Finite model analysis of different anchorage sites for bone-supported facemask application in unilateral cleft lip and palate.

Abstract

Introduction: The objective of this study was to evaluate the effects of the miniplate application sites in the maxilla and the applied force vector changes during skeletally supported facemask application in adolescent patients with unilateral cleft lip and palate (UCLP) using finite element model (FEM) analysis.

Methods: A FEM was obtained from a cone-beam computed tomography image of a 12-year-old female patient with UCLP. Miniplates were placed on 3 different sites of the maxilla; 500 g of advancement force was applied bilaterally, parallel (0°), and downward (-30°) to the occlusal plane. Von Mises stress and displacement in the nasomaxillary complex were analyzed.

Results: Von Mises stress values were higher at 0° force mechanics in the nasomaxillary complex in 3 different miniplate sites. In all scenarios, stresses were higher in zygomaticotemporal, zygomaticofrontal, and pterygopalatine sutures. In the y-axis, the amount of displacement was higher in the 0° force mechanics in all models. Midface advancement and clockwise rotation of the nasomaxillary complex were observed in the -30° force mechanics over mini plates placed on the lateral nasal wall and among the premolars, whereas counterclockwise rotation occurred in all miniplate placement sites with 0° force vector.

Conclusions: In patients with skeletal Class III maloclussion with UCLP, anterior placement of miniplates in the maxilla may be a more precise alternative when midface advancement and clockwise rotation of the nasomaxillary complex are desired. This FEM study demonstrated that more anterior placement sites and a 30° force vector is efficacious for maxillary clockwise advancement in UCLP.