# Assessment of Stress Distribution and Displacement in the Craniofacial Complex between Facemask Therapy and Bone Anchored Maxillary Protraction (BAMP): A 3D Finite Element Study

## TL;DR

This study compares two treatments for Class III malocclusion using 3D modeling to show how each affects skull and facial movement and stress.

## Contribution

A novel 3D finite element analysis comparing stress and displacement patterns of BAMP and facemask therapy in craniofacial structures.

## Key findings

- BAMP caused more anterior displacement of the maxilla compared to facemask therapy.
- Facemask therapy resulted in greater downward and backward mandibular displacement.
- BAMP generated higher stress at miniplate sites, while facemask therapy showed more even stress distribution.

## Abstract

Class III malocclusion presents unique challenges in both diagnosis and treatment. Bone-anchored maxillary protraction (BAMP) and facemask (FM) therapy are common approaches. Finite element analysis (FEA) helps evaluate their biomechanical effects. The study aims to evaluate and compare the stress distribution and displacement during maxillary protraction on the craniofacial complex using bone-anchored maxillary protraction and a facemask using finite element analysis.

A finite element model of the maxillofacial complex was developed using CT scans of a young human skull and analyzed using ANSYS (v18.1). The material properties for facemask therapy and miniplates used in bone-anchored maxillary protraction (BAMP), were gathered to create a 3D finite element analysis (FEA) model. Displacement and stress patterns were assessed in the maxilla, maxillary teeth, mandible, and surrounding structures for both BAMP and facemask therapy, applying a bilateral force of 300 grams.

Displacement was mainly observed in the maxillary complex for both protocols, with BAMP showing more anterior displacement than the facemask. In contrast, the mandible experienced greater downward and backward displacement with the facemask protocol. Both methods revealed distinct displacement patterns in the dentoalveolar area. The facemask treatment resulted in more forward displacement of the maxillary anterior teeth, while BAMP primarily caused forward displacement in the first and second molar regions. Additionally, BAMP showed higher stress levels in the craniofacial area, particularly at the miniplate attachment site, whereas the Facemask approach had a more even distribution of stress across the craniofacial region.

This finite element analysis indicates that maxillary protraction can be achieved through both FM and BAMP methods. However, BAMP method showed greater skeletal displacement with fewer dental effects. This implies that skeletal anchorage might provide a better result for treating class III malocclusion.