Optimization of Tilted Implant Geometry for Stress Reduction in All-on-4 Treatment Concept: Finite Element Analysis Study.

PURPOSE: The aim of this work was a finite element analysis of the effect of a sloped platform in tilted implants in the All-on-4 treatment concept on the level of maximum stresses in compact bone. MATERIALS AND METHODS: Finite element modeling of the stresses at tilted microthread implants with standard and sloped abutment platform under four loading conditions and two levels of osseointegration was performed. RESULTS: The sloped abutment platform in tilted implants positioned at rim bone level resulted in a two to four times reduction of the maximum von Mises stresses in the adjacent cortical bone compared with the standard platform. These stresses were well below the yield stress of the cortical bone. The main importance of the proposed sloped platform in tilted implants is substantial stress reduction in the case of immediate loading. The stress reduction also results in the reduction of the deformation of the framework of the All-on-4 concept. CONCLUSION: The suggested modification of the slope of the abutment platform on tilted implants is recommended as a technically simple and highly effective solution for significant reduction of maximum stresses in the cortical bone around the implant.