Aim: This study evaluated the influence of different access designs on maxillary two-rooted premolar teeth to assess their biomechanical behavior using finite element analysis. Methodology: Three simulated FEA models were accessed with three main different access cavity designs: the intact tooth (IT) model, the traditional access cavity (TAC), and the conservative access cavity (CAC). Two different radicular preparations were done for each simulated model. The buccal and palatal canals were prepared to the apical sizes #30/.04, and #40/.04. A cyclic load of 50 N was applied on the occlusal surface. The patterns of stress distribution, the maximum von Mises (VM), and maximum principal stresses (MPS) were evaluated and determined mathematically.