Self-powered mouthguard-type bite force sensor with wide dynamic range

• Self-powered mouthguard-type sensor utilizing thin energy harvester. • Estimation of applied pressure from output voltage based on theoretical model. • Up to 2.5 MPa pressure can be measured by fabricated sensor. Bite force is a critical indicator of both oral and systemic health. However, traditional bite force sensors are limited by their inability to provide continuous and unrestricted measurements. In this study, we developed a wearable mouthguard-type sensor designed for continuous bite force monitoring. The sensor was fabricated by embedding a thin sensor sheet within a double-layered mouthguard. This sensor generates a voltage in response to the bite force applied to the mouthguard, eliminating the need for a battery. The bite force applied was estimated from the output voltage using a theoretical model based on the sensor’s electrical and mechanical characteristics. To achieve a sufficient dynamic range for effective bite force monitoring, we investigated three dielectric polymer materials for the sensor sheet. Because the dynamic range of the sensor is influenced by the mechanical properties of the material, we attained a dynamic range of 2.5 MPa, which is equivalent to a bite force of 1 kN in the whole dentition, by selecting an appropriate material, demonstrating promising results in vitro. With further in vivo experimental evaluation, the proposed mouthguard-type sensor shows potential for effective bite force monitoring.