Influence of cusp inclination in implant supported dentures

Objectives: The aim of this research was to assess the influence of cusp inclination on stress distribution in implant supported dentures, by the three dimensional finite element method.

Method: Three mandibular models were made with the aid of a 3D MDX-20 Scanner (Roland DG, São Paulo, Brazil) and the assisted drawing programs: Rhinoceros® 3D 3.0 (NURBS Modeling for Windows, EUA) and SolidWorks® 2006 (SolidWorks Corp, Massachusetts, USA). By means of these, a block of mandibular bone was simulated, with the presence of a single implant (Conexão Master Screw, São Paulo, Brazil) with a metal-ceramic crown with 3 different cusp inclinations (10°, 20° and 30°). The three dimensional drawings were exported to the finite element program NEiNastran® 9.0 (Noran Engineering, Inc., USA), to determine the regions, generate the finite element meshes and analysis. An oblique 200N load was applied, fractionated into 100N per point (2 points), on the grinding slopes of the vestibular cusps of the metal-ceramic crown of the second molar. The results were obtained by means of von Mises stress maps.

Results: The implant showed the highest stress value in Model C (cusp of 30°) (160.6836 MPa); on the cortical bone the highest stress value was shown in model A (cusp of 10°) (28.23944 MPa).

Conclusion: With increase in cusp inclination, there was an increase in stress on the implant and diminished stress on the cortical bone.