Segmental defects in the mandibular bone can occur after local trauma, infection, or surgical resection. Several reconstructive possibilities are currently available, and temporary stabilization of bone segments with reconstruction plates is commonly used when immediate bone reconstruction is not possible. However, little attention has been paid to the biomechanical aspects involved in this approach, and studies conducted with biomodels face the difficulty of simulating the muscular forces involved. The use of Finite Element Analysis allows for the mathematical evaluation of structures in a controlled environment, applying forces at any point and/or direction, assessing material deformation, as well as the tension applied to them. Thus, the aim of this study was to evaluate reconstruction plates used on segmental defects through mathematical analysis using finite elements. After simulation, lower stress values were found on thicker plates, suggesting greater resistance to fracture. Conversely, significantly increased stress values on the screws were present in thicker plates.