Nonlinear finite element analysis of three implant–abutment interface designs

The objective of this study was to investigate the mechanical characteristics of implant–abutment interface design in a dental implant system, using nonlinear finite element analysis (FEA) method. This finite element simulation study was applied on three commonly used commercial dental implant systems: model I, the reduced-diameter 3i implant system (West Palm Beach, FL, USA) with a hex and a 12-point double internal hexagonal connection; model II, the Semados implant system (Bego, Bremen, Germany) with combination of a conical (45° taper) and internal hexagonal connection; and model III, the Brånemark implant system (Nobel Biocare, Gothenburg, Sweden) with external hexagonal connection. In simulation, a force of 170 N with 45° oblique to the longitudinal axis of the implant was loaded to the top surface of the abutment. It has been found from the strength and stiffness analysis that the 3i implant system has the lowest maximum von Mises stress, principal stress and displacement while the Brånemark implant system has the highest. It was concluded from our preliminary study using nonlinear FEA that the reduced-diameter 3i implant system with a hex and a 12-point double internal hexagonal connection had a better stress distribution, and produced a smaller displacement than the other two implant systems. Modeling of dental implant systems with nonlinear finite element analysis (FEA) can differentiate their resistance to physical stress. Chun-Bo Tang of Nanjing Medical University, China, along with dental and engineering colleagues in Nanjing, tested the FEA method in a study of three commonly used designs of implant from different countries. In three dimensions, they simulated the stresses of a force of 170 newtons exerted at an angle of 45° onto the top of the attachment point or abutment of each system. From their results, Tang and colleagues concluded that none of the implants was likely to fail under such a force. The way the implants distributed stress, however, suggested that the design from the USA was superior to those from Germany and Sweden, and was likely to be displaced a smaller distance when in use.