Plateau implants- would cancellous bone withstand the functional loading when involved in bone loss?

Abstract

Crestal cortical bone at the implant neck is the key structural element of the jaw, which withstands the functional loading. Bone loss progression results in overloading of "soft" cancellous bone with the risk of implant failure. Comparing to conventional ones, short implants should be more sensitive to this issue. Plateau implants reduce the impact of bone loss, but there is no quantitative confirmation to this.The aim of this study was to assess the load-bearing ability of cancellous bone on several levels of bone loss after it propagates through the crestal cortical bone.Cancellous bone von Mises stresses (MESs) were proposed to evaluate loadbearing ability of fully and partially osseointegrated 4.5 (N), 5.0 (M), 6.0 mm (W) diameter and 5.0 mm length Bicon SHORT® implant on 5 levels of bone loss from 1.2 to 2.0 mm. Implant 3D models were placed crestally and bicortically in posterior maxilla segment models with type III bone and 1.0 mm cortical crestal and sinus bone. Bone models were drawn in Solidworks 2016 software. Materials were assumed to be linearly elastic and isotropic. Elasticity moduli of cortical/cancellous bone were 13.7/1.37 GPa. Bone-implant assemblies were analyzed in finite element (FE) software Solidworks Simulation. 4-node 3D FEs were generated with a total number of up to 2,516,000. 120.92 N oblique load was applied to the center of 7 Series Low 0°a butment. MESs were evaluated in cancellous bone-implant interface for fully and partially osseointegrated implant and were compared.6.0, 5.0, 3.5 MPa maximal MESs for the osseointegrated N, M, W implants were found in cancellous bone at the first fin. For 1.2, 1.4, 1.6, 1.8, 2.0 mm bone loss, maximal MESs were calculated in migrating critical points of cancellous bone-implant interface, which were located on the border of disosseointegrated-osseointegrated cancellous bone