The periodontal ligament as a mechanical connection between the tooth and the bone, plays a fundamental role in transmitting and absorbing chewing loads, distributing stress in the alveolar bone, and facilitating tooth movement during orthodontic treatments. This tissue exhibits time-dependent mechanical behavior due to its complex structure, which includes a network of oriented collagen fibers and a porous, fluid-saturated environment. Therefore, a detailed understanding of the mechanical behavior of the periodontal ligament, especially considering its two-phase performance, is one of the most challenging topics in the field of dental biomechanics. In the present study, the analysis of the biphasic mechanical behavior of the periodontal ligament under orthodontic loading conditions was investigated using the finite element method. In this analysis, the hydromechanical coupling theory has been used to simulate the interaction of the solid phase and the fluid within the ligament. Also, the theory of transverse isotropic hyper elasticity has been used as an innovation of this research in modeling the solid phase behavior of collagen fibers, which has led to the implementation of the UMAT subroutine in the Abaqus software. The results of this simulation show that simultaneously considering hydro mechanical effects and spatial orientation of fibers within a comprehensive and flexible framework as an efficient analytical tool in dental biomechanics, allows for more accurate prediction of mechanical responses of teeth to orthodontic forces