Ricardo Augusto Conci1, Flavio Henrique Silveira Tomazi2, Pedro Yoshito Noritomi3, Jorge Vicente Lopes da Silva4, Guilherme Genehr Fritscher5, Claiton Heitz5. 1. Specialist and Master of Oral and Maxillofacial Surgery, PhD Candidate in Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil. Electronic address: ricardo_conci@hotmail.com. 2. Specialist and Master Candidate in Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil. 3. Mechanical Engineer, Three-Dimensional Technologies Division, Renato Archer Center for Information Technology, Brazilian Ministry of Science and Technology, Campinas, Brazil. 4. Chemical Engineer, Three-Dimensional Technologies Division, Renato Archer Center for Information Technology, Brazilian Ministry of Science and Technology, Campinas, Brazil. 5. Professor, Department of Oral and Maxillofacial Surgery, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
Abstract
PURPOSE: To compare the mechanical stress on the mandibular condyle after the reduction and fixation of mandibular condylar fractures using the neck screw and 2 other conventional techniques according to 3-dimensional finite element analysis. MATERIALS AND METHODS: A 3-dimensional finite element model of a mandible was created and graphically simulated on a computer screen. The model was fixed with 3 different techniques: a 2.0-mm plate with 4 screws, 2 plates (1 1.5-mm plate and 1 2.0-mm plate) with 4 screws, and a neck screw. Loads were applied that simulated muscular action, with restrictions of the upper movements of the mandible, differentiation of the cortical and medullary bone, and the virtual "folds" of the plates and screws so that they could adjust to the condylar surface. Afterward, the data were exported for graphic visualization of the results and quantitative analysis was performed. RESULTS: The 2-plate technique exhibited better stability in regard to displacement of fractures, deformity of the synthesis materials, and minimum and maximum tension values. The results with the neck screw were satisfactory and were similar to those found when a miniplate was used. CONCLUSION: Although the study shows that 2 isolated plates yielded better results compared with the other groups using other fixation systems and methods, the neck screw could be an option for condylar fracture reduction.
PURPOSE: To compare the mechanical stress on the mandibular condyle after the reduction and fixation of mandibular condylar fractures using the neck screw and 2 other conventional techniques according to 3-dimensional finite element analysis. MATERIALS AND METHODS: A 3-dimensional finite element model of a mandible was created and graphically simulated on a computer screen. The model was fixed with 3 different techniques: a 2.0-mm plate with 4 screws, 2 plates (1 1.5-mm plate and 1 2.0-mm plate) with 4 screws, and a neck screw. Loads were applied that simulated muscular action, with restrictions of the upper movements of the mandible, differentiation of the cortical and medullary bone, and the virtual "folds" of the plates and screws so that they could adjust to the condylar surface. Afterward, the data were exported for graphic visualization of the results and quantitative analysis was performed. RESULTS: The 2-plate technique exhibited better stability in regard to displacement of fractures, deformity of the synthesis materials, and minimum and maximum tension values. The results with the neck screw were satisfactory and were similar to those found when a miniplate was used. CONCLUSION: Although the study shows that 2 isolated plates yielded better results compared with the other groups using other fixation systems and methods, the neck screw could be an option for condylar fracture reduction.