Stress Analysis In The Crown/Implant Ratio With Different Connections

Objectives: The aim of this study was to evaluate the influence of crown height of implants with different prosthetic connections, as external hexagon and morse-taper on stress distribution in bone tissue, by the tridimensional finite element method.

Methods: Six three-dimensional models were fabricated using the graphical modeling softwares SolidWorks 2010, Rhinoceros 4.0 and InVesalius. Each model was composed by a bone block, a dental implant (3.75X10mm) by varying the type of prosthetic connection (external hex and morse-taper) and implant-supported single crown with different heights (10,12.5 and 15mm). In the FEMAP 10.2 software, it were generated the finite element meshes and the boundary and loading conditions were established. It were applied an axial (200N) and oblique load (100N) on the occlusal surface of the crowns, then, the analysis was performed in the finite element software, NeiNastran 9.2. The results were visualized by displacement, von Mises stress and Maximum Principal Stress maps.

Results: The displacement was, approximately, three times greater for the larger crown model with external hexagon implant, compared to the morse-taper implant model (15mm); when the crown height increased, under oblique loading, the morse-taper implant model showed the best stress distribution in cortical bone.

Conclusions: The increasing of crown height negatively affected the tendency to displacement in the bone tissue; the increasing of crown height negatively affected the stress concentration in the bone tissue; the morse-taper implant showed a slightly more favorable situation regarding to the tendency to displacement and stress concentration in bone tissue.