Finite element analysis of the dental implant using a topology optimization method.

In recent years, many attempts have been made to optimize the shape of dental implants. The purpose of this study took advantage of the topology optimization in the finite element (FE) method to look for redundant material distribution on a dental threaded implant and redesigned a new implant macrogeometry with the evaluation of its biomechanical functions. Three-dimensional FE models were created of a first molar section of the maxilla and embedded with an implant, abutment and a superstructure by using the commercial software ANSYS 11.0. The final design of a new implant was shaped by topology optimization, and four FE models namely traditional implants with bonded (TB) and contact (TC) interfaces, and new implants with bonded (NB) and contact (NC) interfaces, were established. Material properties of compact and cancellous bone were modeled as fully orthotropy and transversely isotropy respectively. Oblique (200-N vertical and 40-N horizontal) occlusal loading was applied on the central and distal fossa of the crown. The FE model estimated that the volume of the new implant could be reduced by 17.9% of the traditional one and the biomechanical performances were similar, such as the stress of the implant, stress of the implant-bone complex, lower displacement, and greater stiffness than the traditional implant. The advantages of the new implant increased the space to allow more new bone ingrowth or assist in fusing more bone graft into the bone sustaining the implant stability and saved material. Its disadvantage was higher stress level compared with that of the traditional implant.