Effect of Platform Switching on Crestal Bone Stress Distribution around 3i Implants: a Finite Element Analysis

Over the last few years, concept of platform switching has gained popularity for reducing degree of crestal bone resorption. Many researchers believe that, this theory can be used for improving stress distribution in implant-bone interface. The purpose of this three dimensional Finite Element Analysis (FEA) was to study and compare stress distribution in implant-bone interface and implant-abutment interface of 3i implants (Biomet 3i, USA) in mandibular molar area.

For this FEA, computed tomography (CT) images of an adult human mandible was used to make the three-dimensional model of posterior edentulous mandible. The implant systems which used was the 3i system consisted of 3i fixtures: 4 and 5 mm in diameter and 11.5 mm in length, and 3i Certain abutment 4.1 and 5mm (Biomet 3i, USA). This implant systems were assembled on the mandible model in 3 different designs: a platform-switched configuration; MODEL 4: 4-mm 3i fixture, 4.1-mm abutment; MODEL 5: 5-mm 3i fixture, 5-mm abutment; MODEL 6: 5-mm 3i fixture, 4.1-mm abutment, a platform-switched configuration. A linear static analysis was performed on the prepared 3D solid models with two different oblique load of 100 and 250 N in the lingobuccal direction with 15 degrees of inclination on the center of the abutment.

Regardless of the implant system used, maximum Von Mises stresses in cortical bone around implants were lower in platform switched models compared to matching diameter implant-abutment. This effect was not related to the usage of larger implant diameters in these models. However, Von Mises stresses in implant-abutment interface were the lowest in models with larger implant diameter.

The platform switching technique reduces the stress concentration in the area of crestal bone-implant interface and shifted it to the area of implant-abutment interface. In the present study, this stress reduction was not related to increasing Implant diameter.