[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.