Working postures of dental students: ergonomic analysis using the Ovako Working Analysis System and Rapid Upper Limb Assessment

Abstract

Background: As dentistry is a profession that demands a manipulative precision of hand movements, musculoskeletal disorders are among the most common occupational diseases. Objectives: This study estimated the risk of musculoskeletal disorders developing in dental students using the Ovako Working Analysis System (OWAS) and Rapid Upper Limb Assessment (RULA) methods, and estimated the diagnostic agreement between the 2 methods. Methods: Students (n = 75), enrolled in the final undergraduate year at the Araraquara School of Dentistry - UNESP - - were studied. Photographs were taken of students while performing diverse clinical procedures (n = 283) using a digital camera, which were assessed using OWAS and RULA. A risk score was attributed following each procedure performed by the student. The prevalence of the risk of musculoskeletal disorders was estimated per point and for a 95% CI. To assess the agreement between the 2 methods, Kappa statistics with linear weighting were used. The level of significance adopted was 5%. Results: There was a high prevalence of the mean score for risk of musculoskeletal disorders in the dental students evaluated according to the OWAS method (p = 97.88%; 95% CI: 96.20-99.56%), and a high prevalence of the high score (p = 40.6; 95% CI: 34.9-46.4%) and extremely high risk (p = 59.4%; 95% CI: 53.6-65.1%) according to RULA method. Null agreement was verified (k = 0) in the risk diagnosis of the tested methods. Conclusion: The risk of musculoskeletal disorders in dental students estimated by the OWAS method was medium, whereas the same risk by the RULA method was extremely high. There was no diagnostic agreement between the OWAS and RULA methods.