The three-axial gyroscope sensor detects the turning point between opening and closing phases of chewing.

Most devices measuring the kinematics of masticatory function are cumbersome to setup and not portable. Data collection would be facilitated, particularly in the elderly, if the device used for the objective measurement of mastication was easily transportable and simple to setup. Accelerometers and gyroscope sensors are lightweight and portable and may be useful alternatives. The definition of the turning point between the opening and closing phases of chewing is important for studies of associations between muscle activity and effects of perturbations. Measures of the mediolateral angle (specifically, the mandibular tilt from the lateral view) allow the detection of the turning point between the opening and closing phases. The aim was to determine whether a three-axial gyroscope sensor can detect the turning point between opening and closing phases of chewing. Fourteen asymptomatic participants chewed gum while the output was recorded from a three-axial gyroscope sensor (Seiko Epson, Japan) attached to the chin and a 6 degree-of-freedom electromagnetic jaw-tracking device (Pollhemus, USA). Bland-Altman plots were used to assess the matching of the recordings made by the three-axial gyroscope sensor and the jaw-tracking device. The turning points between the opening and closing phases of chewing matched closely when recorded by a jaw-tracking device and when using a three-axial gyroscope sensor. A three-axial gyroscope sensor can validly detect the turning point between the opening and closing phases during chewing of gum.