OBJECTIVETo study the bonding characteristic of Titanium and RG experiment porcelain.

METHODS5 specimens with a size of 10 mm x 5 mm x 1.4 mm were cast from pure titanium. Then 1 mm of RG experiment opaque and body porcelain were fused on the surface of the titanium specimens. The interface of titanium and porcelain was analyzed with a scanning electron microscope with energy-despersive spectrometry; 6 metal specimens with the size of 25 mm x 3 mm x 0.5 mm were cast from Ni-Cr alloy and a uniform thickness of 1 mm of VMK 99 porcelain was veneered on the central area of 8 mm x 3 mm 18 metal specimens as the same size were cast from pure titanium. The uniform thickness of 1 mm of VITA TITANKERAMIK porcelain, of Noritake super porcelain Ti-22 and of RG experiment porcelain were veneered on every 6 specimens respectively in the central area of 8 mm x 3 mm. The specimens were subjected to a three-point bending test on a load-test machine with a span of 20 mm, then the failure loads were recorded and statistically analysised. The RG porcelain/titanium crown was fabricated by fusing RG opaque porcelain and body porcelain to cast titanium substrate crown.

RESULTSThe SEM results show no porosity and crackle were found in the interface. The energy-dispersive spectrometry show that there are Si, Ti and O in the 1 micro m layer between porcelain and titanium, which suggesting titanium and experiment porcelain bonding well. The three point test showed the fracture force for the combinations of titanium/VITA TITANKERAMIK porcelain, titanium/Noritake super porcelain Ti-22 and titanium/RG experiment porcelain were (7.233 +/- 2.539) N, (5.533 +/- 1.199) N and (6.316 +/- 1.433) N respectively. There were not statistically significant differences among them (t test, P < 0.01). The fracture force for the Ni-Cr alloy/VMK99 porcelain combination (12.733 +/- 3.297) N was significantly greater than those of the cast titanium/porcelain (t test, P > 0.05). The crown was translucent with no crack.

CONCLUSIONRG porcelain is well compatible with titanium.

Amides can be obtained in good to excellent yield by Sm/TiCl(4) mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.
Azo Compounds ; chemistry ; Chlorine Compounds ; chemistry ; Combinatorial Chemistry Techniques ; methods ; Halogens ; chemistry ; Samarium ; chemistry ; Titanium ; chemistry

The dissolution of nickel from nitinol alloy under different extraction conditions was investigated when biological tests of nitinol medical devices were carried out. It discussed the equivalence of these extraction conditions and found the best extraction conditions. In the experiment, two brands of nitinol were chosen and extracted under different extraction conditions according to GB/T 16886-12. Plasma emission spectrometer was used to analyse the concentration of nickel in extract liquid. The results show that there is no equivalence among these extraction conditions for nitinol materials. And it is suggested that (37 +/- 1) degree C, (72 +/- 2) h could be used as normal extraction condition and (70 +/- 2) degrees C, (24 +/- 2) h as accelerated extraction condition.
Alloys ; chemistry ; Biocompatible Materials ; Materials Testing ; Nickel ; chemistry ; Temperature ; Titanium

BACKGROUNDIn order to bind or fix bioactive materials directly to the surface of a Ti implant, the prior binding process of functional groups (FGs, -COOH and -OH) to the implant surface is necessary. Conventional binding processes are so high-cost and complex, so it is essential to find a simple and effective procedure for Ti-FG binding.

METHODSVarious electrolyte compositions and electrochemical processing were adopted in this study to develop a relatively simple and effective Ti-FG binding process. The ability of Ti-FG binding and calcium (Ca)/phosphorous (P) absorption and corrosion resistance were evaluated according to various titanium surface treatment in electrolyte involving -COOH and -OH ion by using X ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM) and potentiodynamic scan method respectively.

RESULTSIn cases of -COOH, the anodic oxidation process (AN) showed an effective binding ability between -COOH and Ti surface. On the other hand, in cases of -OH, there were no significant differences in the result between the conditions used. In regard to the absorption of Ca and P on Ti surface, there was a minimal amount of Ca absorbed but no P was absorbed. The anodic oxidation series showed homogenous corrosion, whereas the electrolyte immersion (EL) series showed unstable corrosion. Although EL-OH showed a novel corrosion potential, the EL-COOH series showed good corrosion resistance over the anodic potential range.

CONCLUSIONSThe ability of binding between FG and the Ti surface and Ca/P absorption were strongly associated with the surface potential (ζ potential), which was dependent on the pH of the electrolyte. Accordingly, in order to achieve the effective absorption of various FGs on the Ti surface, it is needed to develop the combination process in addition to the electric affinity, relation with the ζ potential.

This paper reviews the progress in biochemical design and modification for the surfaces of titanium implants in recent years, the emphasis being laid on the introduction of the surface molecular construction, self-assembly technique and its application in biomedical materials.
Biocompatible Materials ; chemistry ; Prostheses and Implants ; Surface Properties ; Titanium ; chemistry

Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination.
Acetic Acid ; chemistry ; Adsorption ; Amino Acids ; chemistry ; Drug Interactions ; Nanotubes ; chemistry ; Oxides ; chemistry ; Titanium ; chemistry

Exposed to neutron flow, the phosphorus implanted TiNi alloy gets radioactive. This radioactive material is used in vascular stent for prevention and cure of restenosis. Phosphorus implantation is carried out in a plasma immerged ion implantation system, and the dose of phosphorus implantation is in the range of 2-10 x 10(17) cm-2. After ion implantation, the alloy is exposed to the slow neutron flow in a nuclear reactor, the dose of the slow neutron is 1.39-5.88 x 10(19) n/cm2. The radioactivity of the TiNi alloy was measured by liquid scintillation spectrometry and radio-chromic-film dosimetry. The result shows that whether the phosphorus is implanted or not, the TiNi alloy comes to be radioactive after exposure to neutron flow. Just after neutron irradiation, the radiation dose of phosphorus implanted TiNi alloy is about one hundred times higher than that of un-phosphorus implanted TiNi alloy. The radiation difference between phosphorus and un-phosphorus implanted alloy decreases as time elapses. Within three months after neutron irradiation, the average half-decay period of phosphorus implanted TiNi alloy is about 62 days. The radiation ray penetration of phosphorus implanted TiNi alloy is deeper than that of pure 32P; this is of benefit to making radiation uniformity between stent struts and reducing radiation grads beyond the edge of stent.
Alloys ; chemistry ; Blood Vessel Prosthesis ; Nickel ; chemistry ; Phosphorus Radioisotopes ; chemistry ; Radiation Dosage ; Titanium ; chemistry

The corrosion rates of TiNi, CoCrNiW and CoCrNiMo were measured in Tyrode's solution with potentiodynamic linear polarization, fore-point weak polarization, Cao Chunan weak polarization, transient linear polarization and atomic absorption spectroscopy. Results indicated that corrosion rates of these three alloys were very low due to their excellent corrosion resistance and the corrosion resistance of CoCrNiMo was the best. Corrosion rates of TiNi, CoCrNiW and CoCrNiMo were 0.691, 0.0595, 0.0490 micron/a and 0.0528, 0.0383, 0.0387 micron/a, respectively. The results measured by the first three methods were about ten times of those by the latter two methods, this was related to the applicability of each method and the alloy surface state. Transient linear polarization technique can determine low corrosion rate conveniently and quickly. Atomic absorption spectroscopy method, determining directly the concentration of ion in solution, and thus provide reference for material biocompatibility. And these two methods are properly used in measuring corrosion rates for biomedical materials.
Biocompatible Materials ; chemistry ; Cobalt ; chemistry ; Corrosion ; Materials Testing ; methods ; Nickel ; chemistry ; Spectrophotometry, Atomic ; Titanium ; chemistry

SO(4)(2-)/TiO(2)-La(2)O(3), a novel solid superacid, was prepared and its catalytic activities at different synthetic conditions are discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions have also been found, mole ratio of n(La(3+)):n(Ti(4+)) is 1:34, the soaked consistency of H(2)SO(4) is 0.8 mol/L, the soaked time of H(2)SO(4) is 24 h, the calcining temperature is 480 degrees C, the calcining time is 3 h. Then it was applied in the catalytic synthesis of ten important ketals and acetals as catalyst and revealed high catalytic activity. Under these conditions on which the molar ratio of aldehyde/ketone to glycol is 1:1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 41.4%-95.8%.
Acetylation ; Acids ; chemistry ; Catalysis ; Hydrogen-Ion Concentration ; Ketones ; chemistry ; Lanthanum ; chemistry ; Oxides ; chemistry ; Powders ; Sulfates ; chemistry ; Titanium ; chemistry

Recently, porous titanium granules (PTGs) have been indicated for the preservation of the dimensions of post-extraction sockets, as a filler in sinus lift procedures and for the treatment of peri-implant and periodontal defects, based on the osteoconductivity and dimensional stability of the titanium granules. However, there is a lack of information regarding the use of this material in larger defects and in conjunction with membranes. The objective of this study is to test the behavior of PTGs used to fill critical size defects in rabbit tibiae, with and without membranes. Critical defects were created in both tibiae of rabbits, divided randomly into three groups: Group A (defect filled with PTG), Group B (defect filled with PTG+collagen membrane) and a control group (empty defect). After six weeks, histomorphometric analysis was performed. The results showed more defect closures at the cortical area (87.37%±2.2%) and more bone formation at the marrow area (57.6%±1.3%) in Group B, in comparison with the other groups (P<0.05); the use of membranes improved the material stability expressed as more percentages of the original material when membranes were used (P<0.05). Finally, inflammatory reactions were observed when the granules were not protected by membranes. In spite of the limitations of this animal study, it may be concluded that PTG particles are osteoconductive and allow bone growth. The PTG particles must be covered by a membrane, especially when grafting larger defects, in order to control particle migration, promote clot stabilization and separate the PTG graft from undesired soft tissue cells.
Animals ; Male ; Membranes, Artificial ; Rabbits ; Tibia ; abnormalities ; Titanium ; chemistry