A study from the University of California Ergonomics Program is the first randomized control trial to show that decreasing the weight and increasing the diameter of dental tools used by dentists and hygienists may be a cost-effective way to reduce or prevent arm and shoulder pain. Up to sixty-one percent of dental professionals in the United States suffer symptoms in their right arm. Over time, ergonomic hazards can lead to reduced work hours, surgery, and disability retirement.
During the trial, dental professionals who used the light-weight tool also reported a reduction in their use of pain medication. In addition, their sleep improved. The number of nights they were awakened because of numbness in their right hand was cut in half, from two nights a week to less than one.
The study, led by David Rempel, included 110 San Francisco Bay Area dental hygienists and dentists who routinely performed scaling, root planning, or dental prophylaxis procedures. Recruits were excluded from the study if they were receiving medical care for an upper extremity disorder.
Researchers provided approximately half of study participants with a set of ergonomically designed periodontal tools with a weight of 14 grams and diameter of 11 millimeters (mm). The remainder received traditional, heavier instruments with a weight of 34 grams and a narrow diameter of 8 mm. Participants had no idea which features of the tool were being compared, therefore, they were masked to the intervention.
For five months, participants completed a weekly online questionnaire where they reported pain of the right wrist, hand, elbow, forearm, and shoulder on a scale of zero to 10. The questionnaire also assessed their use of pain medication and how many nights they were awakened due to finger numbness in the right hand.
Pain scores improved more for those who used the lighter instrument with a larger diameter. The reduction in shoulder pain was the most pronounced benefit of the ergonomic tool.
“The outcome of this population study followed the results of our prior laboratory investigations,” said Rempel. “This confirms that our laboratory-based studies can predict health outcomes in later population studies.”
Rempel, a professor of Medicine at UCSF and director of the Ergonomics Graduate Training Program at UC Berkeley, is lead author of the paper published in the October 2012 issue of the Journal of the American Dental Association, “The effect of periodontal curette handle weight and diameter on arm pain: a four month randomized control trial.”
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