Influence of Occlusal Stress on Implant Abutment Junction and Implant Bone Interface: A Finite Element Analysis Study

The aim of the present study was to assess the occlusal stress on the implant-abutment junction and implant-bone interface of a long-span implant-supported prosthesis made of two different prosthetic materials.

A computerized tomography of the mandible was used to get the finite element model of the bone. The comparative groups were made as follows: S1 and S2 - 3.7 × 11 mm (44 region) and 4.5 × 11 mm (47 region), S1A and S2A - screw-retained porcelain-fused-to-metal prosthesis, S1B and S2B - cement-retained porcelain-fused-to-metal prosthesis, S1C and S2C - screw-retained zirconia prosthesis, and S1D - cement-retained zirconia prosthesis. Maximum stress generated on the implant-abutment interface of all the prostheses under vertical and oblique load was assessed.

For all the comparative groups, maximum level of stress was generated at the cervical level of the implant-bone interface in comparison to the apical and middle-third level under both vertical and oblique load. No statistically significant difference between zirconia and porcelain-fused-to-metal prosthesis was seen at the implant-abutment interface and the cervical third of the implant-bone interface. A significant difference was found between all screw-retained and cement-retained groups.

The present study concluded that the short implants in combination with standard-length implants using either porcelain-fused-to-metal or zirconia as prosthetic material in the form of long-span implant-supported prosthesis can be a viable treatment option in the posterior mandible.

The accuracy of the diagnosis, examination, and knowledge of the site where the implant must be inserted, and the choice of superstructure is important for the stability and lifespan of the implant prosthesis.