Table 3.
Studies that fulfilled the selection criteria and were included for the review in the “Results” section—characterization of the studied materials, methodology, and results
| References | Example application of the material | Type/additional material processing | Determination of physical and chemical properties of the materials | Results |
|---|---|---|---|---|
| Human osteoblasts (OB) | ||||
| Bordji et al. [33] | Orthopedic implants | Stst AISI 316 L implanted with (1) N-implanted, (2) C-doped, (3) nitrided, (4) untreated | Chemical composition (surface layer) EPMA, microhardness (Vickers), wear, and corrosion resistance | Surface treatment improved the mechanical properties; surface characterization—corrosion, wear resistance, and microhardness improved (by ion implantation or carbon coating) |
| Ryhänen et al. [34] | Orthopedic implants | Nitinol (Unitec), Stst AISI 316 LVM, ASTM Grade 2 commercially pure Ti, composite material Silux Plus®, white soft paraffin | Determination of corrosion rate by GFAAS | Corrosion rate: Ni initial release order: Nitinol > Stst; after 2 days: Nitinol = Stst |
| Schmidt et al. [35] | Dental, orthopedic implants | Pure Ti (cpTi), Ti–6Al–7Nb, Stst, Thermanox (control) | Material surface characterization—roughness (profilometer AFM) and SEM | SEM: Thermanox—very smooth surface with almost no elevations and depressions; stainless steel—smooth surface with some humps uniformly distributed; traces from surface polishing; pure titanium—depressions of different depths resulting from the manufacturing process; edges of the holes smooth; scratches on the material surface; titanium alloy—prominent ridges of about 5–10 mm |
| Bogdanski et al. [36] | Orthodontic wires, implants, bone substitute materials | Pure Ni, NiTi alloy (with variable Ni and Ti content, 10 samples), pure Ti | Microscope characterization of biomaterials; XRD | The composition of ten different sections was consistent with the phase diagrams—different intermetallic phases |
| Hao et al. [37] | Internal fixation devices | Stst 316 LS modified by CO2 laser treatment | Surface analysis (SEM), XPS, surface profiling/surface roughness | Wettability positively correlated with proliferation of cells; roughness depended on electric field intensity of laser CO2 treatment, at 1,500 W, which was higher than when treated with 2,400 W |
| Human osteoblast-like cells | ||||
| Riccio et al. [38] | Biomaterials | Stst, Ti alloy, Co–Cr–Mo alloy, carbon fiber-reinforced polybutylene terephthalate, hydroxyapatite | –b | –b |
| Bogdanski et al. [36] | –a | –a | –a | –a |
| Torricelli et al. [39] | Orthopedic implants | Stst P558, Ti6Al4V (Ti alloy), polystyrene wells (control) | Surface roughness, chemical composition | Surface roughness of Ti alloy was higher than Stst P558 |
| Montanaro et al. [40] | Orthopedic implants | Stst Böhler P558 (Ni-free), Stst AISI 316 L | Surface roughness, chemical composition | Ra values below 0.2 μm |
| Michiardi et al. [41] | Dental (orthodontics), orthopedic implants | NiTi alloy oxidized at 400°C at subatmospheric pressure, untreated NiTi, cpTi | –b | –b |
| Animal osteoblasts | ||||
| Morais et al. [42] | Implants | AISI Stst 316L | Determination of released metal ions—AAS | The concentration of metal ions released from Stst (μg/ml): Fe(III), 500; Cr(III), 122; Ni(II), 101. Diluted 103, 104, 105 times |
| Kapanen et al. [43] | Dental wares and gastrointestinal surgery | Nitinol (Ni–Ti alloy), Stst AISI 316LVM, ASTM Grade 2—pure Ti, Tisto, pure Ni | –b | –b |
| Fini et al. [44] | Dental, orthopedic implants | Stst P558, SSt, Ti6Al4V, polystyrene wells (control) | Surface roughness (laser profilometer), chemical composition | Ti6Al4V—the highest roughness values (in vivo test) |
| Cortizo et al. [45] | Orthodontic appliances | Pure metals: (1) Ag, (2) Au, (3) Pt, (4) Pd, (5) Cu, (6) Ni/Ti alloy (Nitinol), (7) FBS-DMEM (control) | Measurement of concentration of released ions—FAAS; electrochemical experiments | Anions and proteins interfered in the corrosion process—by voltammograms; fetal bovine serum (FBS) influenced electrochemical process by decrease of the oxidation rate of the metal |
| Yeung et al. [46] | Orthopedic implants | NiTi alloy implanted with (1) NiTi—not implanted, (2) NiTi–N, (3) NiTi–O, (4) control (empty well) | Chemical composition and depth profile (XPS) | Near-surface Ni content in the treated materials was reduced. PIII treatment improved the surface properties of NiTi alloys; better corrosion resistance was achieved together with the reduced released of Ni |
| Yeung et al. [47] | Orthopedic implants | NiTi alloy implanted with (1) NiTi, (2) NiTi, (3) NiTi, (4) NiTi—not implanted | Depth profile (XPS), microhardness, surface morphology (SEM), ion release (ICP-MS), corrosion resistance | Leaching of Ni and Ti was reduced by implanting |
| Wu et al. [48] | Medical implants | Ni and Ti powder fabricated into porous alloy oxidized at 6 different temperatures and untreated porous NiTi, wells without any metal disks (control) | Oxygen plasma immersion ion implantation, compression test, XPS, immersion tests—ICP-MS | Good mechanical properties and superelasticity; the quantity of nickel released from the material was lower than from the untreated samples; XPS—nickel-depleted surface layer predominantly composed of TiO2 is produced by O-PIII and was a barrier against release of nickel |
| Wu et al. [49] | Surgical implants, material for bone grafts | Ni and Ti powder fabricated into porous alloy oxidized at 6 different temperatures 300°C, 400°C, 450°C, 550°C, 600°C, 800°C for 1 h and untreated (control) | Roughness, Ni release behavior (ICP-MS), transformation temperatures, superelasticity, morphology (SEM), XPS, immersion test, DSC, and compression test | Lower Ni release, best superelasticity, austenite transition temperature below 37°C for the material fabricated at 450°C |
| Liu et al. [50] | Orthopedic implants | NiTi with the surface modified by nitrogen plasma immersion ion implantation (N-PIII) at various voltages | Chemical composition XRD; topography and roughness before and after N-PIII—AFM; immersion test (ICP-MS), SEM; three-point bending tests | Near-surface |
| Ni concentration—reduced by PIII; the surface TiN layer suppressed nickel release | ||||
| Yeung et al. [51] | Orthopedic implants | NiTi—nitrogen plasma ion implantation (N-PIII); control—untreated NiTi, Stst, Ti–6Al–4V | Chemical composition XPS, corrosion resistance—immersion tests (ICP-MS), hardness measurements; surface roughness (AFM) | The corrosion resistance and release of Ni ions were improved by ion implantation as compared with Stst and NiTi, comparable with alloy containing Ti |
| Ochsenbein et al. [52] | Orthopedic implants | Pure Ti coated by the sol–gel process, oxidized with TiO2, SiO2, Nb2O5, SiO2–TiO2, uncoated, 316 SL Stst as a positive control | FTIR, X-ray diffraction, VASE, dual-beam focused ion beam/SEM, WLI, AFM, contact angle measurement for surface energy | Physicochemical characterization of the oxide coatings showed a nanoporous structure in the TiO2 and Nb2O5 layers, the SiO2 and SiO2–TiO2 layers appeared almost smooth; the absence of organic residues; the thickness of layers was 100 nm |
| Liu et al. [53] | Orthopedic implants | NiTi with the surface modified by nitrogen plasma immersion ion implantation (N-PIII) at 0 (control), 50, 100, 200 Hz | XPS, AFM | XPS—implantation depth of nitrogen increased with higher pulsing frequencies; AFM—nanoscale surface roughness increased and surface features are changed from islands to spiky cones with higher pulsing frequencies |
aThe results are discussed in the section “Human Osteoblasts” (OB)
bNot found