Yoko Ellie Fukumura

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

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.