Abstract: BACKGROUND: Studies have shown that the elastic modulus can be changed by changing the pore internal unit structure when designing porous implants, providing a new way to better balance implant strength and elastic modulus.
OBJECTIVE: To analyze dental implant biomechanical properties with different micro pore structures by finite element analysis so as to elucidate the effects of different micro pore structures on the surrounding bone stress and implant physical properties.
METHODS: A mandibular model and three finite element models of dental implants with different pore structures (conventional structural pores, composite structural pores, and G7 structural pores) were built by CT scanning with porosity of 40%, the thickness of the porous layer of 1.2 mm, and the pore size of 0.45 mm. The ultimate force state was simulated to apply load to each model, which was operated by ANSYS finite element software and analyzed by surrounding bone stress and strain of the implants.
RESULTS AND CONCLUSION: (1) When implants were subjected to the ultimate force, the maximum values of effector forces such as 38.324, 56.574, 64.694 MPa for conventional structure, composite structure and G7 structure dental implants on the surrounding cortical bone were respectively 1.836, 10.221, 9.439 MPa, and the maximum values of effector forces such as implants were 156.38, 476.23, 457.76 MPa. The maximum surrounding bone stress of the composite structure implant was within the range of promoting osseointegration. (2) When only lateral forces were applied to the implants, the maximum strain values of dental implants placed in the conventional structure, composite structure and G7 structure were 2.222 9×10-2, 1.661 9×10-2, 3.210 9×10-2 mm/mm. When only axial forces were applied to the implants, the maximum strain values of dental implants placed in the conventional structure, composite structure and G7 structure were 2.266 2×10-3, 1.844 6×10-3, 2.971 5×10-3 mm/mm, indicating that when subjected to lateral static load and axial load, the strain of the composite structure implant was smallest and the micro-movement was small, which helped to improve the osseointegration effect. (3) The results showed that the surrounding bone stress changed significantly with the change of pore unit cell structure inside the porous implant, and the mechanical properties of the implant also changed, and the change of unit cell structure shape of the porous structure on the implant surface significantly affected the elastic modulus and the mechanical properties of the implant. Dental implants with a composite pore structure had better biomechanical properties compared with conventional constructs and G7 constructs.

Key words: dental implants, finite element analysis, biomechanical analysis, micro pore structure, biomechanical properties, bone stress