This study evaluated stresses generated at maxillary central incisor (21) root restored with lithium disilicate crown (LDC), and glass fiber (GFP) or polyetheretherketone (PEEK) post. 3D models created by computed tomographic image (i-CAT Cone Beam 3D Dental Imaging System) reproduced maxillary central incisor. Each model had prosthetic LDCs (2.0 mm thick) cemented to GFP or PEEK posts with dual resin cement. Different loads were applied to each model (cervical, incisal, axial, middle). At maximum principal stress, PEEK showed higher stress than GFP in all loads, but with qualitative similarity. At minimum principal stress, PEEK and GFP showed qualitative and quantitative similarities, except axial load. Maxillary central incisor restored with GFP or PEEK and LDC presented, in general, similar stress intensity and distribution for main occlusal loads. Only two of sixteen occlusal loads tested (cervical for maximum principal; axial for minimum principal) showed significant quantitative difference.