Ergonomic interventions for preventing musculoskeletal disorders in dental care practitioners

Background Dentistry is a profession with a high prevalence of work-related musculoskeletal disorders (WMSD) among practitioners, with symptoms often starting as early in the career as the student phase. Ergonomic interventions in physical, cognitive, and organisational domains have been suggested to prevent their occurrence, but evidence of their effects remains unclear. Objectives To assess the effect of ergonomic interventions for the prevention of work-related musculoskeletal disorders among dental care practitioners. Search methods We searched CENTRAL, MEDLINE PubMed, Embase, PsycINFO ProQuest, NIOSHTIC, NIOSHTIC-2, HSELINE, CISDOC (OSH-UPDATE), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform (ICTRP) Search Portal to August 2018, without language or date restrictions. Selection criteria We included randomised controlled trials (RCTs), quasi-RCTs, and cluster RCTs, in which participants were adults, aged 18 and older, who were engaged in the practice of dentistry. At least 75% of them had to be free from musculoskeletal pain at baseline. We only included studies that measured at least one of our primary outcomes; i.e. physician diagnosed WMSD, self-reported pain, or work functioning. Data collection and analysis Three authors independently screened and selected 20 potentially eligible references from 946 relevant references identified from the search results. Based on the full-text screening, we included two studies, excluded 16 studies, and two are awaiting classification. Four review authors independently extracted data, and two authors assessed the risk of bias. We calculated the mean difference (MD) with 95% confidence intervals (CI) for continuous outcomes and risk ratios (RR) with 95% confidence intervals for dichotomous outcomes. We assessed the quality of the evidence for each outcome using the GRADE approach. Main results We included two RCTs (212 participants), one of which was a cluster-randomised trial. Adjusting for the design effect from clustering, reduced the total sample size to 210. Both studies were carried out in dental clinics and assessed ergonomic interventions in the physical domain, one by evaluating a multi-faceted ergonomic intervention, which consisted of imparting knowledge and training about ergonomics, work station modification, training and surveying ergonomics at the work station, and a regular exercise program; the other by studying the effectiveness of two different types of instrument used for scaling in preventing WMSDs. We were unable to combine the results from the two studies because of the diversity of interventions and outcomes. Physical ergonomic interventions. Based on one study, there is very low-quality evidence that a multi-faceted intervention has no clear effect on dentists' risk of WMSD in the thighs (RR 0.57, 95% CI 0.23 to 1.42; 102 participants), or feet (RR 0.64, 95% CI 0.29 to 1.41; 102 participants) when compared to no intervention over a six-month period. Based on one study, there is low-quality evidence of no clear difference in elbow pain (MD 0.14, 95% CI 0.39 to 0.11; 110 participants), or shoulder pain (MD 0.32, 95% CI 0.75 to 0.11; 110 participants) in participants who used light weight curettes with wider handles or heavier curettes with narrow handles for scaling over a 16-week period. Cognitive ergonomic interventions. We found no studies evaluating the effectiveness of cognitive ergonomic interventions. Organisational ergonomic interventions. We found no studies evaluating the effectiveness of organisational ergonomic interventions. Authors' conclusions There is very low-quality evidence from one study showing that a multi-faceted intervention has no clear effect on dentists' risk of WMSD in the thighs or feet when compared to no intervention over a six-month period. This was a poorly conducted study with several shortcomings and errors in statistical analysis of data. There is low-quality evidence from one study showing no clear difference in elbow pain or shoulder pain in participants using light weight, wider handled curettes or heavier and narrow handled curettes for scaling over a 16-week period. We did not find any studies evaluating the effectiveness of cognitive ergonomic interventions or organisational ergonomic interventions. Our ability to draw definitive conclusions is restricted by the paucity of suitable studies available to us, and the high risk of bias of the studies that are available. This review highlights the need for well-designed, conducted, and reported RCTs, with long-term follow-up that assess prevention strategies for WMSDs among dental care practitioners.