Abstract: Objective To analyze the influence of platform switching with different implantabutment mismatch sizes on the stress distribution of the implant system and bone tissue. Methods Based on the Ankylos implant system (Ankylos C/X 4.5 mm×11 mm), four 3D finite element models were simulated by using Mimics, Solidworks, and Patran software, with both vertical and oblique load on each model. The implantabutment mismatch sizes of different models were 0.0, 1.0, 1.5, 2.0 mm respectively. The Von Mises stress and the trend of stress distribution were analyzed in each model. Results Compared with the platformmatched implant, the group of platformswitched implant had a lower maximum Von Mises stress in the periimplant bone. With the increase of mismatch size, the stress concentration in the cortical bone was found to decline. However, when the mismatch size was no less than 2 mm, the stress concentration in cortical bone was observed to show an increased tendency. Conclusions The amplitude of horizontal mismatch may have a positive effect on the reduction of the stress concentration on implantbone interface. On the contrary, there is an increasing tendency in the stress concentration with the excessive increase of mismatch size.

Key words: platform switching, implants, horizontal mismatch, threedimensional finite element