Methods: 3D-FEM models were fabricated from DICOM data of 3 edentulous maxillae before implant placement. Four implants were placed in bilateral anterior and premolar regions (φ4.0mm x 11.5mm and φ4.0mm x 13mm). An acrylic resin prosthesis was fabricated between the bilateral second premolars as a control. A reinforced model was then fabricated by attaching a Co-Cr alloy plate with 0.5mm thickness on the lingual surface of the control model. From the CT value of the DICOM data, the Young’s modulus was calculated and configured for each elements of the maxillary bone, while known values of the other materials were used for the other elements. The implant-bone interface was set as the contact condition. The loading condition was set based on the bruxism patient’s data.
Results: The stress concentration as measured by implant displacements and von Mises stress distribution was observed at the surrounding bone in the premolar region on the loaded side. Both averaged maximum implant displacements and von Mises stress were reduced from 147 to 107 µm and from 2.88x102 to 1.58x102 MPa by the reinforcement.
Conclusions: This 3D-FEM study showed that both magnitudes of micro-movement of the implant and associated bone stress were reduced by the reinforcement of provisional prostheses under simulated immediately loaded condition, which suggests that provisional prostheses should be rigid in order to successfully obtain osseointegration of immediately loaded implants.