A skin-adhesive bimodal sensing patch for occlusal function assessment

Occlusal dysfunction is a prevalent orofacial disorder characterized by aberrant occlusal force transmission and dysregulated masticatory muscle activity. Currently, quantitative characterization of occlusion-related neuromechanical activity remains challenging in clinical practice. In this study, we propose a skin-interfaced bimodal sensing patch that integrates serpentine-structured piezoelectric poly(vinylidene fluoride) (PVDF) films with conductive hydrogel electrodes for simultaneous monitoring of facial skin deformation and muscle electrophysiology during occlusal activities. The island-serpentine design ensures high mechanical compliance while preserving stable electromechanical performance over more than 14,000 loading cycles. The hydrogel interface serves not only as an adhesive layer ensuring conformal adhesion of the PVDF film to the skin but also functions as a low-impedance electrode, enabling high-fidelity surface electromyography (sEMG) acquisition with a signal-to-noise ratio of ~30 dB. Through combined analysis of piezoelectric and sEMG signals, the system distinguishes functional occlusal actions, including normal occlusion, deep overbite, crossbite, and mandibular deviation. This bimodal framework provides a preliminary proof-of-concept for multimodal functional characterization of occlusal biomechanics and suggests potential applicability in noninvasive occlusal function assessment.