Space maintainers are commonly used appliances in pediatric dentistry to preserve arch length following the premature loss of primary teeth. The long-term success of these appliances depends not only on their clinical stability but also on their biomechanical compatibility. Finite Element Analysis (FEA) is an advanced engineering method that simulates the mechanical behavior of complex structures in a digital environment. In recent years, FEA has been increasingly applied in dentistry. Regarding space maintainers, FEA offers significant advantages in evaluating stress distribution, identifying weak points, and optimizing design and material selection. With the advancements in digital scanners and 3D printing technologies, FEA has become an indispensable part of individualized appliance design and production. This chapter discusses the fundamental concepts, methodological approaches, literature findings, and future perspectives on the use of FEA in the evaluation of space maintainers. Integrating biomechanical analysis with clinical data aims to establish more evidence-based and durable treatment protocols in pediatric patients.