A finite element study of the influence of upper lip pressure on the development of maxilla after cleft lip surgery

PURPOSE To explore the mechanism of upper lip pressure on maxilla after cleft lip surgery. METHODS ANSYS 17.0 software was used to add the upper lip soft tissue to the finite element model of maxilla with cleft palate, and the material properties was assigned to form a three-dimensional finite element model of maxilla with upper lip. The upper lip pressure was applied to the model and force analysis was performed in 2 groups. In the experimental group, upper lip pressure with cleft lip surgery was applied; in the control group, upper lip pressure in normal children of the same age was applied. RESULTS Maxillary deformation in the experimental group was greater than that in the control group. Maxillary deformation occurred in three-dimensional direction, which was mainly in Z axis, followed by X axis and Y axis. The anterior segment of alveolar process was the most obvious，and from the anterior to the posterior, the change trend was gradually decreased. CONCLUSIONS Maxillary growth is inhibited in three-dimensional direction,which is mainly sagittal growth inhibition,followed by transverse and vertical growth. The inhibition gradually decreases from anterior to posterior.