Micrometer‐Scale Biomechanical Characterization of Oral Mucosa Using Spatial Phase‐Gradient Tracking Optical Coherence Elastography

We present a custom‐built, high‐speed optical coherence elastography (OCE) system for non‐invasive, quantitative assessment of oral tissue biomechanics. The system integrates low‐frequency (10 Hz) air‐driven elastic wave excitation with phase‐resolved optical coherence tomography (OCT) for micrometer‐scale elasticity mapping. A pilot study on human buccal mucosa (four healthy, four cancerous, one leukoplakia) revealed distinct biomechanical contrasts. Healthy tissues exhibited regular elastic wave propagation (≈2.5 μm displacement; 2.72 ± 0.27 Pa modulus), while cancerous samples showed restricted displacement (≈1 μm; 9.51 ± 0.95 Pa), indicating increased stiffness. The elastograms also visualized keratin layer thickening, rete peg elongation, and mild inflammatory infiltration. The leukoplakia specimen demonstrated intermediate stiffness (5.47 ± 0.55 Pa), suggestive of early biomechanical alteration. The integration of air‐pressure excitation with phase‐resolved OCT enables a non‐contact, repeatable, and sensitive elastographic method capable of detecting subtle mechanical changes, highlighting the system's potential for early oral cancer diagnosis and soft tissue biomechanical characterization.