The biomechanical demands of manual scaling on the shoulders & neck of dental hygienists

Abstract

The purpose of this study was to evaluate the postural and muscular demands placed on the shoulders and neck of dental hygienists when performing a simulated manual scaling task. Nineteen healthy female dental hygienists performed 30-min of simulated manual scaling on a manikin head in a laboratory setting. Surface electromyography was used to monitor muscle activity from several neck and shoulder muscles, and neck and arm elevation kinematics were evaluated using motion capture. The simulated scaling task resulted in a large range of neck and arm elevation angles and excessive low-level muscular demands in the neck extensor and scapular stabilising muscles. The physical demands varied depending on the working position of the hygienists relative to the manikin head. These findings are valuable in guiding future ergonomics interventions aimed at reducing the physical exposures of dental hygiene work.

Practitioner Summary: Given that this study evaluates the physical demands of manual scaling, a procedure that is fundamental to dental hygiene work, the findings are valuable to identify ergonomics interventions to reduce the prevalence of work-related injuries, disability and the potential for early retirement among this occupational group.

Keywords:

• Dental ergonomics
• dental hygiene
• physical demands
• neck
• shoulder

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.