A finite element model of the 3D-printed transparent facemask for applying pressure therapy

Background: Transparent facemask has been widely used for the prevention and treatment of facial hypertrophic scars all over the world. 3D printing has improved the fabrication accuracy of the traditional transparent facemasks. However, the pressure distribution pattern generated by the 3D-printed transparent facemasks has not been thoroughly investigated. The aim of this study is to develop a biomechanical model to simulate the pressure distribution of the 3D-printed transparent facemask, and to form the biomechanical basis to guide facemask design. Methods: A finite element model comprised of the head bones, the soft tissues of the face and the transparent facemask was established in ABAQUS CAE package. The contact pressure between the facemask and the face was simulated under 7 loading conditions. The calculated results from the model were validated through comparing with the experimental pressure measurements. Findings: The calculated results from the model well correlated with the experimental pressure measurements (P < 0.05). The biomechanical model is acceptable for the prediction of interface pressure between the facemask and the face. Interpretation: The pressure distribution pattern showed the facial areas with thin soft tissues and bony prominence experienced concentrated pressure while areas with thick soft tissues received less or no pressure. Suggestions for future facemask design based on the biomechanical model is releasing the areas with concentrated pressure and indenting areas with insufficient pressure.