Structural design of gradient porous dental implant based on orthogonal test.

Objectives: To solve the current problems of loosening and dislodging caused by the high elastic modulus of solid implants, we attempted to study a gradient porous dental implant that can lower the stress concentration and reduce the elastic modulus.

Methods: SolidWorks software was utilized to design the abutment and mechanical structure of the gradient porous implant. The mechanical properties of the gradient porous implant were evaluated by an orthogonal experimental design from four aspects: pore shape, pore diameter, porous layer height, and circumferential distribution. ANSYS software was used to evaluate the distribution of Von-Mises stress in the implant and its surrounding bone tissues under different structural combination parameters to derive the optimal combination of gradient porous implant parameters.

Results: The effects of the four factors, namely, pore shape, pore diameter, porous layer height and pore distribution, on the maximum Von-Mises stress on the implant were as follows. As the pore shape became smaller and the circumferential distribution decreased, the Von-Mises stress decreased significantly. The pore diameter went from 500 μm to 600 μm and then to 700 μm. The Von-Mises stress decreased and then increased. It increased with the increase in the height of the porous layer.

Conclusions: The final optimal combination of parameters for the gradient porous implant was as follows: square pore shape, pore diameter of 600 μm, porous layer height of 3 mm, and quadratic step in pore distribution.