Date Presented 4/20/2018
Upper extremity musculoskeletal injuries are common in dental hygienists. To enhance prevention, an ecologically valid observational technique for evaluating risks in dental hygiene practice is needed. This study describes a new video observation technique and reliability results.
Primary Author and Speaker: Shawn Roll
Contributing Authors: Mark E. Hardison, Nikki Colclazier
PURPOSE: The purpose of this study was to develop a video-based observational method to identify risk of musculoskeletal strain in dental hygienists. Nearly 70% of dental hygienists experience upper extremity musculoskeletal injuries (Hayes et al., 2009) because of pinch, repetitive motion, and awkward postures required to complete scaling of patient teeth (Akesson et al., 2012). Longitudinal studies have not been conducted to examine this relationship, and observational studies have used only contrived, laboratory settings. To enhance injury prevention, an ecologically valid and reliable observational technique for evaluating risks in dental hygiene practice is needed.
METHOD: This reliability study used a cross-sectional, case series design. Dental hygiene students enrolled in the second year of their academic program were recruited. No exclusion criteria were applied, provided that both student and patient gave informed consent to be recorded.
Iterative feasibility trials were used to identify the ideal number and location of cameras necessary to capture student postures and hand use while conducting dental scaling tasks. An interdisciplinary team of dental hygienists and occupational therapists collaborated to develop and validate a data collection protocol, which involved three cameras positioned in orthogonal views (lateral, front, and overhead). Position of the student relative to the patient, area of the mouth being scaled, and sitting and standing position were continuously coded using ObserverXT (Noldus, Inc., Leesburg, VA). These data were combined to identify postures sustained for >1 min, and 20 1-min video segments of sustained posture were randomly selected. Using the Rapid Upper Limb Assessment (RULA; McAtamney & Corlett, 1993) and the Revised Strain Index (RSI; Garg et al., 2017), three raters evaluated each segment multiple times in random order; raters were blinded to previous results.
Descriptive statistics were calculated. The RULA and RSI were validated between in-person and video observations. Intra- and interrater reliability were calculated using intraclass correlation coefficients (ICCs).
RESULTS: Feasibility was established through seven recording sessions, after which four videos were obtained for analysis. On average, students spent 1 hr, 45 min, completing scaling tasks per session and were primarily positioned directly to the patient’s right. On average, students used postures with mild to moderate risk (RULA average = 3.83, SD = 1.27), but many neck and trunk postures presented severe risk (i.e., >5). Average hand strain was 47.5 points (SD = 22.1), indicative of moderate strain. Interrater reliability for the RULA and RSI and intrarater reliability for the RULA were good to excellent (ICCs >.80). All intrarater reliability for the RSI was moderate (ICCs ∼.50), with variability noted in assessments of force and number of exertions.
CONCLUSION: Video-based observations are a feasible and valid method for assessing dental hygiene ergonomics. Postural assessment using the RULA is highly reliable, whereas assessment of force and exertions may require averaging across multiple views to improve rater reliability of hand strain.
IMPACT STATEMENT: Although restricted by the small sample, these data suggest that students may work in sustained harmful positions, especially for the neck and trunk, providing a target for training and intervention. Once refined, this video analysis technique can be used to evaluate physical exposures by therapists consulting with dental professionals, as a self-assessment tool for training dental hygiene students and clinicians, or in larger-sample longitudinal cohort studies that can more formally evaluate risk factors.
References
Akesson, I., Balogh, I., & Hansson, G. A. (2012). Physical workload in neck, shoulders and wrists/hands in dental hygienists during a work-day. Applied Ergonomics, 43, 803–811. https://doi.org/10.1016/j.apergo.2011.12.001
Garg, A., Moore, J. S., & Kapellusch, J. M. (2017). The Revised Strain Index: An improved upper extremity exposure assessment model. Ergonomics, 60, 912–922. https://doi.org/10.1080/00140139.2016.1237678
Hayes, M., Cockrell, D., & Smith, D. R. (2009). A systematic review of musculoskeletal disorders among dental professionals. International Journal of Dental Hygiene, 7, 159–165. https://doi.org/10.1111/j.1601-5037.2009.00395.x
McAtamney, L., & Corlett, E. N. (1993). RULA: A survey method for the investigation of work-related upper limb disorders. Applied Ergonomics, 24, 91–99. https://doi.org/10.1016/0003-6870(93)90080-S
