Work load, fatigue, and pause patterns in clinical dental hygiene

Area of Science:

• Occupational Health
• Ergonomics
• Biomedical Engineering

Background:

• Dental hygienists often report shoulder and neck complaints.
• These complaints are frequently attributed to prolonged, low-level static muscle load.
• Understanding the specific muscle load is crucial for prevention.

Purpose of the Study:

• To continuously record myoelectric signals from dental hygienists' shoulder muscles.
• To assess the static load experienced during work tasks.
• To investigate the relationship between muscle activity and potential fatigue.

Main Methods:

• Myoelectric signals were recorded from the trapezius muscle of 10 Swedish dental hygienists.
• A portable system was used for on-line collection and processing of electromyography (EMG) data.
• Measurements were referenced to resting and standard contraction levels (0.5 kg hand load).

Main Results:

• The trapezius muscle exhibited static loads ranging from 50% to 100% of the reference contraction.
• Median static load for the group was 57% of the reference level.
• While group EMG analysis showed little significant fatigue, individual analysis revealed localized muscle fatigue linked to specific tasks, with frequent short pauses and a lack of longer recovery periods.

Conclusions:

• Individual dental hygienists demonstrated significant muscle fatigue, potentially contributing to work-related shoulder myalgias.
• Further research into muscle activity patterns and specific dental hygiene tasks is recommended.
• Improved work designs and task patterns could mitigate risks for dental hygienists.