Self-assessed and direct measured physical workload among dentists in public dental clinics in Sweden during a period of rationalizations

Much research has been done on interventions to reduce work-related musculoskeletal disorders (WMSDs) at the workplace. However, this problem is still a major concern in working life. The economic cost for WMSDs corresponds to between 0.5% and 2% of the gross national product in some European countries, and in 2007, 8.6% of workers in the EU had experienced work-related health problems during the previous 12 months. In Sweden, one in five of all employees have rated occurrence of WMSDs during the previous 12 months. In spite of comprehensive ergonomic improvements of workplace and tool design in dentistry the prevalence of musculoskeletal disorders in neck, upper arms and back is reported to be between 64% and 93%. The present thesis investigates if the perceived high exertion during work corresponds to actual physical exposures. Further, it is investigated if risk full physical exposures may be generated due to rationalisations. Specifically, changes in physical exposures are investigated prospectively during a period of rationalisations. Empirical data on production system performance, individual measured physical workload, and self-rated physical workload are provided. High estimates of self-rated workload were found. These high scores for perceived workload were associated with high measured muscular workload in the upper trapezius muscles. Also, negative correlations were found between low angular velocities in the head, neck and upper extremities on the one hand, and estimates for perceived workload on the other. Both measured muscular workload and mechanical exposure among dentists indicate a higher risk of developing WMSDs than in occupational groups with more varied work content. Value-Adding Work (VAW) comprised about 57% of the total working time and compared to industrial work an increase with about 20 percent units is hypothesised. Furthermore, VAW compared to non-VAW (“waste”) implies more awkward postures and especially low angular velocities interpreted as constrained postures. Consequently, when increasing the proportion of time spent in VAW due to rationalisations, work intensification is expected. However, at follow up, we did not find such work intensification. Previous research indicates that rationalisation in working life may be a key factor in the development of WMSD. The present thesis suggests that ergonomics may then be considered proactively as part of the rationalisation process