Abstract: Objective：To compare the difference of implant and cortical bone stress value and the deformation value of titanium frame, in the design of All-on-Four and maxillary sinus floor augmentation with varies bone qualities, using finite element analysis in maxillary edentulous with insufficient bone mass in posterior tooth area. Methods:The CBCT data of a maxillary edentulous was selected to establish the solid models of D2, D3 and D4 bone quality. Two implant schemes were designed under each kind of bone quality, and a total of 12 models were applied 200 N vertical load on both posterior teeth with or without cantilever. Then, the von Mises stress values of implants and cortical bones and the deformation of titanium frame were calculated and statistically analyzed. Results:The von Mises stress of implant and cortical bone and the deformation of titanium frame with cantilever were significantly higher than those without cantilever, and the difference was statistically significant (P＜0.05). The von Mises stress of implant and cortical bone and the deformation of titanium frame in maxillary sinus floor augmentation group were lower than those in All-on-Four group, and the difference was statistically significant (P＜0.05). When the bone type was D4, the von Mises stress value of implant and cortical bone and the deformation of titanium frame were the largest. With the increase of bone quality, the von Mises stress value of implant and cortical bone and the deformation of titanium frame decreased gradually. Conclusions:The maxillary sinus floor augmentation showed more favorable biomechanical behavior than All-on-Four, which was suitable for all kinds of bone qualities. The increase of bone quality was beneficial to the overall stress distribution. When the bone type was D2, we could consider choosing All-on-Four for repair, but the cantilever should be reduced oravoided. When the bone type was D4, the All-on-Four technique should be used cautiously.

Key words: implant restoration, maxillary edentulous jaws, All-on-Four, maxillary sinus floor augmentation, bone quality, finite elements analysis