Effect of Occlusal Contact States on Load Distribution for Implants and Natural Teeth：A Simulation Study

Abstract

In case of the coexistence of implants and natural teeth in the oral cavity, we need to consider the strength of occlusal contact, because there is a difference of tissue displacements between implants and natural teeth. However, regarding the optimum occlusal contacts of superstructure of implant prosthesis, there are still many unclear points. Therefore, we simulated the effect of occlusal contact states on load distribution for implants and natural teeth to establish a guideline for the occlusal contact of a superstructure of implant prosthesis.
For natural teeth which have good periodontium (the first premolar) and an osseointegrated implant, we made a graph expressing the relation of the occlusal pressure and the amount of tissue displacement. Based on the graph, we simulated the amount of tissue displacement and the load distribution at the centric occlusal position between natural teeth, between a natural tooth and an implant, and between implants.
The results were as follows: Load distribution on the implant part without a periodontal ligament was large. However, in the early stages of chewing,the load of an implant and a natural tooth became comparable by giving a gap. In addition, during strong biting, the load of an implant and a natural tooth was comparable giving no gap, but if giving a gap larger than 20 μm， there was a case when the load distribution on a natural tooth was larger than that on an implant.
In conclusion, it is suggested that it is not necessary for the superstructure of implant prosthesis to have lighter occlusal contact than natural teeth.