Effect of porous zirconia ceramics on proliferation and differentiation of osteoblasts / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effect of porous surface morphology of zirconia on the proliferation and differentiation of osteoblasts.@*METHODS@#According to different manufacturing and pore-forming methods, the zirconia specimens were divided into 4 groups, including milled sintering group (M-Ctrl), milled porous group (M-Porous), 3D printed sintering group (3D-Ctrl) and 3D printed porous group (3D-Porous). The surface micromorphology, surface roughness, contact angle and surface elements of specimens in each group were detected by scanning electron microscope (SEM), 3D laser microscope, contact angle measuring device and energy-dispersion X-ray analysis, respectively. MC3T3-E1 cells were cultured on 4 groups of zirconia discs. The cell morphology of MC3T3-E1 cells on zirconia discs was eva-luated on 1 and 7 days by SEM. The cell proliferation was detected on 1, 3 and 5 days by cell counting kit-8 (CCK-8). After osteogenic induction for 14 days, the relative mRNA expression of alkaline phosphatase (ALP), type Ⅰ collagen (Colla1), Runt-related transcription factor-2 (Runx2) and osteocalcin (OCN) in MC3T3-E1 cells were detected by real-time quantitative polymerase chain reaction.@*RESULTS@#The pore size [(419.72±6.99) μm] and pore depth [(560.38±8.55) μm] of 3D-Porous group were significantly larger than the pore size [(300.55±155.65) μm] and pore depth [(69.97±31.38) μm] of M-Porous group (P < 0.05). The surface of 3D-Porous group appeared with more regular round pores than that of M-Porous group. The contact angles of all the groups were less than 90°. The contact angles of 3D-Ctrl (73.83°±5.34°) and M-Porous group (72.7°±2.72°) were the largest, with no significant difference between them (P>0.05). Cells adhered inside the pores in M-Porous and 3D-Porous groups, and the proliferation activities of them were significantly higher than those of M-Ctrl and 3D-Ctrl groups after 3 and 5 days' culture (P < 0.05). After 14 days' incubation, ALP, Colla1, Runx2 and OCN mRNA expression in 3D-Porous groups were significantly lower than those of M-Ctrl and 3D-Ctrl groups (P < 0.05). Colla1, Runx2 and OCN mRNA expressions in M-Porous group were higher than those of 3D-Porous group (P < 0.05).@*CONCLUSION@#The porous surface morphology of zirconia can promote the proliferation and adhesion but inhibit the differentiation of MC3T3-E1 cells.

Biomechanical Study of Three-Dimensional Printed Titanium Root-Analogue Implant with Porous Surface / 医用生物力学

Objective To investigate biomechanical properties of personalized titanium root-analogue implants with porous surface, so as to provide theoretical basis for the design and clinical implantation of such implants. Methods Based on CT data, the personalized model of root-analogue implant with porous surface was designed by using 3-matic software, and after registering it with the mandible model, the mesh was divided and material parameters were attributed. The implant was applied with 200 N loading, and the maximum stress of the implant and the stress and strain of the bone around the implant were analyzed. An appropriate clinical case was selected and the implant was implanted immediately after tooth extraction for conducting clinical evaluation. Results The peak stress of the personalized root-analogue implant with porous surface was mainly concentrated on the interface between the solid structure and the porous structure of the implant. The maximum stresses of the solid structure and porous structure were 137.710 and 37.008 MPa, respectively, which were smaller than its yield strength. The three-dimensional (3D) printed porous root-analogue implants had good initial stability immediately after implantation, with minimal trauma and similar mechanical transmission to natural teeth. This simplified the surgical process, shortened the treatment time, and had high patient satisfaction. Conclusions The 3D printed root-analogue implant with porous surface explores a new method for immediate implantation after tooth extraction.

Structural control and characterization of hierarchically structured fibrous scaffolds / 中国修复重建外科杂志

Objective: To prepare hierarchically structured fibrous scaffolds with different morphologies, and to explore the additional dimensionality for tuning the physicochemical properties of the scaffolds and the effect of their hemocompatibility and cytocompatibility. Methods: Electrospinning poly (e-caprolactone) (PCL)/polyvinylpyrrolidone (PVP) bicomponent fibers (PCL∶PVP mass ratios were 8∶2 and 5∶5 respectively), and the surface porous fibrous scaffolds were prepared by extracting PVP components. The scaffolds were labeled PCL-P8 and PCL-P5 respectively according to the mass ratio of polymer. In addition, shish-kebab (SK) structured scaffolds with different kebab sizes were created by solution incubation method, which use electrospun PCL fibers as shish while PCL chains in solution crystallizes on the fiber surface. The PCL fibrous scaffolds with smooth surface was established as control group. The hierarchically structured fibrous scaffolds were characterized by field emission scanning electron microspore, water contact angle tests, and differential scanning calorimeter (DSC) experiments. The venous blood of New Zealand white rabbits was taken and hemolysis and coagulation tests were used to characterize the blood compatibility of the scaffolds. The proliferation of the pig iliac artery endothelial cell (PIEC) on the scaffolds was detected by cell counting kit 8 (CCK-8) method, and the biocompatibility of the scaffolds was evaluated. Results: Field emission scanning electron microscopy showed that porous morphology appeared on the surface of PCL/PVP bicomponent fibers after extracting PVP. In addition, SK structure with periodic arrangement was successfully prepared by solution induction, and the longer the crystallization time, the larger the lamellar size and periodic distance. The contact angle and DSC measurements showed that when compared with smooth PCL fiber scaffolds, the crystallinity of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds increased, while the hydrophobicity of PCL-SK fibrous scaffolds increased, but the hydrophobicity of PCL porous scaffolds did not change significantly. The hemolysis test showed that the hemolysis rate of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds was higher than that of PCL fibrous scaffolds. According to American Society of Materials and Tests (ASTM) F756-08 standard, all scaffolds were non-hemolytic materials and were suitable for blood contact materials. Coagulation test showed that the coagulation index of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds was higher than that of PCL fibrous scaffolds at 5 and 10 minutes of culture. CCK-8 assay showed that both hierarchically structured fibrous scaffolds were more conducive to PIEC proliferation than PCL fibrous scaffold. Conclusion: Based on electrospinning technology, solution-induced and blend phase separation methods can be used to construct multi-scale fiber scaffolds with different morphologies, which can not only regulate the surface physicochemical properties of the scaffolds, but also have good blood compatibility and biocompatibility. The hierarchically structured fibrous scaffolds have high application potential in the field of tissue engineering.

An experimental study on the osseointegration of the ti-6al-4v bead coating implants

Microstructural Change of Porous Surface Implant conditioned with Tetracycline-hydrochloride / 대한치주과학회지

Mechanical and chemical methods are the two ways to treat the implant surfaces. By using mechanical method, it is difficult to eliminate bacteria and by-products from the rough implant surface and it can also cause the structural change to the implant surface. Therefore, chemical method is widely used in order to preserve and detoxicate the implant surface more effectively. The purpose of this study is to evaluate the effect of tetracylcline-hydrochloride(TC-HCl) on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and porous surface were used in this study. Implant surface was rubbed with sponge soaked in 50mg/ml TC-HCl solution for 1/2 min., 1 min., 1 1/2 min., 2 min., and 2 1/2min. respectively in the test group and with no treatment in the control group. Then, specimens were processed for scanning electron microscopic observation. 1. Both test and control group showed a few shallow grooves and ridges in pure titanium machined surface implants. There were not significant differences between two groups. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. Subsequently, the acid-etching process created the micro roughness, which thus was superimposed on the macro roughness. Irrespective of the application time of 50mg/ml TC-HCl solution, in general, test specimens were similar to control. 3. In the porous surfaces, the control specimen showed spherical particles of titanium alloy and its surface have a few shallow ridges. The roughness of surfaces conditioned with tetracycline-HCl was lessened and seen crater-like irregular surfaces relative to the application time. In conclusion, pure titanium machined surfaces and SLA surfaces weren't changed irrespective of the application time of tetracycline-HCl solution. But the porous surfaces conditioned with tetracycline-HCl solution began to be slightly changed from 2 min. This results are expected to be applied to the regenerative procedures for peri-implantitis treatment.