Evaluation of Different Bar Materials in Terms of Stress Transmission in All-on-four and All-on-three Concepts: A Three-dimensional Finite Element Analysis

Abstract

Aim: The aim of this study is to evaluate the effects of materials used in bar construction in all-on-four (AOF) and all-on-three (AOT) concepts on stress transmission by three-dimensional (3D) finite element analysis (FEA) method. Materials and methods: Two models were designed to simulate the AOF and AOT concepts in the mandible. For the AOF concept, the mesial implants were placed at the canine teeth position and the distal implants were inclined 40° distally, with the neck portions protruding from the second premolar region on both sides. For the AOT concept, one of the implants was placed in the middle of the two incisors in the mandible and the other two implants were placed distally in the first premolar region. Bars and prostheses were designed and the model parts were combined. Four different bar materials were defined after creating four different models for both concepts. A force of 100 N was applied perpendicular to the long axis of the left first molar tooth from the central fossa. Elastic strain values of bar structures and bone tissue were obtained. Results: The lowest strain values in both AOF concept and AOT concept were observed in the cobalt-chromium bar structure. In both concepts, the lowest strain values in bone tissue were observed in models produced with type IV gold alloy bars, while the highest strain values were observed in models produced with silver-palladium alloy bars. Conclusion: In AOF and AOT concepts, the type of bar material affects the strains in the bar structure and bone tissue. The material with the lowest strain observed in the bar material and the material causing the lowest tension in the bone tissue are not the same. Clinical significance: In the AOF and AOT concepts, which are fixed prosthetic treatment options with a less number of implants, the type of bar material used is important for the success of the treatment.