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3D Printing Technologies in Metallic Implants
Table 2. Brief information about the characteristics and outcomes of 3D printed Ti-based porous scaffolds
AM method Characteristics Results References
SLM Dimensional accuracy is dependent on printing [4]
parameters, such as laser power, scanning speed,
and power layer thickness. The 10% porosity
reduction results in a 100-MPa increase in
Diamond lattice pore structure, porosity compression strength. New inward bone tissue
66.1 – 79.5%, pore size 0.65 mm, strut growth was observed in both cancellous and
diameter 0.2 – 0.4 mm compact bone within 0.4 mm strut diameter and
66.1% porosity
SLM Well-defined pore distribution with proper [119]
interconnectivity, the small pores are helpful
for cell adhesion, the large pores improve cell

Interconnecting channels with various proliferation. Pores with about 600-μm size are
diameters (500, 700, and 900 μm) beneficial for bone ingrowth, maturation, and
bone-implant fixation stability
SLM The TPMS method is suitable for obtaining [120]
functional graded structures that mimic natural
bone. Gyroid and diamond unit cells possess a
Three gradient patterns (cell size, density, suitable strength (152.6 MPa and 145.7 MPa)
heterostructure), gyroid and diamond and comparable elastic modulus (3.8 GPa) with
unit cells with triply periodic minimal compact bone. The pore size gradient does not
surfaces (TPMS) lead to considerable density alterations
SLM TMPS structures well resembled the topological [121]
properties of trabecular bone, high fatigue
resistance, and endurance limit as high as 60% of
their yield stress. It has comparable morphology
TPMS porous structures, from left and permeability values with trabecular bone.
to right: primitive, I-WP, gyroid, and Excellent mechanical properties such as low
diamond elastic modulus and high yield strength
SLM Other favorable properties are high compressive [122]
strength, improvement of bone integration,
enhanced cell growth, maximum calcium
deposition in 400 um pore size, and better
Dense center and graded periphery osteointegration. Spider web structures show
structure, porosity in the range of 50 – higher Young’s modulus values. Web structures
80% (70% porosity) and diamond unit structures
(porosity 50%) share almost similar mechanical
properties
EBM Porous structure minimizes the stress- [123]
shielding effect. Other beneficial effects are
increased osteoblasts function, cell adhesion,
proliferation, proteins’ function, and calcium
deposition. Smaller pore sizes have better
biological performance than larger ones

Dodecahedron unit cells with various
pore sizes (600, 400, and 200 μm).
Porosity 65%, with 500 μm strut sizes
(Contd...)

36 International Journal of Bioprinting (2021)–Volume 7, Issue 7