Influencing factors and occurrence patterns of work-related musculoskeletal diseases in dentists

Background Work-related musculoskeletal disorders (WMSDs) are an important cause of disability adjusted life years in China. Dentists are prone to WMSDs due to their work characteristics, which requires more attention.

Objective This study is designed to investigate the prevalence of WMSDs in dentists, analyze the relationship between the occurrence of WMSDs and adverse ergonomic factors, and explore the possible occurrence patterns of WMSDs.

Methods A self-administered musculoskeletal disease questionnaire was used to investigate the dentists nationwide from April 15 to 22, 2020. The survey included the general information of dentists, the prevalence of WMSDs affecting different body parts, and adverse ergonomic factors. Logistic regression was used to analyze the possible influencing factors of WMSDs, and latent class analysis (LCA) was used to describe possible WMSDs occurrence patterns.

Results A total of 614 valid questionnaires were received. In the past 12 months, the total prevalence rate of WMSDs was 82.4%. The prevalence rates of WMSDs in neck, low back, shoulder, and upper back were 75.2%, 50.8%, 49.7%, and 46.4%, respectively. The multiple logistic regression analysis results showed that "fair" and "bad" posture evaluation and head bent for a long time increased the risk of neck WMSDs (OR=2.383, 11.454, 3.351, P < 0.01), while "excellent" lighting in patient's mouth reduced the risk (OR=0.373, P < 0.01). The risk of low back WMSDs was increased by "fair" and "bad" posture evaluation and keeping same lumbar posture (OR=2.484, 3.310, 2.887, P < 0.01), while the risk was decreased by "excellent" lighting in the patient's mouth (OR=0.500) and seat lumbar support (OR=0.627) (P < 0.05). Compared with 1-5 years of working age, the risk of shoulder WMSDs was 1.748 times higher (OR=1.748, P < 0.05) for dentists with 6-10 years of working age. Head tilted for a long time (OR=1.862) and elbow elevated for a long time (OR=1.460) were also risk factors for shoulder WMSDs (P < 0.05). Compared with men, the risk of upper back WMSDs in women was 1.460 times higher (OR=1.460, P < 0.05). The risk of upper back WMSDs was 2.068 times and 2.225 times higher (OR=2.068, 2.225, P < 0.05) for dentists with 11-15 years and >15 years of working age compared with those with 1-5 years of working age. The prevalence of WMSDs in different body parts of dentists was classified into five classes by LCA: neck, shoulder, low back, and upper back pain class; minor pain class; neck, shoulder, low back, upper back, wrist, hand, hip, leg pain class; only low back pain class; and neck, shoulder, low back, wrist, and hand pain class. The potential category probabilities of the five classes were 0.564, 0.199, 0.119, 0.077, and 0.042, respectively. Keeping same lumbar posture and "excellent" lighting in patient's mouth were associated with WMSDs in neck, low back, shoulder, and upper back at the same time, with ORs (95% CIs) of 3.220 (1.232-8.414) and 0.410 (0.175-0.960), respectively.

Conclusion The prevalence of WMSDs in selected dentists is high. Comprehensive measures should be taken to avoid adverse ergonomic postures and reduce the incidence of WMSDs among dentists.