edge easily and securely engage with the tooth surface with no slipping. The result was an effective removal stroke without the need for excessive pinch force or lateral pressure. 

The design incorporates EverEdge 2.0 Technology into the working ends. This technology yields a blade that is 72% sharper than the next leading competitor and is a result of the combination of the properties of the metals, heat treatment, and cryogenics used in the manufacturing process.¹² 

Working with dull instruments has been shown to force the wrist out of a neutral position, which is a risk factor for developing MSDs. Additionally, the force needed to work with a dull instrument increases the likelihood of pain and cumulative trauma to the hand and increases the risk of losing control of the stroke, which can result in injury to the patient and/or clinician.

Lastly, dull cutting edges can burnish calculus. This can make removal more time consuming and difficult, impacting both the comfort level of the patient and the clinician.⁵

EverEdge 2.0 Working Ends are not only sharper but stay sharper longer. This can result in a less frequent need for sharpening, an increase in patient and clinician comfort, a decrease in the hand fatigue and injury that can be caused by the use of dull instruments, and in instruments that can last longer before needing to be replaced.¹²

Combined benefits

The features of the Harmony Scaler handle design combined with the EverEdge 2.0 sharpness of the cutting edge work in perfect “harmony” together to decrease lateral pressure against the tooth, decrease pinch force against the handle, promote a more ergonomic grasp, and allow clinicians to effectively and efficiently remove calculus. Less pressure is needed to do the same amount of work. According to the results of over 2.8 million data points collected, the Harmony Ergonomic Scalers and Curettes can decrease pressure applied to the tooth by up to 37% compared to other leading scaler handle designs.¹² Further, the design considerations that allow for decreased pressure against the tooth when scaling not only positively impact clinician time, comfort, and hand health, but patient comfort as well.⁵ 

Choices

Lastly, the Harmony Scaler and Curette handles come in a wide variety of tip designs to match clinicians’ preferences and to customize the instruments to the tasks at hand. For example, there are universals, area-specific curettes, and sickle scalers. The handles are available in more than 30 different working end designs. Additionally, there is a rigid shank option for the 11/12 and 13/14 Graceys. A rigid shank has less flexion in the instrument and is excellent to have when faced with heavier or more stubborn deposits, particularly during this time where more hand scaling may be occurring in an effort to reduce aerosol-generating procedures. 

Conclusion

As a long-term clinical instructor and a hygienist with a passion for sharing information to help protect the hand health of my peers, I can confidently say that I am impressed with the Harmony Scalers and Curettes; they checked all the boxes of my “must haves” with regard to evidence, comfort, quality, efficiency, and ergonomic considerations. 

If you are finding yourself in a situation where you are experiencing hand pain and/or you are considering if your instruments and work habits are in line with keeping yourself healthy over the long term, I encourage you to learn more and align yourself with products that will support your hand health. 

As I think back on all that I have experienced since developing an MSD of my dominant hand, I regret being less proactive and allowing myself to make compromises that ultimately limited my ability to practice. Remember that MSDs are cumulative and that you may not feel the damage today that could be career limiting tomorrow. 

Prevention is more successful than disease management, so it is critical that we arm ourselves with information, work habits, and equipment that can protect us over the long term of a career that can be so demanding on our bodies. Following through on the information we learn can promote healthier outcomes that can allow us to practice our profession with increased comfort, less work-related disease, and less interruption to income. Knowledge can also empower us to confidently ask for what we need and/or secure it ourselves. Put your future in good hands—your own.  

Editor’s note: This article is sponsored by HuFriedyGroup. Content has been reviewed for editorial integrity per RDH guidelines. For more information on our editorial standards, see rdhmag.com/page/submission-guidelines.

References

1. Hayes M, Cockrell D, Smith DR. A systematic review of musculoskeletal disorders among dental professionals. Int J Dent Hyg. 2009;7(3):159-65. doi:10.1111/j.1601-5037.2009.00395.x. PMID: 19659711. 
2. Lalumandier JA, McPhee SD. Prevalence and risk factors of hand problems and carpal tunnel syndrome among dental hygienists. J Dent Hyg. 2001;75(2):130-4.
3. Johnson CR, Kanji Z. The impact of occupation-related musculoskeletal disorders on dental hygienists. Can J Dent Hyg. 2016;50:72-79.
4. Sanders MJ, Turcotte CA. Ergonomic strategies for dental professionals. Work. 1997;8(1):55-72. doi:10.3233/WOR-1997-8107.
5. Gehrig JS, Sroda R, Saccuzzo D. Fundamentals of Periodontal Instrumentation & Advanced Root Instrumentation. 8th ed. Wolters Kluwer; 2019. 
6. Rempel D, Lee DL, Dawson K, Loomer P. The effects of periodontal curette handle weight and diameter on arm pain: a four-month randomized controlled trial. J Am Dent Assoc. 2012 Oct;143(10):1105-13. doi:10.14219/jada.archive.2012.0041. 
7. Mulimani P, Hoe VC, Hayes MJ, Idiculla JJ, Abas AB, Karanth L. Ergonomic interventions for preventing musculoskeletal disorders in dental care practitioners. Cochrane Database Syst Rev. 2018;10(10):CD011261. doi:10.1002/14651858.CD011261.pub2. 
8. Dong H, Barr A, Loomer, P, Laroche C, Young E, Rempel D. The effects of periodontal instrument handle design on hand muscle load and pinch force. J Am Dent Assoc. 2006; 137(8):1123-1130.
9. Dong H, Loomer, P, Barr A, Laroche C, Young E, Rempel D. The effect of tool handle shape on hand muscle load and pinch force in a simulated dental scaling task. Appl Ergon. 2007; 38(5);525-531.
10. Simmer-Beck M, Branson BG. An evidence-based review of ergonomic features of dental hygiene instruments. Work. 2010;35(4):477-85. doi:10.3233/WOR-2010-0984. 
11. Laroche C, Barr A, Dong H, Rempel D. Effect of dental tool surface texture and material on static friction with a wet gloved fingertip. J Biomech. 2007;40(3):697-701. doi:10.1016/j.jbiomech.2006.01.018. 
12. HuFriedyGroup data on file. Available upon request.