Ergonomic evaluation and construction of a reference workplace in dental hygiene: a case study

In an earlier survey study, a high frequency of complaints from the neck and shoulder were found in dental hygienists employed by the National Dental Service in Jönköping, Sweden. As a consequence of these survey findings, a new in-depth study of the workplace of one Swedish dental hygienist was performed to identify critical factors causing work-related pain in the neck and shoulders. This also served as a pilot study for testing simple ergonomic methods suitable for field studies in dental hygiene.

Several workplace evaluation methods were used: time distribution study, posture targeting diagrams, biomechanical computations, serial photography, and videorecording.

All methods showed the same general picture--fixed working postures, a sparse movement pattern, work within a very limited work space, and long-standing static load on the neck and shoulder muscles.

As a result of these findings, a reference workplace was designed to provide an ergonomically desirable environment. The load was reduced by means of a specific horseshoe-shaped support for the patient chair and a special armrest for the operator chair.