Aim: To biomechanically analyze two fixation techniques in polyurethane hemi-mandibular body fractures, using a universal testing machine. Methods: The study employed 10 polyurethane hemi-mandible replicas, which simulated simple fractures of the mandibular body, divided into two groups: one group comprised 5 hemi-mandibles with two 2.0 mm system plates in the tension and compression zones, while the other group contained 5 hemi-mandibles with an Erich bar and a 2.0 mm system plate in the tension and neutral zones, respectively. Data were analyzed statistically by the Student’s t-test (?=0.05) Results: The test results indicated that the fixation using 2.0 mm system plates offered significantly more resistance to the loads and presented significantly larger displacement compared to the fixation using just one 2.0 mm system plate and the Erich bar. Conclusions: It may be concluded that the use of two plates in the 2.0 mm system had greater mechanical strength than a single 2.0 mm plate combined with an Erich bar. Clinically, it is known that both techniques can provide good results, but patients receiving the combination of Erich bar and one plate are required to be more cooperative during the postoperative period, especially with respect to the prescribed diet in order to avoid failures in this system.12280-83