Integration of EMG Electrodes by Disruptive 3D Printing Into a Mandibular Brace

Electromyography (EMG) is a crucial technique for measuring muscle activity and is regularly used in motion detection and diagnostics. When applied to small muscles and integrated into devices such as prostheses or force measurement systems, conventional electrodes often fail to meet space and usability requirements. While conductive filaments have been successfully used to additively manufacture electrodes in previous work, these are typically large and not integrated into complex geometries. This work introduces a process employing additive manufacturing with both conductive and non-conductive materials to create integrated, customizable medical sensors with embedded EMG electrodes placed on flexible beams to assess otherwise inaccessible muscles. The process involves a disruption during 3D printing to insert a PCB with a preamplifier, which is then connected by the conductive filament, forming a functional EMG electrode. These EMG electrodes are exemplarily integrated into a mandibular brace for simultaneous measurement of human jaw opening forces and the respective suprahyoid muscle activity. After filtering, an EMG activity with an SNR of 11.6 dB and a correlation coefficient with the jaw opening force of 0.93 was found, validating the working principle of the sensors. This technology holds the potential for application in more complex devices, streamlining their production and eliminating the requirement for manual electrode placement on the patient for each use.