Ergonomic interventions to prevent musculoskeletal disorders among dental care practitioners

What is the aim of this review?

Dental care providers are more prone to injuries and disorders of the bones, muscles, and joints, which are known as musculoskeletal disorders (MSDs), due to the physically and mentally stressful nature of their work. Various measures or solutions have been suggested to prevent work-related MSDs (WMSDs). These are known as ergonomic interventions, which means harmonising things with which people interact, in order to meet people's needs, abilities, and limitations. Ergonomic interventions fall under physical, cognitive (mental), or organisational domains. The aim of this Cochrane Review was to find out if any of these ergonomic interventions were effective in preventing WMSDs among dental care practitioners. We collected and analysed all relevant studies to answer this question. We found two relevant studies.

Key messages

There is very low-quality evidence from one study, that a comprehensive ergonomics intervention, consisting of training, work station modification, and a regular exercise program has no effect on dentists' risk of WMSDs in the thighs or feet, over a period of six months. There is low-quality evidence from one study that changing the tools used for scraping off dental plaque has no clear effect on dentists' elbow pain or shoulder pain over a four-month period. Both included studies have several shortcomings, and did not follow-up with participants for a sufficiently long period of time. We found no studies that evaluated the effectiveness of cognitive or organisational ergonomics interventions. We need better studies to evaluate the effectiveness of ergonomic interventions in dental care practitioners. It is very likely that including the results of new studies will change the conclusions of this review.

What was studied in the review?

Dental practitioners are highly susceptible to occupational hazards like MSDs, which have been attributed to deteriorating quality of life, burnout, and poor health, which often result in some practitioners quitting the profession. It has been suggested that introducing ergonomic interventions, by making improvements in working style, instruments used, dental office designs, physical activity, work posture, mental stress levels, appointment scheduling, or work environment may help to prevent WMSDs. Our review evaluated the effectiveness of all of these interventions in preventing WMSDs among those who practiced dentistry, be it dentists, dental hygienists, dental auxiliaries, dental nurses, or dental students. We assessed how well these measures prevented the occurrence of new WMSDs, not how they reduced the severity, or how they eliminated WMSDs that already existed. We evaluated the effectiveness of ergonomic interventions on the number of physician-diagnosed WMSDs, self-reported pain, or work ability.

What are the main results of the review?

We found two studies, involving 212 participants, that were conducted in dental practices or clinics in Iran and the United States. Both studies assessed physical ergonomic interventions. One study assessed a comprehensive ergonomics intervention, consisting of training, work station modification, and a regular exercise program, and the other study assessed two different types of instruments used for carrying out a dental procedure. The first study found that the comprehensive ergonomics intervention did not reduce musculoskeletal pain in the thighs or feet. The second study found that people using the two different kinds of tools for scraping off dental plaque had similar levels of elbow and shoulder pain. These studies had shortcomings, like poor methodology and short follow-up times, hence we could not draw any definitive conclusions based on their findings.

We found no studies that assessed the effectiveness of cognitive or organisational ergonomics interventions. We need studies that are designed, conducted, and reported better to evaluate the effects of physical, cognitive, and organisational ergonomics interventions.

How up to date is this review?

We searched for studies published up to August 2018.

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.

Read the full abstract...
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 strategy: 

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.

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