SEARCH · PubMed Health

Results for “Ti implants”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources

PubMed2006

Surface and elemental alterations of dental alloys induced by electro discharge machining (EDM).

OBJECTIVES: To evaluate the surface and elemental alterations induced by electro discharge machining (EDM) on the surface of dental cast alloys used for the fabrication of implant retained meso- and super-structures. METHODS: A completed cast model of an arch that received dental implants was used for the preparation of six wax patterns which were divided into three groups (Au, Co and Ti). The wax patterns of the Au and Co groups were invested with conventional phosphate-bonded silica-based investment material and the Ti group with magnesia-based investment material. The investment rings of the Au and Co groups were cast with an Au-Ag alloy (Stabilor G) and a Co-Cr base alloy (Okta C), respectively, while the investment rings of group Ti were cast with cp Ti (Biotan). One casting of each group was subjected to electro discharge machining (EDM); the other was conventionally ground and polished. The surface morphology and the elemental compositions of conventionally and EDM-finished surfaces were studied by SEM/X-ray EDS analysis. Six spectra were collected from each surface employing the area scan mode and the mean value of each element between conventionally and EDM-finished surfaces was statistically analyzed by t-test (a=0.05). Then the specimens of each group were cut perpendicular to their longitudinal axis and after metallographic grinding and polishing the cross-sections studied under the SEM. RESULTS: The EDM surfaces showed a significant increase in C due to the decomposition of the dielectric fluid during spark erosion. Moreover, a significant Cu uptake was noted on these surfaces from the decomposition of the Cu electrodes used for EDM. Cross-sectional analysis showed that all alloys developed a superficial zone (recast layer) varying from 2 microm for Au-Ag to 10 microm for Co-Cr alloy. SIGNIFICANCE: The elemental composition of dental alloy surfaces is significantly altered after EDM treatment.

Carbon↗

PubMed2003

Chemically patterned, metal oxide based surfaces produced by photolithographic techniques for studying protein- and cell-surface interactions I: Microfabrication and surface characterization.

Chemical patterns on smooth wafer substrates comprising areas with two different metals have been produced by vacuum metal deposition and photolithographic techniques. The combination of metals has been chosen from the series titanium (Ti), aluminium (Al), vanadium (V) and niobium (Nb), producing patterns (dots and stripes with dimensions of 50, 100 and 150 micrometer) with one of the metals as the background and with the second metal (foreground pattern) deposited on the background metal. The structure and chemical composition of the patterned surfaces were evaluated by scanning electron microscopy, X-ray photoelectron spectroscopy and imaging time-of-flight secondary-ion mass spectrometry. The surfaces proved to be geometrically well defined with the expected surface-chemical composition, i.e. a surface oxide (passive) film essentially composed of TiO(2),Al(2)O(3),V(2)O(5), or Nb(2)O(5). Ti/Ti patterned surfaces were produced as controls and found to show no chemical composition contrast. The surface roughness of the pattern was greater than that of the background by a factor of 2-3, but was still extremely smooth with Ra<2nm. The patterns serve as model surfaces for studying in vitro the behaviour of cells as well as the adsorption of serum proteins on different metal oxides, which will be reported in a companion paper. These surfaces can be used to compare and contrast the response of osteoblasts to Ti and other alloy components, such as Al, V, or Nb, which are used in load-bearing medical implants.

Aluminum↗

PubMed1997

Complex N-glycans in Mgat1 null preimplantation embryos arise from maternal Mgat1 RNA.

Mice with a null mutation in the Mgat1 gene lack N-acetyl-glucosaminyltransferase I (GlcNAc-TI; EC 2.4.1.101), and die at mid-gestation. This result suggested that development of Mgat1-/- blastocysts and their implantation could occur in the absence of complex and hybrid N-glycans. However, inner cell mass of all blastocysts from several Mgat1 +/- heterozygous crosses bind the lectin E-PHA, indicating that Mgat1 null mutant blastocysts are able to synthesize complex N-glycans (Campbell et al., (1995) Glycobiology, 5, 535-543). In order to directly test this hypothesis, Mgat1-/- blastocysts were positively identified by polymerase chain reaction (PCR) of genomic DNA. Reverse transcriptase PCR (RT-PCR) of RNA isolated from the same blastocysts, and restriction analysis of the PCR products, revealed that Mgat1 null blastocysts contained Mgat1 RNA derived from the wild-type Mgat1 gene. Consistent with this, all 3.5 day blastocysts from five heterozygous crosses bound the lectin L-PHA, a lectin previously shown not to bind to E8.5 or E9.5 Mgat1-/- embryos that lack complex N-glycans (Ioffe and Stanley (1994) Proc. Natl. Acad. Sci., USA, 91, 728-732). Blastocysts of 4.5 days postcoitum (dpc) obtained by culturing 3.5 dpc blastocysts also bound L-PHA. However, mutant embryos that did not bind L-PHA were present among progeny from E5.5 onward. Therefore, the effects of the Mgat1 null mutation are not operative until sometime between implantation and E5.5, due to the continued presence of maternally derived Mgat1 mRNA in preimplantation embryos.

Animals↗

PubMed1990

Semiconductive properties of passivated titanium and titanium based hard coatings on metals for implants--an experimental approach.

Titanium is used in the field of dental implants on account of the fact that they are integrated into body tissue virtually reaction-free. This integration is made possible by the passivated layers which form within the body electrolyte, and which can be described in the terms of a semiconductive solid body. A prerequisite, however, is the prevention of relative movement between the implant and the tissue so that the passivated layer is not destroyed. The low resistance to shearing, and the oxide stoichiometry--which under in vivo conditions cannot be influenced--on repassivation following mechanical destruction strongly suggest that, during fabrication, implants should be provided with wear-resistant coatings having defined solid state properties which are similar to those of electrochemically passivated titanium surfaces. In the clinical test are already employed, a (Ti,Nb)ON- and a (Ti,Zr)O-coating on titanium and TiAl5Fe2.5. One of the most important parameters for the solid body-physical description of semiconductive hard coatings is the energy gap between conduction and valence band of the electronic structure, which are determinative for the physical-chemical behaviour of the implant surface within the body. The contribution describes the experimental procedure and the results of determinations of the energy gap at singularities in the Brillouin zone for titanium, the titanium alloys in clinical use, and some hard coatings in clinical test. The experimental method of choice for surfaces in contact with aqueous electrolytes is the electroreflectance spectroscopy.

Alloys↗

PubMed1983

Cellular responses to implant materials: biological, physical and chemical factors.

Adhesion of bone and epithelial cells to the dental implant are vital to its retention in alveolar bone and to the prevention of infection via its 'gingival' margin. Studies of cytotoxicity, tissue irritability and carcinogenicity of implantable polymers, metals and ceramics and of tissue adhesion to them have been carried out in tissue culture and in animal experiments. The more similar the polymeric materials are chemically to living tissue the more easily are they dissolved and digested in the host. Therefore, implant materials having a molecular structure similar to protein or polysaccharide, e.g. Nylon, cannot be expected to function. On the other hand, silicones, polyethylene and Teflon (polytetrafluroethylene), which have molecular structures completely different from living substances, are generally more stable in the tissues. However, these polymers are hydrophobic and have little adhesion to living cells in spite of their high stability. They are not, therefore, suitable materials for the construction of implants. Studies on antithrombotic polymers have demonstrated the possibility of creating implantable polymers which have high stability as well as strong adhesion to the surrounding tissues. These properties may be conferred by grafting a hydrophilic polymer on to the surface of a hydrophobic polymer. Of the metals, Ti, Zr and Ta are fairly stable in living tissue, and allow cells to adhere strongly. Alloys of Co-Cr-Mo, Fe-Ni-Cr-Mo, Ti-Al-V, Ti-Mo, Ti-Pd and Ti-Pt deserve to be better evaluated because they are low in density, have high mechanical strength, stability and corrosion resistance in living tissue, and there is direct adhesion to the surrounding tissues. Biodegradable or bioactive ceramics which induce bone formation around the implant do not have sufficient mechanical strength. Implant ceramics have to be stable, e.g. crystal alumina, vitreous carbon, synthetic hydroxypatite and silicon nitrate. These exhibit high biocompatibility and excellent adhesion to tissue. Single crystal sapphire ceramics with high mechanical strength permit the delicate designs required for implants. Success with dental implants may depend upon combining the rigid retention of porous stable alloys or ceramics of suitable Young's modulus with a stress absorbing superstructure. A further development to be expected is the appearance of composite and polyphase materials which have tissue adhesiveness, stability in living tissues and various degrees of Young's modulus.

Alveolar Process↗

PubMed2005

Corrosion resistance and biocompatibility of a new porous surface for titanium implants.

Alterations of the commercially pure titanium (cpTi) surface may be undertaken to improve its biological properties. The aim of this study was to investigate the biocompatibility of cpTi when submitted to a new, porous titanium, surface treatment (porous Ti). Five types of surface treatments, namely sintered microspheres porous titanium (porous Ti), titanium plasma spray (TPS), hydroxyapatite (HA), sandblasted and acid etched (SBAE), and resorbable blast medium, sandblasted with hydroxyapatite (RBM) were made. In the experimental methods, the corrosion potentials were measured over time, and then a linear sweep voltammetric analysis measured the polarization resistances and corrosion currents. For biocompatibility evaluation, MG63 osteoblast-like cells were used. Cell morphology, cell proliferation, total protein content, and alkaline phosphatase (ALP) activity were evaluated after 2 h, and after 2, 4 and 7 d. Porous Ti and SBAE showed a better corrosion resistance, with a weak corrosion current and a high polarization resistance, than the other surfaces. Cell attachment, cell morphology, cell proliferation, and ALP synthesis were influenced by the surface treatments, with a significant increase observed of the activity of osteoblast cells on the porous coating (porous Ti). Based on these results, it is suggested that the porous Ti surface has a significantly better biocompatibility than the other surface treatments and an excellent electrochemical performance.

Analysis of Variance↗

PubMed2004

Comparison of the mechanical properties of 2 prosthetic mini-implants.

Two prosthetic mini-implants (MTI and MDI), which have very similar shapes, are widely used. In this investigation, the mechanical and physical properties of 2 prosthetic mini-implants were investigated. The flexural properties were measured with a universal testing machine. The surface image was observed by SEM with EDX. X-ray analyses were performed. The maximum strength and proportion limit for the different implants differed significantly (P <0.01); however, elastic modulus did not differ significantly (P >0.01). Although the surface of the MTI was smooth, the MDI had a rough surface. The elemental analysis detected titanium (Ti) in the MTI, and Ti, aluminum, and vanadium in the MDI. From the x-ray diffraction pattern, the MTI, which is composed of pure titanium, had a narrow, sharp Ti (syn) peak, whereas the corresponding peak for the MDI was small and broad. Although the 2 devices have similar shapes and dimensions, their surfaces and mechanical properties differ greatly. MTI is easy to remove and wrought in clinical use, and MDI is excellent in flexural properties compared with MTI. (Implant Dent 2004;13:251-256)

Aluminum↗

PubMed1998

Response of MG63 osteoblast-like cells to titanium and titanium alloy is dependent on surface roughness and composition.

The success of an implant is determined by its integration into the tissue surrounding the biomaterial. Surface roughness and composition are considered to influence the properties of adherent cells. The aim of this study was to determine the effect of chemical composition and surface roughness of commercially pure titanium (Ti) and Ti-6A1-4V alloy (Ti-A) on MG63 osteoblast-like cells. Unalloyed and alloyed Ti disks were machined and either fine-polished or wet-ground, resulting in smooth (S) and rough (R) finishes, respectively. Standard tissue culture plastic was used as a control. Surface topography and profile were evaluated by cold field emission scanning electron microscopy and profilometry, while chemical composition was determined using Auger electron spectroscopy and Fourier transform infrared spectroscopy. The effect on the cells was evaluated 24 h postconfluence by measuring cell number, [3H]-thymidine incorporation into DNA, cell and cell layer alkaline phosphatase specific activity (ALPase), osteocalcin and collagen production, [35S]-sulfate incorporation into proteoglycan, and prostaglandin E2 (PGE2) and transforming growth factor-beta (TGF-beta) production. When compared to plastic, the number of cells was reduced on the pure Ti surfaces, while it was equivalent on the Ti-A surfaces; [3H]-thymidine incorporation was reduced on all surfaces. The stimulatory effect of surface roughness on ALPase in isolated cells and the cell layer was more pronounced on the rougher surfaces, with enzyme activity on Ti-R being greater than on Ti-A-R. Osteocalcin production was increased only on the Ti-R surface. Collagen production was decreased on Ti surfaces except Ti-R; [35S]-sulfate incorporation was reduced on all surfaces. Surface roughness affected local factor production (TGF-beta, PGE2). The stimulatory effect of the rougher surfaces on PGE2 and TGF-beta was greater on Ti than Ti-A. In summary, cell proliferation, differentiation, protein synthesis and local factor production were affected by surface roughness and composition. Enhanced differentiation of cells grown on rough vs. smooth surfaces for both Ti and Ti-A surfaces was indicated by decreased proliferation and increased ALPase and osteocalcin production. Local factor production was also enhanced on rough surfaces, supporting the contention that these cells are more differentiated. Surface composition also played a role in cell differentiation, since cells cultured on Ti-R surfaces produced more ALPase than those cultured on Ti-A-R. While it is still unknown which material properties induce which cellular responses, this study suggests that surface roughness and composition may play a major role and that the best design for an orthopaedic implant is a pure titanium surface with a rough microtopography.

Alkaline Phosphatase↗

PubMed2002

Long-term results of guided tissue regeneration therapy with non-resorbable and bioabsorbable barriers. II. A case series of infrabony defects.

BACKGROUND: The aim of this 5-year follow-up case series was to clinically and radiographically evaluate the long-term results after guided tissue regeneration (GTR) therapy of infrabony defects using non-resorbable and bioabsorbable barriers. METHODS: In 12 patients with advanced chronic periodontitis 12 pairs of contralateral infrabony defects were treated. Within each patient one defect received a non-resorbable (expanded polytetrafluoroethylene [ePTFE]; control: C) and the other a bioabsorbable (polyglactin 910; test: T) barrier by random assignment. At baseline and at 6 and 60 +/- 3 months after surgery clinical parameters and standardized radiographs were obtained. Gain of bone density within infrabony defects was assessed using subtraction radiography. RESULTS: Eight of 12 patients were available for the 60-month reexaminations. Six and 60 +/- 3 months after GTR therapy statistically significant (P < 0.05) vertical attachment (CAL-V) gain was observed in both groups (C6:2.6 +/- 1.4 mm; C60: 1.6 +/- 1.5 mm; T6:3.0+/- 1.7 mm; T60: 3.0 +/- 0.7mm). However at 60 months, 2 infrabony defects in the control group had lost all the attachment that had been gained 6 months after therapy and a clinically relevant but statistically in significant mean CAL-V loss of 1.0 +/- 2.1 mm was observed from 6 to 60 months. The case series failed to show statistically significant differences between test and control regarding CAL-V gain 60 months after surgery. Also subtraction analysis failed to reveal statistically significant differences regarding density gain between both groups 6 and 60 months postsurgically (C6: 26.4 +/- 54.2; C60 62.8 +/- 112.7; T6: 68.7 +/- 72.8; T60. 84.1 +/- 83.6). CONCLUSIONS: CAL-V gain achieved after GTR therapy in infrabony defects using both non-resorbable and bioabsorbable barriers was quite stable after 5 years in 14 of 16 defects.

Absorbable Implants↗

PubMedDate not supplied

Effect of titanium surface texture on the cell-biomaterial interface.

To improve the in vivo performance of engineered implants, this study examines the independent effects of surface chemistry and topography on fibroblast morphology and density in vitro. Titanium (Ti) was sputter-coated onto smooth and microtextured polyethylene terephthalate (PET). Test specimens were evaluated in 24-h, fibroblast cultures and assessed with scanning electron microscopy (SEM) for cellular morphology and density. Fibroblast density increased, as the Ti film thickness increased. The fibroblasts exhibited contact guidance on the textured test specimens. The greatest cellular density was found on the Ti-coated, textured test specimens. In conclusion, Ti and surface texture appeared to strongly influence fibroblast density and morphology as compared to PET and smooth surfaces.

Animals↗

PubMed1984

A micro-computer program package for the computation of intraocular lens powers.

An accurate micro-computer software package has been designed to assist in the calculation of IOL powers. This program set should be able to be used on any Z80 computer with the CPM operating system. It accepts measurement data, calculates the implant powers and their estimated postoperative refractions, using the same formulas as the Binkhorst IOL Power Module used in the TI- 58C programmable calculator. The advantages are that the method of entry of data helps to eliminate the clerical errors such as number transposition and impossible value entry. The program also allows for the storage of the patient information in a disc file for future use. This can speed the search for a patient's records and help to increase the efficiency of the office. The program can be executed in much less time and with greater accuracy and legibility than is possible with the TI- 58C programs.

Cell Count↗

PubMed1999

Toxicity measurement of orthopedic implant alloy degradation products using a bioluminescent bacterial assay.

The toxicity of aqueous metal solutions representative of ionic degradation products from orthopedic implant alloys was determined using a bacterial bioluminescence assay, Microtox. The toxicity of forms of the individual elements released from ASTM F75 Co-Cr-Mo (Co-Cr-Mo), F138 316L stainless steel (316L), and F136 Ti-6Al-4V (Ti-6Al-4V) was first determined, and a mathematical model was developed to predict the toxicity of mixtures of these ions. Aqueous metal solutions were then mixed according to the proportions of the ions found in these alloys, and their toxicity was measured with Microtox. Mixture behavior was classified as synergistic, antagonistic, or additive by comparing measured toxicity to predicted toxicity. Since relating these tests to actual implant corrosion processes can be confounded by selective leaching, the predicted and measured toxicity of aqueous metal solutions mixed according to proportions representative of selective leaching were next determined, and the mixture behaviors were classified as before. The most toxic individual alloying elements were found to be hexavalent Cr, Ni, and Co, in that order: a finding in accord with prior biocompatibility research. Co-Cr-Mo was found to be the most toxic alloy mixture of both those combined according to alloy composition and those combined to reflect selective leaching. The Ti-6Al-4V mixtures were found to behave synergistically, while the Co-Cr-Mo and 316L mixtures behaved antagonistically. By providing insight into degradation product toxicity and elemental interaction, these experiments demonstrate the utility of employing bioluminescent bacterial assays to investigate biocompatibility of implant materials. Further studies to more closely simulate in vivo conditions, though, are required to fully gauge their potential in this regard.

Algorithms↗

PubMed1991

Osteoblast responses to orthopedic implant materials in vitro.

Responses of neonatal rat calvarial osteoblasts to a variety of orthopedic implant materials were examined in vitro. Attachment, proliferation, and collagen synthesis of a well-characterized line of osteoblasts with 316L stainless steel, Ti-6Al-4V, Co-Cr-Mo, PMMA, hydroxyapatite, borosilicate glass, and tissue culture polystyrene were studied. Cell adhesion and growth were similar on nonapatitic materials. In contrast, attachment and growth of osteoblasts were significantly lower and slower, respectively, on hydroxyapatite. Collagen synthesis per cell and relative collagen synthesis, however, were comparable on all the materials tested.

Animals↗

PubMed2003

Involvement of angiopoietin-tie system in bovine follicular development and atresia: messenger RNA expression in theca interna and effect on steroid secretion.

Angiogenesis is involved in the local mechanisms that regulate follicular development and ovulation. Recently, the angiopoietin (ANPT)-Tie system has been shown to be required to regulate angiogenesis and blood vessel regression. Expression of the ANPT-Tie system in the cyclic ovary suggests that the relative changes in the expression of ANPT-1 and ANPT-2 influence the stability of ovarian blood vessels. In this study, we investigated 1) the mRNA expression for ANPT-1, ANPT-2, and endothelial cell-specific receptors Tie1 and Tie2 in the theca interna (TI) of the bovine developing, mature, and atretic follicles by using a semiquantitative reverse transcription polymerase chain reaction assay and 2) the effect of ANPT on the secretion of steroid hormones from bovine preovulatory follicles in vitro using a microdialysis system (MDS) implanted in the thecal layer. Bovine follicles were classified as developing, mature, and atretic according to size, follicular fluid content of estradiol (E2) and progesterone (P4), and characteristics of granulosa cells (GCs). Both ANPT and Tie mRNA were expressed in the TI, whereas GCs expressed ANPT mRNA only. The expression of ANPT-2 mRNA was decreased in the mature follicles. This decrease resulted in a decrease in the ANPT-2:ANPT-1 ratio (an index of instability of blood vessels), indicating that the blood vessels became more stable or mature. The early atretic follicles showed a higher ANPT-2:ANPT-1 ratio and higher Tie2 mRNA expression than did other follicles at healthy or later atretic stages. This finding may imply that blood vessels become unstable at the initial stage of follicular atresia. In both mid and late atretic follicles, Tie2 mRNA expression dramatically decreased, indicating a disruption of the ANPT-Tie system. In the MDS experiment, an infusion of ANPT-1 or ANPT-2 increased P4 release, whereas both ANPTs inhibited the release of androstenedione. ANPT-1 also increased E2 release. These results showed that the mRNA expression for ANPT-1, ANPT-2, Tie1, and Tie2 changes during follicular development, maturation, and atresia in bovine follicles and that ANPTs affect steroidogenesis in the preovulatory follicle. The results suggest that the ANPT-Tie system is involved the structural (angiogenesis) and secretory changes that occur during follicular development and atresia.

Angiopoietin-1↗

PubMed2005

Design, characterization and testing of Ti-based multicomponent coatings for load-bearing medical applications.

A comparative investigation of multicomponent thin films based on the systems Ti-Ca-C-O-(N), Ti-Zr-C-O-(N), Ti-Si-Zr-O-(N) and Ti-Nb-C-(N) is presented. TiC(0.5) + 10%CaO, TiC0.5 + 20%CaO, TiC0.5 + 10%ZrO2, TiC0.5 + 20%ZrO2, Ti5Si3 + 10%ZrO2, TiC0.5 + 10%Nb2C and TiC0.5 + 30%Nb2C composite targets were manufactured by means of self-propagating high-temperature synthesis, followed by DC magnetron sputtering in an atmosphere of argon or in a gaseous mixture of argon and nitrogen. The films were characterized in terms of their structure, chemical composition, surface topography, hardness, elastic modulus, elastic recovery, surface charge, friction coefficient, and wear rate. The biocompatibility of the films was evaluated by both in vitro and in vivo experiments. In vitro studies involved the investigation of the proliferation of Rat-1 fibroblasts and IAR-2 epithelial cells on the tested films, morphometric analysis and actin cytoskeleton staining of the cells cultivated on the films. In vivo studies were fulfilled by subcutaneous implantation of Teflon plates coated with the tested films in mice and analysis of the population of cells on the surfaces. The films deposited under optimal conditions showed high hardness in the range of 30-37 GPa, significant reduced Young's modulus, low friction coefficient down to 0.1-0.2 and low wear rate in comparison with conventional magnetron-sputtered TiC and TiN films. The surface of all films was negatively charged with an outstanding shift between the Ar and Ar + N2 Zeta potential curves that reaches 5 mV at the highest pH values. We did not detect statistically significant differences in the attachment, spreading and cell shape of cultured IAR-2 and Rat-1 cells on the Ti-Ca-C-O-(N), Ti-Zr-C-O-(N) (TiC0.5 + 10%ZrO2 target), Ti-Si-Zr-O-(N) films and the uncoated substrata. The adhesion and proliferation of cultured cells in vitro was perfect at all investigated films. Assessment of the population of cells covering on the Teflon plates coated with the Ti-Ca-C-O-(N) and Ti-Zr-C-O-(N) films after 16 weeks of subcutaneous implantation revealed the high biocompatibility level of tested films and absence of inflammatory reactions in mice. Contrary, the epitheliocytes and fibroblasts cultivated on the Ti-Zr-C-O-(N) (TiC0.5 + 20%ZrO2 target) and Ti-Nb-C-(N) films had disturbing actin cytoskeleton.

Actins↗

PubMed2005

New chemical treatment for bioactive titanium alloy with high corrosion resistance.

It was recently claimed that titanium metal and its alloys can bond to the living bone, without being coated by apatite (VPS coatings), but by being chemically and heat-treated. The bioactivity of treated titanium is of interest because of the opportunity to obtain orthopaedic or dental implants presenting, at the same time, high toughness, strength and fatigue resistance as well as bone-bonding ability. The bioactive behaviour of the treated implants is due to the presence of a modified surface, which, during soaking in body fluid, promotes the precipitation of apatite. The apatite formed is strongly bonded to the substrate and promotes living bone bonding. In this work were characterised samples of Ti-6Al-7Nb alloy with surfaces presenting a different chemical and mechanical state. The aim of the research was twofold. The first objective was to characterise chemically and heat-treated samples with different surface topography, in order to define the best conditions for osteogenic integration. The second aim was to assess the corrosion behaviour of the bioactive implants, because they expose a microporous and quite thin modified surface layer. No-treated and passivated samples, with a surface state closed to that nowadays used on implants, were used as reference. The surface structure, morphology, electrochemical behaviour and bioactivity of the different samples were assessed by means of XRD, SEM-EDS, anodic polarizations, open circuit measurements and in-vitro tests. Results evidence that it is possible to modify the surface of the Ti-6Al-7Nb alloy in order to obtain the formation of a bioactive layer and that the substrate roughness influences the characteristics of the surface layer formed. It was also evidenced that the as treated surfaces present inadequate corrosion behaviour, so a new two-step chemical treatment has been developed in order to obtain a bioactive material with good corrosion resistance.

Biocompatible Materials↗

PubMed2003

[Microcosmic analysis of amino group implanted titanium].

OBJECTIVE: The purpose of this study was to determine the effects of amino group implantation on the surface structures of titanium. METHODS: The amino groups were implanted into the surfaces of titanium using 100 keV amino group ions at ambient temperature (25 degrees C) with the following three different doses: 5 x 10(17), 1 x 10(17) and 5 x 10(16) ions per cm2. The current density of the ion-beam was (10 microA/cm2. The modified surfaces were characterized using X-ray photoelectron spectroscopy (XPS) to determine the chemical components of the modified surfaces. A scanning electron microscope (SEM) was used to study the physical structure of the surfaces. RESULTS: The wide XPS profiles, the binding energy data and the SEM photos were obtained. The XPS showed that the modified surface contained Ti, O, C and N. The possible chemical states were speculated using Gauss matching analysis. There was no significant difference between the surfaces with and without implanted amino groups. CONCLUSION: The XPS data reveals that the structure of the modified surface layer of aminogroup-implanted titanium is TiN, comprising a complex structure of titanium and amino compound near the surface. The SEM Photos show that this technique has little effect on the surface structures of materials.

Amines↗

PubMed2006

Biological responses in osteoblast-like cell line according to thin layer hydroxyapatite coatings on anodized titanium.

Several features of the implant surface, such as roughness, topography and composition play a relevant role in implant integration with bone. This study was conducted in order to determine the effects of various thin layer hydroxyapatite (HA) coatings on anodized Ti surfaces on the biological responses of a human osteoblast-like cell line (MG63). MG63 cells were cultured on 100 nm HA (100 nm HA coating on anodized surface), 500-700 nm HA (500-700 nm HA coating on anodized surface), 1 mum HA (1 mum HA coating on anodized surface) and anodize (non-HA coating on anodized surface) Ti. The morphology of these cells was assessed by scanning electron microscopy (SEM). The cDNAs prepared from the total RNAs of the MG63 were hybridized into a human cDNA microarray (1152 elements). The appearances of the surfaces observed by SEM were different on each of the four dental substrate types. MG63 cells cultured on 100 nm HA, 1 mum HA and anodize exhibited cell-matrix interactions. It was 500-700 nm HA surface showing cell-cell interaction. In the expression of genes involved in osseointegration, several genes, including bone morphogenetic protein 2, latent transforming growth factor beta binding protein 1, catenin (cadherin-associated protein), integrin, PDGFRB and GDF-1 growth differentiation factor 1 were up-regulated on the different surfaces. Several genes, including fibroblast growth factor receptor 3, fibroblast growth factor 12 and CD4 were down-regulated on the different surfaces. The attachment and expression of key osteogenic regulatory genes were enhanced by the surface morphology of the dental materials used.

Cell Survival↗