The Effect of Pore Size in 3D-Printed Porous Titanium Implant on Osseo-Integration: (An in Vivo Study)

Porous titanium structures have recently gained considerable popularity among researchers in studies examining bone ingrowth and osseointegration. Porous implants fabricated using triply periodic minimal surface design (TPMS) and designed through 3D printing techniques exhibited remarkable mechanical strength and cell viability compared to conventional implants. This study aimed to evaluate the effect of pore size of titanium implants with gyroid structure.

This study was conducted on Adult male Wistar rats weighing 350 and 450 g for the animal study by the calvarial defect model to investigate bone regeneration. Three disk-shaped implants were designed using a gyroid structure with pore sizes of 400, 500, and 600 micrometers. All implants were made by additive manufacturing (Selective Laser Melting) using Ti6Al4V medical-grade powder. Animals were sacrificed after 12 weeks, the skin was removed from the calvaria, and the implants were removed for histological examination.

Gyroid structures had a high surface-to-volume ratio and pore connectivity, facilitating cell adhesion and ossification. A significant amount of bone ingrowth was observed in the 400 mm group, so that bone penetrated into pores significantly more than in the other groups. However, the vascularization was more pronounced in the 600 μm group than in the other groups.

According to the results, there was a positive effect of porosity in titanium implants in encouraging bone ingrowth. The porosity size of 400 μm was more suitable for the differentiation and proliferation of bone cells and thus the osseointegration in porous titanium implants with gyroid structure.