Fig. 1. Illustration of preparation process of the channel-like porous-structured titanium.

Fig. 2. Morphologies of the as-prepared porous titanium (a-c): pore size = 0.4 mm, porosity = 30%, 40%, and 50%, respectively, Insert: a local magnified image showing the inner surface of the pore. (d) Compressive stress-strain curves of the as-prepared porous titanium with different porosities. (e) Comparison of the compressive strength and modulus of the porous titanium with about 40% porosity fabricated by various methods. (f) Tensile stress-strain curves of the as-prepared porous titanium with different porosities. (g) Comparison of the tension strength and modulus of the porous titanium with about 40% porosity fabricated by various methods. P: porosity.

Fig. 3. Tomography images of porous titanium: (a) Matrix merged with pores, (b) Pores in titanium. The distribution of the wall thickness of porous titanium under different porosities: (c) Region in inner ring (Zone A); (d) Region in outer ring (Zone B).

Fig. 4. In vitro experiments. (a) Viability of MG63 osteoblasts in dense titanium and porous implant scaffolds with different pore size (i.e., 0.3 mm, 0.4 mm and 0.5 mm) using CCK-8 assay. (b) DNA production of MG63 osteoblast cells cultured on dense titanium and porous titanium with different pore size (i.e., 0.3 mm, 0.4 mm and 0.5 mm). (c) Viability of MG63 osteoblasts in porous titanium scaffolds with 0.4 mm pore size and dense titanium scaffolds using live/dead assay. (d) SEM images of primary osteoblast cells adhered to the porous titanium after 1 and 3 days, Insert: a local magnified image showing cells adhered on inside surface. ★p < 0.05, ★★p < 0.01 compared with control group, #p < 0.05, ##p < 0.01 compared with 0.4 mm group.

Fig. 5. Micro-CT 2D images of the implants and surrounding bones (red triangles refer to the newly formed bone).

Fig. 6. (a-d) 3D reconstruction models showing the status of the implants (white in color) and new bone (yellow in color) response. (e-h) Optical micrographs (transverse section) of the porous titanium and dense titanium implanted in rabbit model after 16 weeks postoperation (black: titanium, red: bone, white: pores). d: pore diameter.

Fig. 7. Osseointegration of the porous titanium. (a) Trabecular bone volume fraction, BV/TV, and trabecular number of the new bone ingrew into the implants with different pore size. (b) New bone penetration length in the implants.

Fig. 8. Effect of density (porosity) on tensile strength of the porous titanium. The exponentials of the Gibson-Ashby equations can be determined by the best fitted lines for the data points.