Finite Element Analysis of Two Different Implant Applicable for Vertical Bone Deficiency at Maxillary Sinus

Objective: The critical point of the sinus floor elevation procedure is retaining the membrane intact. The BoneTrust Sinus (c) (BTS) implant system is recommended by the manufacturer as it could protect the membrane from perforation and provide greater primary stability. The aim of this study was to evaluate the stress distribution on the surrounding bone and implant body of this implant design compared with the conventional BoneTrust Plus (c) (BTP) design using three-dimensional (3D) finite element analyses (FEAs). Study Design: Six different finite element models, including two implant designs of three different graft qualities (high-stiff, medium-stiff and low-stiff), were prepared for the implant surgery on an atrophic edentulous maxilla with sinus pneumatization of a healthy individual. Then, these models were loaded with vertical and 30 degrees oblique forces. With 3D FEAs, stress distributions of these models were obtained, color-coded, and shown numerically. Results: According to the results of the study, oblique loading caused higher stress than vertical loading. The stresses were highest in the crestal cortical bone, lower in the graft, and lowest in the trabecular bone. In addition, BTS implant design had similar stress distribution values on the implant body, the surrounding bone, and the graft as did the conventional BTP design. Conclusions: The BTS implant design could be effective in stress distribution similarly to the conventional design and could even be preferable because of its clinical advantages. Additionally, these are obtained that supported cortical bone thickness, graft quality and angular parallelism between implants and occlusal forces are important factors in terms of load-bearing capacity.