Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

A 3D finite element analysis study was carried out to evaluate the effect of implant tilt on peri-implant bone stress distribution in mandibular cantilevered screw-retained restorations supported by 4 inter-foraminal implants. A three-dimensional models of compact and cancellous bone were constructed in MIMICs medical segmentation software using data from computed tomographic image obtained from an edentulous patient. Planning was made on Blueskyplan software, Implants with some modifications and scan bodies with edentulous cast were exported, then a cantilevered screw retained hybrid prosthesis was designed with a CAD-CAM dental software. All parts were obtained as STL files and converted to solid parts by reverse engineering bio-cad modeling approach in SIEMENS NX software, then assembled in Ansys FEA software, implants were placed on the bone models using a computer guided stent. There were 3 models with distal implants distally tilted (20, 30, 40) degree respectively, the model with angle 30 was the comparator model. All variables rather than implant tilt were standardized for all the 3 models. The material properties for compact bone, cancellous bone, titanium alloy, cobalt-chromium and acrylic resin were identified. Two loading conditions were applied vertical loads and oblique load. The mandible was restrained at the inferior border to avoid total body displacement. The model was meshed and analyzed using finite element analysis iterative solving method in Ansys FEA software and the results were collected

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