Work-related musculoskeletal disorders (WMSDs) are now recognized as a serious problem for dental care workers. Dentists and dental hygienists have been diagnosed with conditions consistent with (WMSDs) including carpal tunnel syndrome and other nerve entrapment disorders, medial and lateral epicondylitis, wrist tenosynovitis and tendonitis, and cervical spine problems. Studies done in the 1990’s in Europe and the United States found that the majority of dental care workers experienced symptoms consistent with WMSDs including neck pain, numbness and tingling in the hands and fingers, and low back pain. The many hand-intensive procedures dental care workers perform, coupled with long periods of seated or stooped posture, forward neck flexion, and static loading are a significant concern to the profession.
Possible control measures
- Alternate postures and the muscle groups being used. Varying periods between sitting and standing is preferred. This will provide more postural variety for the spine and helps to reduce static muscle fatigue. Although many of the tasks performed require repetitive movements, alternating between using the larger muscles of the arms and shoulders, and then the smaller muscles of the hands and wrists, is recommended.
- Use of automatic or ultrasonic instruments and tools whenever feasible. Tools requiring continuous operation should have foot-activated controls to relieve upper extremities from constant applied force.
- Adjust the patient’s chair so that trunk and neck flexion are minimized for the dentist or hygienist.
- Keep all frequently used instruments within a range of about 20 inches to maintain a neutral work envelope.
- When replacing dental instruments, consider those with larger diameter and/or curved handles.
- Rather than relying on the traditional stool, consider using a saddle chair. When correctly used, these chairs help the user maintain proper spinal alignment, protecting the low back to a large degree from potential injury. Mobility, for accessing x-ray’s or equipment, is also greatly increased. Since a saddle chair puts the user in a semi-standing posture, it is important to adjust the patient’s chair to an appropriate position so that the dentist or hygienist remains in a neutral plane to the patient, allowing for better interaction and less strain on the body.
- Patient scheduling can help decrease exposure to risk factors. A dental hygienist is exposed to more repetitive wrist movements and greater applied forces when treating patients with heavy calculus deposits. If possible, patients with a history of heavy calculus buildup should be alternated with those who have less. Patients with heavier deposits can also be encouraged to have more frequent cleanings to lessen the severity of exposure for each treatment. Similarly, the dentist’s schedule can be adjusted to disperse work-intensive patients. Those patients with crown and bridge work can be alternated between those with shorter, simpler procedures.
Dental Hygiene and Ergonomics is an excellent series of five short videos developed by the California Department of Public Health designed to help workers in this field become more aware of the risk factors they are exposed to.