Key Engineering Materials Vols. 309-311

Abstract: The surface morphology of commercially pure titanium was investigated with varying electrical waveform. Controlling of electrical pulse width is effective to change pore sizes. Longer electrical pulse width was induced, larger size of pores were generated.

Abstract: The formation of titanium oxide layer with micro and nanotube arrays on titanium substrate was investigated by grit-blasting and anodic oxidation treatment. Micro rough surface can be formed by grit-blasting and nanotube arrays can be formed by anodic oxidation. The morphology of the hybrid surface(micro and nanotube arrays surface) can be affected by the mechanical conditions (grit size, grit material, blasting pressure, nozzle tip of blasting machine, distance nozzle tip and specimen, blasting time) and electrochemical conditions (applied potential, electrolyte concentration and anodizing time) used. Such micro pore and nanotube arrays of titanium oxide can be useful for well-adhered bioactive surface layer on Ti implant metals for orthopedic and dental implants, as well as for photo catalysts and other sensor applications.

Abstract: Alkali treatment induced to form bonelike apatite layer on the surface of the anodic oxidized Ti6Al4V in 1.5 SBF. It was observed that some spherical apatite crystals were deposited on the surface of the sample for only 1 d. They gradually grew to cover the whole surface of the sample with further increasing soaking time. After 7 days of soaking in 1.5 SBF, apatite covered all the surfaces of the titanium alloys, and they packed very densely and uniformly. At the same time, large amount of new-formed apatite nuclei occurred on the first layer of apatite. The EDS and XRD results proved that all the new-formed phases were composed of apatite. Mechanism of the bioactivity of the anodic oxidized titanium alloys was related to the Ti-OH group formation, and the Ti-OH group would induce apatite formation in SBF.

Abstract: The electrochemical cathode bioactivating titanium with additive of citrate was reported. After the treatment, there was a uniform dense layer with very tiny granules on the surface of the titanium, this layer was composed of amorphous calcium phosphate-citrate (ACP-CIT) with a thickness of about 150nm. After immersion in saturated calcium phosphate solution, the morphology at different time points of the early stage was quite different. The changes of morphology showed that the citrate in amorphous calcium phosphate modulated the crystal growth.

Abstract: Grit blasting using bioactive HA and biodegradable CMP followed by acid etching has been done. HNO3 and H3PO4 were used for the etching solution by controlling the concentration and etching time to know the effect on the surface chemistry and morphology of the Ti implant. Characterization of samples was done by using SEM, EDX and surface profilometer. The contents of residues on Ti surface decreased with increasing acid concentration and etching time. It was observed that the acidic etching rate of HA grits on Ti surface was faster than that of CMP grits. And HNO3 etched more rapidly the HA and CMP grits on Ti surface, compared to H3PO4. Therefore, the surface roughness of dental implants can be controlled by having appropriate combination of acid concentration and etching time.

Abstract: Grit-blasting using bioactive HA and biodegradable CMP followed by acid etching was done. The apatite formation of prepared Ti samples was evaluated by immersion in R-SBF. And cell viability, proliferation, and differentiation were conducted using MTT assay and ALP staining. In RSBF immersion tests, non-etched HA-blasted samples showed the faster apatite-like formation than other samples. Acid etched and non-etched HA-blasted samples showed better cell viability and proliferation compared to CMP-blasted samples after 1 and 3 days. And the cell differentiation of non-etched HA-blasted samples was better compared to etched ones, and etched and non-etched CMP-blasted samples.

Abstract: The objective of this study was to evaluate the interface shear strength and the responses of osteoblast-like cells to titanium implants with a sandblasted and acid-etched surface modified by alkali and heat treatments (SLA-AH). The implants with machined and SLA surface served as controls. Each type of implant was characterized by scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis. In vitro assays were made using human osteoblast-like cell culture on different surfaces. The rectangle plates were also transcortically implanted into the proximal metaphysis of New Zealand White rabbit tibiae. After 4, 8 and 12 weeks implantation, mechanical and histological assessments were performed to evaluate biomechanical and biological behavior in vivo. By SEM examination, SLA surface combined with AH treatments revealed a macro-rough surface with finely microporous structure. The in vitro assays showed that the SLA-AH surfaces exhibited more extensive cell deposition and improved cell proliferation as compared with controls. Pull-out test demonstrated that the SLA-AH treated implants had a higher mechanical strength than the controls at all interval time after implantation. Histologically, the test implants revealed a significantly greater percentage of bone-implant contact when compared with controls. The results of this study suggest that a useful approach by combined processes could optimize implant surfaces for bone deposition and produce distinct biological surface features.

Abstract: The effects of four surface modification (acid-etching, alkaline treatment, acid-etching /alkaline treatment, and sandblasting) of commercially pure titanium (cpTi) on the early cellular responses of osteoblast-like MC3T3-E1 cells were investigated. MTT assay was used to measure the levels of cell attachment to the different surface specimens after 1-, 2-, and 3-hr cell incubation. All data were submitted to two-way analysis of variance. Cell morphology was observed by scanning electron microscopy (SEM). Results showed that initial adhesion of osteoblast-like cells was independent on the surface of cpTi modified with different method.

Abstract: Anatase films with various morphologies were formed on Ti surface through different approaches using hydrogen peroxide solutions. A porous anatase surface was found to favor apatite deposition in SBF, or in vitro bioactivity. Thicker films with wider crack gaps also showed enhanced in vitro bioactivity. However, the most predominant effect was the abundance of Ti-OH functional groups incorporated in the anatase films.