Skeletal response to maxillary protraction with and without maxillary expansion: a finite element study

Area of Science:

• Orthodontics and Craniofacial Biology
• Biomechanical Analysis
• Finite Element Modeling

Background:

• Skeletal Class III malocclusion often involves maxillary retrognathia.
• Effective treatment requires understanding craniofacial structure displacement.
• Finite element analysis provides a biomechanical evaluation of treatment modalities.

Purpose of the Study:

• To biomechanically compare maxillary protraction alone versus combined with maxillary expansion.
• To analyze the displacement of craniofacial structures under different treatment simulations.
• To determine the optimal treatment strategy for maxillary retrognathia.

Main Methods:

• Developed two 3D finite element models from CT scans of a young skull.
• Simulated maxillary protraction forces (1 kg anterior, 30° downward).
• Simulated maxillary protraction with 4 mm midpalatal suture expansion.

Main Results:

• Maxillary protraction alone caused forward nasomaxillary displacement with rotation.
• Combined protraction and expansion showed greater displacement and no rotation.
• Combined treatment more closely mimicked natural maxillary growth direction.

Conclusions:

• Maxillary protraction with expansion yields more favorable craniofacial displacements.
• This combined approach is biomechanically superior for treating maxillary retrognathia.
• Maxillary expansion enhances the effectiveness of protraction therapy.