The biomechanics of dental implants and dentures

Abstract

Osseointegrated implants are actually replacements for natural teeth, and, like natural teeth, they are exposed to various forces. Rejection and bad osseointegration of implants rarely occur today because oral implants are made from biocompatible materials. Most complications are a consequence of badly planned implant loading. The aim of this work was the optimization of the process of planning and inserting oral implants and dentures based on the analysis of the biomechanical problems in implantology. In order to determine the influence of the number of cantilevered superstructures, the number of implants and implant microdesign on tensions within the implant and in the peri-implant tissue, a calculation of tensions and deformations was made in a virtual model (control model) using the finite elements analysis. The obtained values served as reference values in the analysis of the results from three experimental models. In the control model, as well as in the experimental models, the first implant bears the heaviest load with dominant contraction tensions, the second one carries significantly weaker straining tensions, the third one carries weak contraction tensions and the fourth one the weakest straining tensions. The values of tensions and deformations have the same sign (-/+), but the absolute values depend on the number of cantilevered superstructures, implant microdesign and the number of inserted implants. Knowing the biomechanics of oral implants and the dentures on them allows for proper indication, a good choice of implants and good superstructure design. The prevention measures for bone resorption caused by biomechanical factors are: insertion of symmetrical screw implants and root-shaped cylindrical implants as long and as wide as possible, insertion of implants with the total supporting area expanded, choosing materials that are rigid enough, the right direction of implants, narrowing of the denture occlusal surfaces and location of the contact point at the centre.