Stability and Dynamics of Zygomaticomaxillary Complex Fracture Treated Using Non-resorbable and Resorbable 2- and 3-Point Miniplates, Under Physiological and Maximal Occlusal Loads: A Finite Element Analysis

Document Type: Original Article

Authors

1 Associate Professor, Department of Oral and Maxillofacial Surgery and Craniomaxillofacial Research Center, Dentistry Branch of Islamic Azad University of Medical Sciences, Tehran, Iran

2 Private Practice in Dentistry, Tehran, Iran

3 Assistant Professor, Department of Oral and Maxillofacial Surgery and Craniomaxillofacial Research Center, Dentistry Branch of Islamic Azad University of Medical Sciences, Tehran, Iran

4 Assistant Professor, Department of Bio Medical Engineering, Faculty of Bio Medical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

10.30491/tm.2020.214430.1046

Abstract

Background: Zygomatic fractures are the second most common facial injury, knowledge of their management is important. However, fixations methods, which are of importance are variable.
Objectives: Therefore, for the first time ZMC fx, were  evaluated via (FEA)  and dynamics of the zygoma fixed using four 2- and 3-point resorbable plates and  our non-resorbable plates under normal and maximal masticatory loads.
Methods: A maxillofacial CT scan of a man with linear fractures without severe displacements was used to model the zygoma and its adjacent bones. Seven combinations of resorbable and seven combinations of non-resorbable mini-plates 2mm thick were fixed on the zygoma (orbital rim, zygomaticomaxillary buttress [ZMB], and frontozygomatic [FZ]) suture using 6mm miniscrews. ZMB was fixed using an L-shaped 4-hole plate. The infraorbital rim was fixed with a curved 5-hole miniplate. The FZ suture area was fixed with a 4-hole miniplate. The model underwent 150N and 750N loads. Minimum and maximum and rotational displacements, stresses, and strains of the zygoma models were calculated.
Results: Non-resorbable fixation methods can yield much smaller stresses, strains, and displacements compared to resorbable fixations. Adittionally, the parameters were much smaller under the 150N load compared to the 750N load. The worst results belonged to the fixation of the rim and ZMB and the best results belonged to the fixation of ZMB-Rim, FZ-ZMB, Rim-FZ, and FZ-ZMB-Rim.
Conclusion: In patients with heavy masticatory forces, use of resorbable plates are not recommended.

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