Musculoskeletal Disorder Risk Assessment in Dental Hygienists
Nearly 70% of dental hygienists report experiencing discomfort in their forearms/wrists/hands, primarily due to the use of dental scaling instruments. Dental scaling requires sustained pinching and repetitive movements that place high load on the forearm and hand muscles. This high muscle load, combined with pinching and non-neutral wrist positions, approximately doubles the risk of developing hand and median nerve pathology due to strain on the tendons and compression of the median nerve. Scaling of more than four hours per day has been directly associated with pathology.
Dental hygiene students have an elevated risk of musculoskeletal injury due to intensive exposure to scaling during their educational training. We have documented a significant increase in subjective reports of discomfort in the hand, wrist, and fingers of these students, with the prevalence of students with discomfort doubling to tripling across their two-year training program. Up to 60% of individuals report having discomfort at the end of their training. To enhance education, develop preventive training, and address work-related musculoskeletal disorders in dental hygienists, it is necessary to better understand the link between exposure and pathology development.
Overall, the problem of musculoskeletal injury within the practice of Dental Hygiene is a multifaceted issue. In addition to adopting awkward trunk and neck postures for long hours due to patient positioning, dental hygienists are also required to apply significant hand forces during removal of plaque and calculus from patient’s teeth. In an effort to mitigate these issues, we are utilizing a synchronized three-view video capture system to monitor dental hygienists during clinical practice.
These videos are being used in the following assessment projects:
- Task Analysis of Dental Hygiene Students: We are investigating the duration, frequency, and sequencing of various dental hygiene activities and instrumentation tasks conducted by dental hygiene students within a clinical setting. We aim to not only describe the activity of dental hygiene students, but to provide nuances of the various positions and relative organization of the workspace, which could help to identify targeted evaluations of postures and other health risks. These data will provide insight into key areas for evaluation and training as a foundational step in reducing injury potential in dental hygienists.
- Postural Assessment in Dental Hygiene Students: The prevalence of low back pain has been reported to be as high as 68% in dental hygienists and neck/shoulder pain as high as 34%. Our team is applying the Rapid Upper Limb Assessment (RULA) tool as a means of investigating musculoskeletal injury potential for dental hygienists during various instrumentation tasks they perform throughout a single patient visit. We are specifically interested in the relationship of postures to various tasks and relative positioning of the hygienist student to the patient. We aim to not only describe postures and identify key areas of highest risk, but also to compare the postures adopted among students with and without complaints of musculoskeletal discomfort.
- Hand Strain in Dental Hygiene Students: In a recent study, 75% of dental hygienists surveyed reported having hand problems while 56% exhibited direct symptoms of carpal tunnel syndrome (CTS). We are investigating the amount of incident and overall strain within the hand that dental hygiene students are exposed to using the Revised Strain Index (RSI). We aim to evaluate individual and cumulative strain, and will utilize these data to examine the relationship of strain exposure to the development of symptoms and other disorders.
- Ergonomic Training and Self-Monitoring in Dental Hygiene Students: Given the prevalence of musculoskeletal injuries in dental hygienists, the development of a standardized ergonomic assessment tool that is directly related to dental hygiene practice is needed. Our team is evaluating the validity and reliability of a new assessment, the Movement Strategies and Alignment Tool (MSAT), that would be useful as an adjunct to ergonomics education.
Sonographic tissue morphology in early stage work-related pathology
National Institute for Occupational Safety and Health / Centers for Disease Control
R01-OH010665 (PI: Roll)
Total Funding: $2,324,186
Funding Period: 9/30/15 – 9/29/19
Validity and reliability of ergonomic assessment tools used in dental hygiene practice
USC Office of Provost
Undergraduate Provost’s Fellow: Samanatha Randolph
Total Funding: $1,000
Funding Period: 10/1/18 – 11/30/18
Identifying Risk of Musculoskeletal Injury in Dental Hygiene Practice
USC Office of Undergraduate Programs – Undergraduate Research Associates Program
Total Funding: $4,500
Funding Period: 8/15/17 – 5/15/18
Roll, S. C., Tung, K. D., Chang, H., Sehremelis, T. A., Fukumura, Y. E., Randolph, S., & Forrest, J. L. (2019). Prevention and rehabilitation of musculoskeletal disorders in oral health care professionals: A systematic review. The Journal of the American Dental Association, 150(6), 489-502. https://doi.org/10.1016/j.adaj.2019.01.031 Show abstract
Background. The authors’ objective in this systematic review was to describe the evidence for preventive and rehabilitative interventions for musculoskeletal disorders in oral health care.
Types of Studies Reviewed. The authors conducted systematic search, screening, and eligibility processes to identify experimental, quasiexperimental, observational, and survey research studies in which the investigators either directly evaluated or predicted the effects of preventive or rehabilitative interventions on the reduction of musculoskeletal symptoms in oral health care professionals.
Results. The authors identified and screened 3,571 unique abstracts, assessed 256 full-text articles for eligibility, and included 34 articles in the review. Investigators in 17 experimental studies described the results of preventive or rehabilitation interventions and in 17 survey research studies predicted or correlated preventive or protective techniques to a reduction in musculoskeletal symptoms. The primary techniques evaluated in the studies included equipment modification, ergonomic training, and physical exercise.
Conclusions and Practical Implications. The evidence suggests that magnification loupes and indirect-vision techniques have a positive effect on the reduction of musculoskeletal symptoms. In terms of evaluating intervention efficacy, other techniques have mixed evidence or are limited by low-level study design.
Keywords. Ergonomics; injury prevention; musculoskeletal disorders; dentists; dental hygienists
Tung, K. D., Fukumura, Y. E., Baker, N. A., Forrest, J. L., & Roll, S. C. (2019). Identifying an optimal sampling method to estimate postural risk in a dynamic work task. Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 63(1), 1028-1033. https://doi.org/10.1177/1071181319631180 Show abstract
Introduction. The Rapid Upper Limb Assessment (RULA) is an ergonomic assessment tool used to screen for risk of musculoskeletal injury due to working posture. The RULA is traditionally applied once during a work task to approximate overall risk. No method exists for estimating a RULA score for work requiring frequent shifts in posture across an extended period of time.
Purpose. The goal of this study was to identify an optimal sampling method for applying the RULA across a long time-period that accurately represents overall risk.
Methods. Four right-handed female dental hygiene students were video recorded from three angles while performing hand scaling during patient clinic visits (88.97 minutes on average). RULA was continuously scored across the entire session, updating the score when a significant postural shift lasting for more than 15 seconds occurred. A time-weighted average (TWA) RULA score was calculated. Three sampling methods were evaluated: equivalent interval samples, random samples, and random samples selection weighted within “clock positions.” Each method was compared to the TWA using a paired samples t-test and percent difference.
Results. TWA RULA across the four students ranged from 3.4 to 4.3. Preliminary sampling averages using 10 samples were all within 0.2 of the TWA. Further iterations evaluating various sample sizes is ongoing.
Discussion. Preliminary results suggest that all three sampling methods provide a reasonably accurate approximation of the TWA score at the sampling rate tested. Future iterations of this analysis will be continued to identify the minimum required sampling rate to meet our TWA criterion.
Tung K, Baker NA, Fukumura Y, Forrest JL, Roll SC. Identifying an optimal sampling method to estimate postural risk. Paper presentation at: Human Factors and Ergonomics Society Annual Meeting, 2019; Seattle, WA
Tung K, Baker NA, Fukumura Y, Forrest JL, Roll SC. Identifying an optimal sampling method to estimate postural risk. Poster presentation at: USC Ostrow School of Dentistry Research Day, 2019; Los Angeles, CA.
Forrest JL, Mack WJ, Roll SC. Factors associated with the development of hand discomfort in dental hygiene students. Poster presentation at: International Symposium on Dental Hygiene, 2019; Brisbane, Australia
Roll SC, Forrest JL. Implementation of ergonomic, observational techniques that empower dental hygiene educators, practitioners, and students to reduce the risk of work-related injuries. Workshop presentation at: International Symposium on Dental Hygiene, 2019; Brisbane, Australia
Roll SC, Forrest JL, Mack WJ. Differential effects of work-related task training on upper extremity health in occupational therapy and dental hygiene students. Poster presentation at: 97th Annual Conference of the American Occupational Therapy Association, 2019; New Orleans, LA
Colclazier, N. L., Sumi, J. Y., Forrest, J. L., & Roll, S. C. (2017). Developing an observational method for assessing dental hygienists’ injury risk. Poster presentation at USC Ostrow School of Dentistry Research Day, Los Angeles, CA.
Melrose, D., Wilkins, M. A., Forrest, J. L., & Roll, S. C. (2017). Identifying risk of upper extremity injuries in dental hygiene professionals. Poster presentation at USC Ostrow School of Dentistry Research Day, Los Angeles, CA.
Colclazier, N. L., Sumi, J. Y., Forrest, J. L., & Roll, S. C. (2017). An observational method for injury risk assessment of dental hygienists. Poster presentation at 94th Annual Conference of the American Dental Hygienists’ Association, Jacksonville, FL.
Hardison, M. E., Colclazier, N., & Roll, S. C. (2017). Risk for musculoskeletal strain among dental hygiene students: Video analysis protocol and pilot testing. Poster presentation at 6th Annual Occupational Therapy Summit of Scholars, Boston, MA.
Melrose, M. D., Wilkins, K., Forrest, J. L., & Roll, S. C. (2017). Identifying risk of hand injuries in dental hygienists: A longitudinal cohort study. Poster presentation at American Dental Educators Association Allied Program Directors’ Conference, Baltimore, MD.