Clinical work posture for the dentist: an electromyographic study.

The results of this study suggest that lumbar support is a significant factor in reducing muscle activity of the upper and lower back for the dentist practicing sit-down dentistry. The importance of lumbar support should be emphasized in any criteria listing correct work posture for the dentist. Under the conditions of this study, stool heights did not influence muscle activity significantly, but did suggest a trend in considering problems of the lower back posture--low stool heights (90 degrees and 75 degrees) produced lower activity than a high stool height (105 degrees) if the back was supported. Therefore, in regard to muscle activity, results of this study suggest that the dental operator should sit low with the lumbar support always in contact with the lower back.