The effects of finger rest positions on hand muscle load and pinch force in simulated dental hygiene work.

One of the techniques taught in dental and dental hygiene programs is to use finger rests to stabilize the instrument while performing dental scaling or other types of dental work. It is believed that finger rests may also reduce muscle stress and prevent injury due to muscle fatigue. In this study the effects of three different finger rest positions on hand muscle activity and thumb pinch force were compared. Twelve predental students performed simulated dental scaling tasks on a manikin using three different finger rest positions: 1) no finger rest, 2) one finger rest, and 3) two finger rests. Muscle activity and thumb pinch force were measured by surface electromyography and a pressure sensor, respectively. Using two finger rests was always associated with reduced thumb pinch force and muscle activity, as compared to not using any finger rests (p<0.05), while using one finger rest reduced thumb pinch force and muscle activity in most cases. Hence, using finger rests plays an important role in reducing the muscle load of the hand in students performing simulated dental hygiene work. It is concluded that dental and dental hygiene students may benefit from instructions for using finger rests at an early stage of their clinical training. Including biomechanical and ergonomic principles in dental and dental hygiene curricula will raise awareness of ergonomics among dental practitioners and help them incorporate these principles into daily practice.