Orthodontic Force and Moment Sensing Device: Influence of Deflection of Wire and Tooth’s Orientation

Abstract

The purpose of this study is quantitative evaluation of orthodontic treatment force and moment when rotating teeth around two different axes. There is few quantitative measurements of force and moment applied to teeth during treatment. Therefore, even though the dentist performs the same way of attachment of orthodontic instrument, the movement of the teeth differ based on the dentist’s treatment skill. The measurement of the orthodontic treatment force and moment is quit important, few devices can measure the force and moment. We have developed the force and moment sensing device. The device measured 3-axis forces and 3-axis moments applied to pseudo teeth model with real orthodontic instrument. The moment applied to the tooth when the bracket attached to the tooth was rotated -20 to 20 degrees around two different axes was measured. Two moments should theoretically be the same value for each angle in different axes. However, the results of measurement demonstrate that moment is different for each axis. The moment applied to the teeth varies depending on the direction of tooth rotation. The experimental results suggest that the dentist needs to consider details: the small difference of the rotation and position, and wire attachment skill.