en dentists were sudied to determine the effects of work posture on their muscles and circulatory system. Each dentist prepared four teeth in two different work postures, while being measured for systolic and diastolic arterial pressure, heart rate, and muscular electrical activity. Results indicated that muscular and circulatory stress was reduced when the dentists worked at the 12-o 'clock position with the mannikin positioned horizontally in front of them.