Table 1.
Description of the 16 studies that, both in vivo and in vitro, evaluate the mechanical and regenerative properties of the different materials used to manufacture 3D scaffolds *.
| Author/Year | Material | Material and Methods | Fabrication Technique | Results |
|---|---|---|---|---|
| Eshraghi S. 2010 [15] |
Polymer. PCL | 3 scaffolds (1D, 2D, and 3D) with different geometries and orthogonal pores, each one more porous than the previous one. | SLS | The structures designed for load bearing locations were accurate with respect to the digital design, and compressive strength was significantly higher in the 1D scaffolds, and the same in the 2D and 3D scaffolds (10.0 ± 0.62 and 0.60 MPa respectively). |
| Lee SJ. 2019 [16] |
Polymer. PCl, PCLD (PCL with polydopamine) and PCLDB (BFP1: bone-forming peptide) | In vitro with human mesenchymal cells and in vivo with New Zealand rabbits. | FFF | Surface treatment with Dopamine and BFP1 considerably increases osteogenesis and angiogenesis. |
| Xu H. 2010 [17] |
Synthetic polymers. PLA/PGA |
Eight male Beagle dogs were used. | Lost-wax | The scaffolds were compared with the initial models and proved to be very accurate. The bioblocks demonstrated high biocompatibility when incubated in vitro with mesenchymal bone cells. |
| Gendviliene I. 2020 [18] |
Polymer and composite material. PLA and PLA/HA | Three groups of scaffolds (n = 22 each group) were compared, 2 pure PLA with different printers and one PLA/HA. | FFF | Pure PLA frames made with the Pharaoh XD20 printer showed greater accuracy compared to the Ultimaker Original 3D printer, although the highest accuracy was achieved with PLA/HA scaffolds. |
| Lin YH. 2017 [19] |
Composite material. CaSi + PCL | Human mesenchymal cells were used for the in vitro study. | DIW | By adding CaSi to the PCL, compressive strength (5.8 MPa) increased, as did hydrophilia and osteogenic differentiation and angiogenesis. |
| Roh HS. 2016 [20] |
Composite material. PCL + HA + MgO | The scaffolds were treated with oxygen and nitrogen plasma. They were analyzed in vitro with pre-osteoblastic cells. | FFF | The addition of HA and MgO facilitated the initial adhesion, proliferation and differentiation of the cells. The treatment with plasma increased hydrophilicity, enhancing the bioactivity of the scaffolds. |
| Pae HC. 2018 [21] |
Polymer and composite material. PCL + β-TCP. | Ten rabbits with 4 circular calvarial defects of 8 mm each: Control/PCL/PCL + β-TCP/PCL + β-TCP + membrane. | FFF | Compressive strength resistance was higher in PCL (46.7 ± 1.7 N/mm) than in PCL + β-TCP (35.7 ± 3.1 N/mm). PCL/β-TCP + M showed the highest total and new bone volume at 8 weeks and only bioblocks with β-TCP contained new bone (hydrophilicity and conductivity increased) |
| Kim BS 2018 [22] |
Bioceramics. HA and HA + PCL with BMP-2-loaded nanoparticles (NP) | Four rabbits were used with 3 calvarial defects of 6 mm: control/HA/HA + PCL + NP. | 3D printing | The PCL-NP coating was useful to incorporate BMP-2/NP to improve bone regeneration, and to improve compressive strength by the PCL (5.10 ± 0.49 MPa). |
| Miranda P. 2006 [23] |
Bioceramics. β-TCP | Structures with different inks, geometries, and nozzle diameters, sintered at different temperatures (1250 °C–1550 °C) depending on the composition of the powder. | DIW. Robocasting | Powders with reduced particle size and a low-specificity surface area were more suitable for manufacturing through robocasting. To avoid TCP transition (from beta to alpha): calcium deficient powders and sintering temperatures below 1125 °C. |
| Zhou Z. 2014 [24] |
Bioceramics. Calcium phosphate mixed with calcium sulphate (CaSO4) |
The effects of particle size, the CaP/CaSO4 ratio and the type of CaP powder (HA/TCP) were measured. | 3D printing | Best result with a powder size of 30–110 microns and a higher proportion of CaP with respect to CaSO4 (25/75). HA performed better than b-TCP: good print accuracy and compressive strength for no-load defects (1.98 MPa). |
| Guda T. 2012 [25] |
Bioceramics. HA with different porosities and ratio between cortical and trabecular layer. |
Six cylindrical samples of each type of 8 mm in diameter and 16 in length | Lost-wax | Although the elastic module did resemble that of human bone, the compressive strength was much lower than that of the trabecular bone. It was also shown that the macropore size of the core does not influence the mechanical aspect. |
| Eqtesadi S. 2014 [26] |
Bioceramics. Bioactive glass 45S5 | Compared the mechanical properties of bioglass 45S5 obtained with robocasting against other techniques. | DIW. Robocasting |
Compressive strength = 2–13 MPa Robocasting is the best option for 45S5 glass structures with the necessary mechanical properties for their clinical application. |
| H. Shao. 2018 [27] |
Bioceramics. Typical porous bioceramics were compared with wollastonite with Mg-10% (CSiMg10). |
Alveolar defects were created in the jaws of 32 rabbits. They were sacrificed at 8 and 16 weeks. A total of 64 samples were obtained. | DIW | In vitro, CSiMg10 scaffolds were placed in a liquid buffer and showed a slight dissolution, moderate weight loss (7%) and hardly any reduction in bending strength (31 MPa). In vivo, they revealed a significantly higher osteogenic capacity than the TCP, CSi and Bred scaffolds after 16 weeks. |
| ShaoH. 2017 [28] |
Bioceramics. Pure calcium silicate (CSi) and CSiMg6. |
Structures of different thicknesses by printing in one or double layer and sintering in 1/2 steps. Twenty-four rabbits were used for the in vivo study. | FFF | CSiMg6 and two-step sintering showed the best compression and bending strength figures (104/18 MPa). Single layer structures had greater bone formation in the short term (4 weeks), and double layer in the long term (8–12 weeks). The CSi showed greater regeneration. In the CSiMg6, regeneration was also acceptable, with the advantage of high fracture resistance. |
| Lee. YK. 2008 [29] |
Bioceramics. Calcium phosphate glass with a significantly lower Ca/P ratio than typical calcium phosphates. |
For the in vivo study, the following were used:
|
Lost-wax using polyurethane ester cross-linked sponges. | In vitro, the degree of dissolution and the calcification and mineralization were improved by Calcium phosphate glass. In vivo in rats and dogs, a significant improvement in bone and cement formations was observed with Calcium phosphate glass. |
| Tarafder S. 2013 [30] |
Bioceramics. Bioblocks from β-TCP pure and doped were compared with Sr-Mg. |
Twenty-four male rats in which 20 bioblocks of β-TCP pure (Control) and 20 doped with Sr-Mg (study) were placed. | 3D printing | The compressive strength of the study was higher than that of the control (12.01 ± 1.56 MPa and 10.95 ± 1.28 MPa respectively). At 12–16 weeks, the bone formed in the control was less mineralized. At 16 weeks, it was mineralized in both bioblocks. Biological performance in vivo was improved by the addition of SrO and MgO. |
* Visit the acronyms section at the end of the paper for the description of the material and/or technique mentioned in this table.