Loading influence with heterogeneous periodontal ligament representation in upper incisor

The data about the loading influence on the periodontal ligament (PDL) behavior modeled with beam elements are unclear. Objective: This study evaluated the loading influence on a maxillary central incisor with the PDL modeled with beam3 elements by 2-dimensional finite element analysis. Methods: Two models (MA and MB) of a maxillary central incisor were built varying the PDL fibers representation: MA (homogeneous PDL) and MB (heterogeneous PDL – beam3). The von Mises stress (s_vM), the principal stress in tension (s_max.t) and compression (s_max.c) and displacements were determined for 3 distributed loadings (L) after the numerical analysis (ANSYS 10.0): L1 – 50N in the lingual face, in 45º with the tooth long axis; L2 – 50N perpendicular to the incisal edge; and L3 – 50N parallel to the tooth long axis. Results: L3 provided the smaller s_vM in the tooth and support structures when compared to L1 and L2. For L1, the s_vM (MPa) in the MA was 93.1% lower than that for the MB, and 280% lower for the L2. The PDL representation influence on the s_vM was small in L3. Conclusions: The oblique loadings provided different stress and displacement patterns in the heterogeneous PDL and probably incompatible with the “in vivo” condition. (FAPESP 2006/02336-2)