Influence of Cusp Inclination on Stress Distribution in Implant-Supported Prostheses. A Three-Dimensional Finite Element Analysis Rosse Mary Falc ´ on-Antenucci, DDS, MSc, 1 Eduardo Piza Pellizzer, DDS, MS, PhD, 1 Paulo Sergio Perri de Carvalho, 2 Marcelo Coelho Goiato, DDS, MS, PhD, 1 & Pedro Yoshito Noritomi, MSc, PhD 3 1 Department of Dental Materials and Prosthodontics, Sao Paulo State University, UNESP, Aracatuba, Brazil 2 Department of Surgery, Sao Paulo State University, UNESP, Aracatuba, Brazil 3 Renato Archer Information Technology Center, Campinas, Brazil Keywords Finite element method; dental implant. Correspondence Rosse Mary Falc ´ on-Antenucci, Department of Dental Materials and Prosthodontics, S ˜ ao Paulo State University, UNESP, Dental Materials and Prosthodontics, Rua Jos ´ e Bonif ´ acio 1193, Vila Mendoc ¸ a, Arac ¸ atuba, S˜ ao Paulo 16015-050, Brazil. E-mail: rosse_falcon@yahoo.com.br, rossefalcon@gmail.com Accepted June 2, 2009 doi: 10.1111/j.1532-849X.2010.00582.x Abstract Purpose: The aim of this study was to assess the influence of cusp inclination on stress distribution in implant-supported prostheses by 3D finite element method. Materials and Methods: Three-dimensional models were created to simulate a mandibular bone section with an implant (3.75 mm diameter × 10 mm length) and crown by means of a 3D scanner and 3D CAD software. A screw-retained single crown was simulated using three cusp inclinations (10 ◦ , 20 ◦ , 30 ◦ ). The 3D models (model 10d, model 20d, and model 30d) were transferred to the finite element program NeiNastran 9.0 to generate a mesh and perform the stress analysis. An oblique load of 200 N was applied on the internal vestibular face of the metal ceramic crown. Results: The results were visualized by means of von Mises stress maps. Maximum stress concentration was located at the point of application. The implant showed higher stress values in model 30d (160.68 MPa). Cortical bone showed higher stress values in model 10d (28.23 MPa). Conclusion: Stresses on the implant and implant/abutment interface increased with increasing cusp inclination, and stresses on the cortical bone decreased with increasing cusp inclination. Dental implants are frequently used in the treatment of eden- tulous patients, increasing the treatment possibilities in oral rehabilitation. The high success rate and the great number of patients treated with osseointegrated dental implants over the past 20 years have attracted the interest of clinicians and re- searchers worldwide. 1 Despite the excellent long-term results afforded by the use of implants in dental treatment, they are not free of mechanical complications. 2-4 The biomechanical aspects of dental implants are quite dif- ferent from those of natural teeth, due to the capacity of the periodontal ligament 5,6 to absorb stress and permit tooth mi- cromovement, compared to the osseointegrated implant, which has none. There is a possibility that overloads transferred to the implant and surrounding bone could exceed physiologic limits and jeopardize the health of the implant as well as the supported prosthesis. 2-4 Therefore, it is necessary to op- timize the distribution of occlusal loads between the prosthesis, the implant, and the surrounding bone. 7,8 Load transfer at the bone/implant interface depends on the type of loading, 9,10 the material properties of the implant and prosthesis, the quality and quantity of the surrounding bone, 10 the implant geome- try (length, diameter, and shape), 11-15 and the implant surface structure. 11 Some analyses have pointed out that the occlusal configura- tion and cusp inclination of implant-supported prostheses play a significant role in force transmission and the stress-strain relationship between the prosthesis and the bone. 8,13,16 Cusp inclination could increase lateral forces when vertical loads are applied on occlusal surfaces. 7,13,17 Therefore, it is important to not only consider both axial (vertical load) and horizontal forces during stress analysis of the dental implants, but also to con- sider the more realistic case of combined loads (oblique load) since for a given force these will cause the highest localized stress in cortical bone. 18,19 The analysis of mechanical behavior in response to stress can be accomplished using techniques such as photoelastic- ity, strain gauge measurements, and finite element analysis (FEA). 12 When the evaluation involves complex geometries, Journal of Prosthodontics 19 (2010) 381–386 c  2010 by The American College of Prosthodontists 381