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PubMed1990

Bactericidal properties of a titanium-peroxy gel obtained from metallic titanium and hydrogen peroxide.

A stable titanium-peroxy-radical complex is formed when metallic titanium interacts with hydrogen peroxide. The radical appears as one component in an aqueous gel formed when excess peroxides have been (catalytically) decomposed. The interaction between titanium and hydrogen peroxide may be of importance also in vivo during an inflammatory response at the implant. We report in this paper on the bactericidal effects of the titanium gel in the lacto- and myeloperoxidase-halogen systems. Escherichia coli viable count was used to evaluate the bactericidal properties of the gel and of H2O2 for comparison. The gel had only small or no toxic properties at high dilutions. Higher concentrations of the gel had bactericidal properties similar to those of H2O2. The results indicate that at physiological pH, the decomposition products of the gel ae titanium hydroxide (Ti(IV)(OH-)4) and hydrogen peroxide (H2O2). It was found that the gel probably oxidizes glutathione directly in contrast to H2O2, which needs a peroxidase to do so. A model for the interaction between titanium and hydrogen peroxide is suggested. Its consequences for the properties of titanium in vivo are also discussed.

Chlorine↗
PubMed1995

Experimental long-term study of titanium ions eluted from pure titanium miniplates.

A long-term study of titanium miniplates, which are in wide clinical use, was conducted to clarify their usefulness as a permanent fixing device. We examined by scanning electron microscopy the surfaces of removed plates and the accumulation of titanium in the organs of Japanese white rabbits. Two years after implantation the titanium plates were only slightly corroded. In addition, marked titanium accumulation was noted in the organs, especially in the lungs. However, the accumulation of titanium in the organs of animals with left distomolar mandibular fracture was highest at 3 months after implantation, and then gradually decreased over 2 years. Titanium miniplates have recently been used clinically in humans and no adverse reactions have yet been reported. The present findings suggest the use of titanium miniplates as permanent fixing devices.

Animals↗
PubMed2000

Investigation of titanium leak to bone tissue surrounding dental titanium implant: electron microscopic findings and analysis by electron diffraction.

This study investigated the tissue response associated with dental titanium implants. The mandibular third and fourth premolars and first molar of three adult beagle dogs were extracted bilaterally. Healing was then allowed for 3 months. Six titanium implants were placed in the mandibles of a dog. Three weeks after the implantation, mandibular sections containing the implants were retrieved with the use of a bone saw and investigated by light and electron microscopy, X-ray microanalyzer, and electron diffraction. Scanning electron microscopic observation showed titanium particles on the implant-bone interface, and investigation by microanalyzer revealed titanium not only on the implant-bone interface but also in the bone tissue. Transmission electron microscopic observation and investigation by electron diffraction showed titanium in the bone matrix and cells other than macrophages. In this study, titanium particles from the dental implant were recognized morphologically in the surrounding bone tissue. Thus, study of the influence of titanium particles on the human body is needed.

Animals↗
PubMed2006

Destination of titanium particles detached from titanium plasma sprayed implants.

Small titanium particles may detach from titanium plasma sprayed (TPS) implants during implant insertion, when no preliminary tapping is used, probably for the frictional force between titanium coating and host bone. Aim of this study was to investigate the destination of these titanium particles observed in the peri-implant environment. Twenty-four TPS screws were implanted in tibiae of two sheep. Fourteen and 90 days after implantation the implants with the surrounding bone were removed and processed to be analyzed by light microscope and scanning electron microscope (secondary electron and back-scattered electron probes). Small titanium particles detached from the unloaded TPS implants were observed both in the newly-formed bone matrix and in marrow tissue. Histomorphometric analysis showed that both at 14 and 90 days after implantation the titanium particles appeared more concentrated in marrow tissue than in calcified bone matrix, decreasing by 66.4% over time. In particular, smaller particles (<250 microm(2)) decreased by 81.5%, whereas the larger ones (250-2000 microm(2)) did not show any significant variations over time, suggesting that most of the smaller particles may undergo to ionic dissolution, probably migrating into the peri-implant marrow lacunae. A slight migration of titanium particles from the implant surface towards the more distant peri-implant tissues was also demonstrated over time.

Animals↗
PubMed1997

Oxidation behavior of surface-modified titanium for titanium-ceramic restorations.

STATEMENT OF PROBLEM: Titanium-ceramic bonding is an unsolved problem for the current use of titanium-ceramic restorations. PURPOSE: The purpose of the study was to characterize oxide formation on titanium surfaces at porcelain sintering temperatures and to determine the effect of chromium coating methods on titanium oxide formation. MATERIAL AND METHODS: Sputter coating and electroplating methods of chromium application were compared and combined. RESULTS: Porous, weak titanium oxide formation on uncoated samples was demonstrated at porcelain sintering temperatures. Groups with chromium coating as an oxygen diffusion barrier exhibited lower oxidation rates, except samples coated by sputtering alone. Temperature effect was found to have the greatest significance on titanium oxidation rate. The overall lowest oxidation rate was located in the group that had chromium coating by the combined coating method and was oxidized at 750 degrees C. CONCLUSION: The electroplating method requires further investigation and development so that a uniform chromium layer can be deposited on titanium.

Analysis of Variance↗
PubMed1997

Clinical evaluation of hydroxyapatite-coated titanium plasma-sprayed and titanium plasma-sprayed cylinder dental implants: a preliminary report.

OBJECTIVE: The purpose of this article was to present the preliminary results of a prospective clinical trial comparing titanium plasma-sprayed versus hydroxyapatite-coated titanium plasma-sprayed cylinder (press fit) implants in different regions of the mouth. STUDY DESIGN: Sixty-five subjects met the inclusion requirements. Surgery was done in two phases by four experienced surgeons. Implant placement and abutment connection were separated by 3 to 4 months in the mandible, 6 to 7 months in the maxilla. Patients were assigned to either titanium plasma-sprayed or hydroxyapatite-coated implants on the day of surgery. Implant placement was not stratified for the region of the jaws. Outcome assessment was failure (loss) of an implant before or within 3 months of second phase surgery. RESULTS: Three hundred fifty-two implants equally distributed between titanium plasma-sprayed and hydroxyapatite-coated titanium plasma-sprayed implants were placed in four different sites; anterior maxilla, posterior maxilla, anterior mandible, and posterior mandible. There were a total of 15 failures (4.26%). Overall, titanium plasma-sprayed implants showed a higher but not significant failure rate compared with hydroxyapatite-coated implants (p = 0.06). Although not statistically significant, we believe that a smoking history played an important role in the failure of implants. CONCLUSION: This study suggests that an hydroxyapatite-coating of an implant allows superior initial integration when compared with a titanium plasma-sprayed surface.

Adult↗
PubMed2002

Removal of titanium plates coated with anodic titanium oxide ceramic: retrospective study.

Transformation of the surface of metallic titanium with titanium oxides prepared in various ways is a modern procedure. For more than 15 years, the authors have been utilizing fixing elements coated with titanium oxide ceramics, prepared by anodic oxidation and thermal treatment, for purposes of jawbone osteosynthesis. The aim of the authors' work was to assess the extent to which the titanium oxide ceramic coating influences the fate of the plates used for osteosynthesis within the human organism, in regard to the possible need for their removal. During a 5-year period, 108 of 1,396 plates coated with anodic titanium oxide had to be removed for various reasons: plate exposure (47), osteomyelitis (25), palpable swelling and tenderness (21), patient request for psychological reasons (13), or fracture of the plate (2). In none of these 108 cases was metallosis observed, which otherwise is reported relatively frequently in the vicinity of traditional titanium fixing elements, nor was any tissue damage connected with the surface of the plates. The results indicate the favorable properties of the titanium oxide ceramic surface.

Adolescent↗
PubMed2002

[Follow-up examinations after removal of titanium plates coated with anodic titanium oxide ceramic].

Transformation of the titanium metal surface with titanium oxides produced in various ways belongs among the most up-to-date procedures. The authors as pioneers in this field (e.g. Nobel Biocare TiUnite surface), have been utilizing for more than 15 years dental root implants and fixing elements (for mandibular osteosynthesis) coated with titanium oxide ceramics, produced by anodic oxidation and thermal treatment. The aim of this work was to assess the extent to which a titanium oxide ceramic coating influences the fate of plates applied for osteosynthesis within the human body. During a 5-year period (1995-1999), 108 of 1396 titanium oxide ceramic plates had to be removed for various reasons: loosening of the plate [47], osteomyelitis [25], a palpable swelling and tenderness [21] at the request of the patient for psychological reasons (13) or breaking of the plate [2]. When these 108 plates were removed, it was not possible to detect metallosis in even a single case; nor was there any tissue damage that could be attributed to the surface of the plates, whereas the literature data indicate that such damage is relatively frequent in the environment of traditional titanium fixing elements. The present investigation confirms the favourable properties of the titanium oxide ceramic surface.

Adolescent↗
PubMed1990

[Studies on titanium casting. (1) Influence of the mold temperature on titanium castings].

Pure titanium and titanium alloys have excellent biocompatibility, excellent corrosion tarnish resistance, a quarter of the specific gravity of gold base alloys and suitable mechanical properties for dental clinical use. However, titanium has some undesirable characteristics. For example, it has a high melting temperature and chemical reactivity at high temperatures. The investigate influence of the mold temperature on castability and mechanical properties of the titanium castings was study. The castability was found to be good at various mold temperatures, but the higher the mold temperature during casting, the greater the adhesive phenomenon between titanium surface and the investment. From the EPMA observation of the surface layer on the titanium castings, an Si- rich layer whose thickness increased considerably with increasing temperature was observed. The Vickers hardness in the surface layer was greater than that in the inner part. At a higher mold temperature during casting the thickness of the high Vickers hardness layer was increased. There was a relationship between the Vickers hardness value and the thickness of Si rich layer. In the tensile strength test of titanium castings, elongation values decrease and tensile strength values increased with the rise in mold temperature.

Dental Alloys↗
PubMed1993

Titanium-porcelain system. Part I: Oxidation kinetics of nitrided pure titanium, simulated to porcelain firing process.

The bonding strength of porcelains to metals depends on the oxide layer between the porcelain and the metal. Oxidation of a metal surface increases the bonding strength, whereas excessive oxidation decreases it. Titanium and its alloys are gaining acceptance for dental use since they exhibit excellent biocompatibility, corrosion resistance, low specific gravity, good mechanical properties, and low cost. However, titanium suffers from its violent reactivity with oxygen at high temperatures that yields an excessive thick layer of TiO2, and this presents difficulties with porcelain bonding. The present study deals with the oxidation kinetics of titanium simulated to porcelain firing and evaluating surface nitridation of titanium as a process of controlling the oxidation behavior of titanium. Nitrided samples with the Arc Ion Plating PVD process and un-nitrided control commercially pure titanium (CPT, Grade 1) were subjected to oxidation simulating firing of Procera porcelain with 550 degrees, 700 degrees, and 800 degrees C firing temperatures for 10 min in both 1 and 0.1 atmospheric air. Weight difference before and after oxidation was calculated and the parabolic rate constant, Kp (mg2/cm4/s), was plotted against inverse absolute temperature. Surface layers of the samples were subjected to x-ray and electron diffraction techniques for phase identifications. Results revealed that both nitrided and un-nitrided samples obey a parabolic rate law with activation energy of 50 kcal/mol. In addition this study shows that nitrided CPT had a Kp about 5 times lower than the un-nitrided CPT and hence the former needs about 2.24 times longer oxidation time to show the same degree of oxidation. Phase identification resulted in confirming the presence of TiO2 as the oxide film in both groups but with 1-2 microns thickness for the un-nitrided CPT and 0.3-0.5 micron thickness for the nitrided samples. Therefore it can be concluded that nitridation of titanium surface can be effective in controlling the surface oxide thickness that might ensure satisfactory bonding with porcelain.

Crystallography↗
PubMed1995

[Experimental research on porcelain fused to the surface of pure titanium and titanium alloys].

Titanium material has been widely used in prosthodontics since the end of 1980s. However, the research on porcelain fused to the surfaces of titanium material was quite few. This article introduced the technological process of low-fusing dental porcelain--Ceratin fused to pure titanium and titanium alloys. The values of the bond strength of Ceratin and titanium substrates were obtained by shearing test with INSTRON Model-1185. The average value of the shearing strength between TA2 and Ceratin was 31. 01MPa. The corresponding value between TC4 and Ceratin was 33.73MPa. The interface between Ceratin and titanium substrate was observed with scanning electron microscope (SEM). The results of this research proposed that it is hopeful that Ceratin is used as special procelain with titanium material.

Dental Porcelain↗
PubMedDate not supplied

A quantitative comparison of machined commercially pure titanium and titanium-aluminum-vanadium implants in rabbit bone.

Screw-shaped implants made from rods of commercially pure titanium (grade 1) and titanium-aluminum-vanadium (grade 5) were machined, and the implant surface structures were numerically described before being placed in rabbit tibiae for healing periods of 1 months, 6 months, and 12 months. Quantitative comparisons of the removal torque (Ncm) necessary to loosen the implants from the bone bed were performed. Short-term (1 month) observations revealed no significant differences between the two tested materials. However, after 6 and 12 months, the commercially pure titanium implants were significantly more stable in the bone bed, as compared to the alloy samples. After 6 months, the commercially pure titanium had a mean removal torque of 29 Ncm versus 23 for the alloy (P = .01), and after 12 months, the mean removal torque was 38 Ncm for commercially pure titanium as compared to 35 Ncm for the alloy (P = .01). Quantifications of the bone tissue response to the materials did not show any significant differences; however, the commercially pure titanium showed a tendency to have a higher percentage of bone in contact with the implant as compared to the alloy screws. Bone volumes in the threads were similar. The absence of any quantitative light microscopic difference after 1 month following placement may relate to the fact that there was a sparse amount of bone, since the tissue was in the organization/granulation phase. After 6 and 12 months of follow-up, substantial bone formation had occurred, resulting in significantly increased removal torques for the commercially pure titanium samples.

Alloys↗
PubMed1998

Adducts of Titanium Tetrachloride with Alkylselenium Compounds: Molecular Precursors to Titanium Diselenide Films.

Treatment of titanium tetrachloride (2 equiv) with dimethyl diselenide or diethyl diselenide (1 equiv) in hexane at 0 degrees C, followed by crystallization at -20 degrees C, afforded (TiCl(4))(2)(Se(2)(CH(3))(2)) (78%) and (TiCl(4))(2)(Se(2)(CH(2)CH(3))(2)) (63%), respectively, as red and orange crystalline solids. (TiCl(4))(2)(Se(2)(CH(2)CH(3))(2)) is stable in solution and in the solid state at 23 degrees C, but (TiCl(4))(2)(Se(2)(CH(3))(2)) decomposes to TiCl(4)(Se(CH(3))(2))(2), gray selenium, and other products upon standing in hexane solution, in the solid state, or upon sublimation at 250 degrees C. Treatment of titanium tetrachloride with 2 equiv of dimethyl selenide or diethyl selenide in hexane at ambient temperature afforded a spectroscopically pure brick red solid of TiCl(4)(Se(CH(3))(2))(2) (96%) or TiCl(4)(Se(CH(2)CH(3))(2))(2) (96%), respectively. X-ray crystal structures of (TiCl(4))(2)(Se(2)(CH(2)CH(3))(2)), TiCl(4)(Se(CH(3))(2))(2), and TiCl(4)(Se(CH(2)CH(3))(2))(2) were determined to establish solid state nuclearities. (TiCl(4))(2)(Se(2)(CH(2)CH(3))(2)) crystallizes in the hexagonal space group P3(1)21 with a = 12.106(1) Å, c = 10.786(1) Å, V = 1368.8(4) Å(3), and Z = 3. TiCl(4)(Se(CH(3))(2))(2) crystallizes in the monoclinic space group P2(1)/n with a = 8.175(1) Å, b = 13.051(1) Å, c = 16.871(3) Å, beta = 102.675(8) degrees, V = 1756.3(2) Å(3), and Z = 4. TiCl(4)(Se(CH(2)CH(3))(2))(2) crystallizes in the monoclinic space group P2(1)/n with a = 6.404(4) Å, b = 16.376(7) Å, c = 13.058(8) Å, beta = 101.45(4) degrees, V = 1342(1) Å(3), and Z = 4. TiCl(4)(Se(CH(3))(2))(2) and TiCl(4)(Se(CH(2)CH(3))(2))(2) were evaluated as precursors to titanium diselenide films. TiCl(4)(Se(CH(3))(2))(2) was not a good precursor, but TiCl(4)(Se(CH(2)CH(3))(2))(2) afforded rose-bronze colored titanium diselenide films at substrate temperatures of 500-600 degrees C. The films were characterized by X-ray powder diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Surprisingly, titanium diselenide films prepared from TiCl(4)(Se(CH(2)CH(3))(2))(2) are moisture sensitive and are apparently hydrolyzed by ambient moisture to titanium dioxide and hydrogen selenide. The relevance of the coordination chemistry to the development of precursors to titanium diselenide films is discussed.

Journal Article↗
PubMed1997

Systemic titanium levels in rabbits with a titanium implant in the absence of wear.

All non-noble metals and alloys will release metallic species into the body. This raises the issue of amount and fate, i.e. transport and storage, of these metal dissolution products. For titanium, the nature and extent of these systemic effects remain mostly unknown. In this study we investigated titanium levels in alleged target tissues in rabbits, both with and without a titanium implant functioning in the absence of wear, and compare these results to the limited body of literature concerning systemic levels of titanium. Titanium fibre felts were implanted into the tibia of rabbits. At various time points, lung, spleen, and muscle samples were collected from these rabbits as well as two groups of control rabbits. The samples were analysed for titanium concentration using electrothermal atomic absorption spectrophotometry. The data for the implant groups show that titanium levels in these tissues do not increase in comparison with controls up to 1 y after implantation.

Journal Article↗
PubMed2006

Hydrogen absorption of titanium and nickel-titanium alloys during long-term immersion in neutral fluoride solution.

Hydrogen absorption of biomedical titanium and Ni-Ti alloys in a neutral fluoride (2.0% NaF) solution for up to 10,000 h at 37 degrees C has been evaluated by means of hydrogen thermal desorption analysis. For alpha titanium (commercial pure titanium), the amount of absorbed hydrogen was, at most, 10-30 mass ppm, and the corrosion product and hydride formation were revealed on the surface of the specimen by X-ray diffraction analysis. Ni-Ti superelastic alloy absorbed approximately 150 mass ppm of hydrogen, which was probably sufficient to result in the pronounced degradation of the mechanical properties, although corrosion was hardly observed. In contrast, hydrogen absorption of alpha-beta titanium (Ti-6Al-4V) and beta titanium (Ti-11.3Mo-6.6Zr-4.3Sn) alloys was negligible, although general corrosion was observed. The results of the present study indicate that the susceptibility of titanium and Ni-Ti alloys to hydrogen absorption in the neutral fluoride solution is different from that in the acidic fluoride solution reported previously.

Biocompatible Materials↗
PubMed1996

Titanium and bioactive glass-ceramic coated titanium as materials for keratoprosthesis.

The current problem with keratoprosthesis is the ingrowth of corneal or conjunctival epithelium into the anterior chamber. This may lead to infections and extrusion of the prosthesis as well as to the development of retroprosthetic membrane and secondary glaucoma. Glass-ceramic coated and uncoated titanium has been tested as material for the keratoprosthesis to prevent epithelial ingrowth. Twenty-two Supra-Descemet's membrane keratoprostheses were inserted in the eyes of 22 rabbits for 1, 2, 4, 8, or 12 months. The prosthesis had an optic part made of polymethylmetacrylate (PMMA). The support for the optic part and the flange of the prosthesis were made of titanium. Eleven of the prostheses were coated with glass-ceramic. The histological sections of the enucleated eyes were prepared through the central part of the cornea and the prosthesis using a cutting-grinding method. The histological analysis was made on both halves of the implants separately giving two analysis areas in each eye. All 11 titanium prostheses were retained for the time period planned. Two glass-ceramic coated prostheses were lost at 2 and 4 weeks, respectively. This was caused by difficulties at surgery due to a thick coating. These eyes were excluded from the histological analysis. No significant ingrowth of epithelium was seen in 15/18 (83%) and in 16/22 (73%) of the analysed areas of the glass-ceramic coated and titanium prostheses, respectively. Titanium appears to be a suitable material for the keratoprosthesis. The ingrowth of the epithelium may be hindered further by coating the titanium with bioactive glass-ceramic.

Animals↗
PubMed1981

Comparison of nickel-titanium and beta titanium wire sizes to conventional orthodontic arch wire materials.

The theoretical strength, stiffness, and range of nickel-titanium and beta titanium arch wires are compared with several stainless steel or cobalt-chrome wires. With the apparent stiffness as the criterion, equivalent force systems are established in the elastic region between the conventional and the new arch wire alloys. In bending, such calculations show that the nickel-titanium alloy makes superior starting wire, 0.016, 0.018, and 0.018 by 0.018 inch wires having stiffnesses similar to multistranded 0.0175, round 0.012, and 0.014 inch stainless steel wires, respectively, but with about twice the strength and range. By the same method of analysis, the beta titanium alloy makes a particularly good intermediate arch wire, the 0.017 by 0.025 and the 0.019 by 0.025 inch sizes having about twice the stiffness in the horizontal plane but equal rigidity in the vertical plane when compared with 0.016 and 0.018 inch stainless steel. In torsion not even the largest sizes of nickel-titanium (0.021 by 0.025 inch) or beta titanium (0.019 by 0.025 inch) wire meet the stiffness requirements of an 0.019 by 0.026 inch stainless steel wire, thereby making the established alloys the finishing wire of choice.

Alloys↗
PubMed1999

Formation of titanium(IV) transferrin by reaction of human serum apotransferrin with titanium complexes.

The reaction of human serum apotransferrin with titanium(IV) citrate under physiological conditions results in the formation of a specific bis-titanium(IV) transferrin adduct (Ti2Tf hereafter) with two titanium(IV) ions loaded at the iron binding sites. The same specific Ti2Tf complex is formed by reacting apotransferrin with titanium(III) chloride and exposing the sample to air. The derivative thus obtained was characterized by spectroscopic techniques, including absorption, UV difference, circular dichroism and 13C NMR spectroscopies, and shown to be stable within the pH range 5.5-9.0. Surprisingly, the reaction of apoTf with titanium(IV) nitrilotriacetate (NTA) does not lead to formation of appreciable amounts of Ti2Tf, even after long incubation times, although some weak interactions of Ti(IV)-NTA with apoTf are spectroscopically detected. Implications of the present results for a role of transferrin in the uptake, transport and delivery of soluble titanium(IV) compounds under physiological conditions are discussed.

Apoproteins↗