Accelerometry-Enhanced Magnetic Sensor for Intra-Oral Continuous Jaw Motion Tracking.

Area of Science:

• Biomedical Engineering
• Biomechanics
• Sensor Technology

Background:

• Current jaw motion tracking methods are cumbersome, limited to short durations, and unsuitable for continuous monitoring like in bruxism evaluation.
• Existing electromyography (EMG)-based devices and sensor-enhanced occlusal splints lack detailed kinematic and trajectory data.
• There is a need for a non-restrictive, long-term solution for tracking jaw movement and associated activities.

Purpose of the Study:

• To explore the feasibility of using a permanent magnet and a 3-axial magnetometer for tracking the spatial position of the mandible relative to the maxilla.
• To develop and validate an algorithm for determining sensor coordinates from magnetic field data.
• To assess the system's capability for simultaneous jaw position tracking and teeth impact detection.

Main Methods:

• Development of an algorithm to calculate sensor coordinates from magnetic field readings.
• Verification of the algorithm using analytical and finite element modeling, and a 3D positioning system.
• Integration of accelerometry for teeth impact detection and testing on a 6-DOF jaw motion simulator.

Main Results:

• The developed algorithm accurately determined coordinates with a root-mean-square error (RMSE) of 0.328±0.005 mm for a 10 mm cubic trajectory.
• The system demonstrated the ability to detect teeth impacts.
• Testing on a hexapod-based jaw motion simulator confirmed simultaneous detection of jaw position and teeth impacts at natural speeds.

Conclusions:

• A miniaturized system using MEMS sensors (magnetometer and accelerometer) can enable continuous, non-restrictive 24-h intra-oral jaw tracking.
• This technology offers potential for detailed visualization of jaw movement in 3D models.
• The system could facilitate new research avenues into parafunctional jaw activities, such as bruxism.