Biomechanical study of dentists' posture when using a conventional chair versus a saddle-seat chair

Objectives: This study aimed to provide information about dentists' body posture on a conventional chair vs. a saddle-seat chair while performing dental procedures. Information was obtained using inertial motion sensors. Methods: Twenty-four dentists performed a Class I cavity in the upper right and left first molars and lower right and left first molars. Nineteen dentists worked on a conventional chair (Group I), and five on a saddle-seat chair (Group II). Kinematic measurements of the whole body were registered using Xsens® MVN BIOMECH. Results: Both groups worked with a pronounced forward head position. Lateral flexion of the head was similar between groups, and head rotation was more evident in Group II. Regarding trunk position, Group II showed less forward leaning and lateral flexion than Group I. Arm elevation of both the left and right arms was more pronounced in Group I during all dental tasks. However, Group I showed better left-hand posture. Anterior rotation of the pelvis was most evident while working on the lower jaw in Group II. Conclusions: This study suggests that the saddle seat improves the working posture regarding pelvis rotation, arm elevation, and trunk flexion. Further studies should include objective measurements of the dentists' posture during dental work using different dental equipment, to understand the role of ergonomics in dentistry.