Working position influences the biomechanical demands on the lower back during dental hygiene

Abstract

This investigation monitored the biomechanical demands on the lower back during simulated dental hygiene work. A total of 19 female, registered dental hygienists performed 30 continuous minutes of manual scaling (plaque removal) of a manikin’s teeth while seated. We monitored the working location and orientation of the dental hygienists, with respect to the manikin, along with their spine kinematics, spine extensor muscle activities and seat pressure, throughout the 30 min. A clock representation was used to express the working location. The location significantly influenced the dental hygienists’ pelvic orientation with respect to the manikin, spine posture, erector muscle activity and pressure distribution. Findings from this study suggest that the prevalence of lower back pain amongst dental hygienists may be directly related to low-level tonic activity of the spine’s extensor musculature, and the combined flexed and axially rotated spine postures.

Practitioner Summary:

Low back pain (LBP) is prevalent in dental hygienists, yet occupational demand on the low back has not been investigated. Posture, muscle activity and seat pressure were monitored. Combined spine rotation and flexion, and tonic activity of the extensor musculature may be related to LBP in dental hygienists.

Keywords:

• Spine posture
• electromyography
• lower back pain
• injury
• sitting

Acknowledgements

We would like to acknowledge the assistance of Mr Steven Tran during data collection, the in-kind rental of the dental chair from the University of Toronto Faculty of Dentistry, the support of the Canadian Dental Hygienists Association and the donation of the manikin head from Columbia Dentoform.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was supported by the Ontario Ministry of Labour [grant number 12124].