- Smart Mouthguard -
Overview
Since the Industrial Revolution in the 18th century, medical technologies have advanced with the primary goals of treating diseases and prolonging life. Today, in the era of Society 5.0, healthcare is shifting toward preventive medicine and pre-disease care, aiming to extend healthy life expectancy.
As an innovative technology to realize this goal, continuous vital sensing through in-body IoT sensors is becoming essential. The oral cavity, in particular, contains abundant health-related information such as saliva and occlusal (biting) force. Therefore, a smart mouthguard embedded with sensors is expected to serve as a continuous health barometer.
Oral Energy Harvesting from Biting Force
When equipping a mouthguard with sensors, batteries cannot be used due to the risk of accidental ingestion, making power supply a key challenge. To address this, our group is developing a thin power-generating sheet using electrets.
Electrets are special materials capable of retaining an electric field semi-permanently. When the mouthguard is bitten, the sheet is slightly compressed, converting occlusal force (mechanical energy) into electrical energy. Compared to piezoelectric elements used in floor power generation, our system achieves more than 100 times greater power output under human biting force.
Occlusal Force Sensing
The decline of oral functions such as occlusal force with aging is known as oral frailty. Progression of oral frailty increases the risk of requiring nursing care, making its early detection critically important for extending healthy life expectancy.
To address this, we also apply the above-mentioned power-generating sheet to occlusal force sensing. By analyzing the voltage generated during compression and solving for the nonlinear characteristics of compression and circuit dynamics, we can estimate the type of occlusal force being applied. We are developing three-dimensional occlusal force sensing technology capable of measuring not only compressive force but also shear forces, such as those caused by teeth grinding.
