Role of Pterygomaxillary Junction Morphology in Surgically Assisted Rapid Palatal Expansion: A Finite Element Analysis Study.

Objective: In the present study, the morphological characteristic of the pterygomaxillary junction (PMJ) was determined radiologically and its effects on the maxillary expansion pattern were investigated by finite element analysis.

Methods: The 3-dimensional morphology of the PMJ was measured separately for each dimension by examining 240 cone beam computed tomography of maxilla. Seven maxilla models with different three-dimensional pterygomaxillary characteristics were modeled, and the effect of the structural characteristic of the PMJ on the maxillary expansion pattern, and the stresses in the resistance regions were evaluated by simulating the surgically assisted maxillary expansion.

Results: It has been observed that the factor that increases the stress in the pterygomaxillary region the most with the enlargement of the maxilla is the width, followed by thickness and height. The increase in pterygomaxillary region height led to a decrease in stress. In addition, in models with larger PMJ, stresses in areas such as the zygomatic arch, frontozygomatic suture, and medial pterygoid plate increased. The dimensional increase of the PMJ ended with a gradual decrease in the posterior region in transversal expansion.

Conclusion: According to the results of this study, it can be concluded that the increase in the width and thickness of the PMJ are critical factors in determining the need for osteotomy in this region, especially in cases where the transverse deficiency also includes the posterior maxilla.