Analysis of Tooth-Brushing Motion with High Precision Motion Capture

Second Report : Method to Quantitatively Evaluate the Movement of the Arm

Abstract

There are many opportunities for teaching of tooth brushing in dental clinical practice. However, an obvious index to assess the brushing motion skill of patients has not been established. We have reported that an individual's frequency during tooth brushing can provide a numerical index to assess their brushing motion skill. Tooth brushing motion is a detailed coordinated movement between the arm and oral cavity. A method is needed to objectively assess, instruct and educate about tooth brushing motion, and to clarify the evidence-based component of an individual's frequency and detailed regulation of arm movement during tooth brushing.In this study, we focused on arm motion during tooth brushing. Tooth brushing motion, performed by a dental hygienist for 15 seconds, was captured using a motion-capture system that continuously calculates the three-dimensional coordinates of an object's motion relative to the floor. The dental hygienist brushed the buccal side of the right and left upper molars. The frequency and power spectrum of joint angles of the shoulder, elbow and wrist were calculated and analyzed statistically.Study conclusions :1)All arm joints moved synchronously during brushing of both the upper right and left molars.2)Tooth brushing motion was controlled by coordinated movement of the joints of the arm. The results suggest that the shoulder and wrist regulate brushing on the right side, and the wrist does the same on left side.3)The results suggest that the elbow generates an individual's frequency through a stabilizing movement rather than through detailed control of movements on the right and left sides.