Abstract: This paper presents a novel three-dimensional finite element generation method for assessing the biomechanical behavior of multi-connected complex teeth and mandible structure. Tetrahedron was chosen as the basic element type for its adaptability to structures with different geometrical complexities. The element generation was implemented by combining two tetragons in adjacent image slices. By examining all combinations of tetragons and their degradations, a software system was developed for interactive element generation, which results in a series of tetrahedrons based on the principle that each combination should lead to elements with exact and close connection. Extensive validation was performed to ensure the accuracy of the algorithm. The method was applied to an occlusive functional analysis of dental prosthetics, generating 4762 nodes and 18534 tetrahedral elements with 9 different materials.