Mechanical behaviour of dental implants

Dental implants are in general made of titanium, since this material promotes a stable and functional connection between the bone and the surface of the implant. Efforts produced during the chewing cycles may interfere with this union, affecting the process of osseointegration and eventually compromising the stability of the implant. Given the difficulty in working with bone in vivo, in the present study two implant systems were inserted in polymer samples, known as Sawbones, which simulate the structure of trabecular bone. The performance of the implants was evaluated through experimental fatigue tests. The qualitative analysis of the damage in the structure of the samples was performed using scanning electron microscope images. Determination and comparison of stress fields and deformations at the Sawbone-implant interface using an analytical model of indentation and the finite element method (FEM) to model indentation and penetration were undertaken. The experimental results showed that the performance of the Morse taper implant was greater than the external hexagonal implant when both were tested cyclically in samples of different densities. It was shown that the diameter, length, density and type of implant-abutment interface affected the behaviour of the implants. The numerical results of indentation model were very similar to those obtained by the analytical model. The results of the FEM penetration model had the same tendency as the experimental values and the indentation analysis with increasing the density of the polymer foam. It could be concluded that, as in foams, the increase of the bone density will induce an increased stability to the implants.