Measuring system for lip movements using two video trackers

Movements of soft tissues surrounding the oral cavity, especially lips and cheeks, have a strong influence on mastication and phonetics. They also influence the relationship between a denture and its oral environment. The purpose of this study was to develop a three-dimensional measuring system for soft tissue movement. This system consisted of two video trackers placed stereographically and a computer. In addition, one video tracker was connected for measuring mandibular movements. The accuracy of this system was evaluated using computerized XYZ pulse stage. The resolution of this system was 0.10 x 0.10 x 0.10 mm, when the measurement was carried out in the area of the 24.0 (X) x 20.0 (Y) x 20.0 (Z) mm with a working distance of 500 mm and a frequency of 120 Hz. In the present study, the lip movements of a dentulous subject with mandibular movements during chewing peanuts were analysed using this system. The new system demonstrated its value for analysing soft tissue movement.