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At least 883 records · Page 49Linked to original sources
PubMed1984

Metal ion release from titanium-based prosthetic segmental replacements of long bones in baboons: a long-term study.

Forty-five baboons that had received titanium-based fiber metal composite segmental bone replacements were studied along with 13 controls without implants. Thirty-eight baboons with implants were sacrificed, and titanium, aluminum, and vanadium levels were assayed in homogenized lung, kidney, spleen, liver, adjacent muscle, and regional lymph nodes. In seven living baboons with implants, blood and urine samples were obtained for trace metal analysis as well as for biochemical and hematological profiles. In the 38 sacrificed baboons with implants, increased titanium levels were noted in the lungs, spleen, adjacent muscle (quadriceps, soleus, and triceps), and regional lymph nodes (inguinal, axillary, and popliteal) in comparison to those of six sacrificed controls without implants. In addition, vanadium was significantly elevated in the lungs of some animals, while aluminum increases were noted in adjacent muscle (quadriceps, soleus, and triceps), lung, and regional lymph nodes (inguinal, axillary, and popliteal). In the seven living baboons with implants, a sixfold increase (p less than 0.0005) in the urine titanium level was noted in comparison to that of seven living controls without implants. Additionally, elevated aluminum levels were found in the serum (p less than 0.0005) of the group with implants. Biochemical and hematological studies did not indicate statistically significant differences in serum electrolytes, in liver and renal function tests, or in complete blood counts between the seven living baboons with implants and their controls.

Aluminum↗
PubMed1999

Measurement and removal of adherent endotoxin from titanium particles and implant surfaces.

Aseptic loosening is thought to be due primarily to osteolysis induced by cytokines and prostaglandins that are produced in response to implant-derived wear particles. Because endotoxin has many of the same effects as have been reported for wear particles, we hypothesized that adherent endotoxin may be responsible for the biological responses induced by wear particles. We demonstrated the presence of significant levels of adherent endotoxin on commonly used preparations of titanium particles as well as on titanium and titanium-alloy implant surfaces. In contrast, supernatants obtained by centrifugation of particle suspensions contained approximately 1% as much endotoxin as did the particles. Therefore, it is erroneous to assume that particles do not contain endotoxin on the basis of data that it cannot be detected in their supernatants or filtrates. These results emphasize the importance of considering the potential role of adherent endotoxin when examining the in vitro effects of wear particles and the in vivo performance of orthopaedic implants. We also developed a protocol that removed more than 99.94% of the adherent endotoxin from the titanium particles without detectably affecting their size or shape. The removal of adherent endotoxin will allow comparison of the biological responses induced by particles with or without adherent endotoxin.

Endotoxins↗
PubMed2005

Novel method for studying photolability of topical formulations: a case study of titanium dioxide stabilization of ketoprofen.

Sunlight may decompose active substances and excipients in pharmaceuticals. This may cause formulation problems as well as induce adverse skin reactions. The photodecomposition of topical preparations may occur on the skin surface, but also deeper in the skin after penetration of light into the viable tissues. The aim of the present study was to investigate whether microparticles of titanium dioxide could protect against photodecomposition using ketoprofen as a photolabile model substance. The results showed quality differences between titanium dioxide, where surface-coated particles were superior to pharmaceutical grades in reducing the degradation in vitro. The protective effect was also studied in humans. The skin was treated for 3 h with the gels and then exposed to ultraviolet (UV) light (11.7 J/cm2 UVA and 5.4 mJ/cm2 UVB). Layers of the stratum corneum were then removed by consecutive tape strippings and assayed for content of ketoprofen. The remaining amount was higher in the different stratum corneum compartments after treatment with a gel containing 4% coated titanium dioxide compared with a transparent gel. Thus, surface-coated microparticles of titanium dioxide may well be of clinical benefit in protecting photolabile drug substances against sunlight.

Administration, Topical↗
PubMed2004

Design of new titanium alloys for orthopaedic applications.

Parallel to the biofunctionalisation of existing materials, innovation in biomaterials engineering has led to the specific design of titanium alloys for medical applications. Studies of the biological behaviour of metallic elements have shown that the composition and structure of the material should be carefully tailored to minimise adverse body reactions and to enhance implant longevity, respectively. Consequently, interest has focused on a new family of titanium alloys: Ti-6Mo-3Fe-5Ta, Ti-4Mo-2Fe-5Ta and Ti-6Mo-3Fe-5Zr-5Hf alloys. The non-toxicity of the specially designed titanium alloys compared with osteoblastic cells has been ascertained using MTT and RN tests. In addition, phase transformations upon thermal processing have been investigated, with comparison with a well-defined beta titanium alloy. Optimum thermal processing windows (above 550 degrees C) have been designed to generate a stable and nanostructured alpha phase from the isothermal omega phase that precipitates in a low temperature range (150-350 degrees C). The generation of such nanostructured microstructures should provide a promising opportunity to investigate tissue-biomaterial interactions at the scale of biomolecules such as proteins.

Alloys↗
PubMed2003

Initial stages of microbiologically influenced tarnishing on titanium after 20 months of immersion in freshwater.

This paper studies the initial stages of iridescent tarnishes on titanium heat exchanger tubes in contact with running freshwater on the river Tagus in Spain for up to 20 months. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy [(SEM with energy dispersive X-ray (EDX)] and X-ray photoelectron spectroscopy (XPS) in conjunction with argon-ion sputtering were the techniques used. The EIS data indicated a capacitive behavior, showing a semicircle that was better defined as the experimental time increased, indicating a decreasing tarnishing resistance of titanium. XPS and EDX results indicated that the main elements identified were calcium, phosphorus, nitrogen, and iron. The amount of these elements was higher on the tarnished titanium specimens than on the untarnished specimens. SEM analysis showed the presence of diatoms in the iridescent tarnishes on titanium tubes.

Animals↗
PubMed2001

Nine-year results of Müller cemented titanium Straight Stems in total hip replacement.

At the Orthopaedic Department of the University of Basel, a total of 540 cemented Müller titanium alloy (Ti6Al7Nb) Straight Stems were inserted between 1989 and 1993. A cohort of 120 consecutive patients (66 women, 54 men) with 126 prostheses operated on between March and December 1989 were followed clinically and radiologically in a prospective manner for a mean observation time of 9.1 years. In all cases, the Müller titanium alloy Straight Stem was combined with the senior author's (E.W.M.) Press-Fit Cup. The mean age of the patients at surgery was 66 (range 43-93) years. Fourty patients (41 hips) died, 9 were interviewed by telephone, none was 'lost to follow-up'. Seventy-one patients with 76 hip replacements were available for the follow-up. Four hips had been revised: two of them due to aseptic loosening of the femoral component, one because of a late infection--all after 9 years--and one owing to a periprosthetic fracture after 6 years. The 9-year overall survivorship is 96.8%, and for aseptic loosening of the stem 98.4%. None of the cups had to be revised for aseptic loosening. The clinical result (according to Merle d'Aubigné) was excellent and good in 88%, moderate in 8%, and poor in 4%. The radiological analysis showed no osteolysis or radiolucent lines in 59 prostheses (78%). Nine stems (12%) showed a radiolucent line. Focal osteolysis was detected in 8 cases (10%) in one or more Gruen zones. The distribution of the osteolyses shows that predominantly zones VII, VI, V, and II are affected in decreasing frequency. No osteolysis was detected on the acetabular side. Our results do not confirm the high rate of osteolysis and revisions with the Müller titanium alloy Straight Stem presented by some other institutions. The verdict on a specific endoprosthetic implant must be made by combined assessment of the design, the implant surface condition, the material, the cement, the cementing procedure and the operative technique. The statement made in earlier publications that cemented titanium alloy should not be used as a femoral stem prosthesis should be reconsidered.

Adult↗
PubMed2002

Management of tracheal stenosis with a titanium ring and nasal septal cartilage.

Surgical management of subglottic laryngeal and upper tracheal stenosis remains a formidable challenge. The significant number of proposed techniques only highlights the difficulties associated with effectively managing this problem. Between 1996 and 1999, seven patients with stenosis of the upper trachea were treated. The stenosis resulted from long-term intubation during intensive-care hospitalization in five patients and from tracheotomy complications in the other two. Six patients were male and one female, their ages ranging between 13 and 60 years. The mean postoperative observation period was 3 years (1.5-4.5 years). In all patients, the stenosis exclusively involved the upper tracheal segment, measuring from 2 to 5 cm in length. The stenotic area of the trachea is exposed, and the local application of a solution of mitomicin C for a duration of 4 min is performed. A graft consisting of cartilage and mucosa is harvested from the nasal septum and is fixed with sutures to a titanium semi-ring. After the fixation of the graft on the ring, the entire construct is placed on the stenosed segment of the exposed trachea. The graft must cover the anterior exposed face of the trachea with the lateral members of the semicircular titanium ring adjacent to the lateral walls of the trachea, externally. The lateral tracheal walls are attracted laterally with sutures and are attached on the edges of the semicircular titanium ring. Four of the patients in whom no tracheotomy had been performed preoperatively needed none at all intraoperatively, and they were decannulated normally at the end of the procedure. Tracheotomy was deemed necessary for one patient's safety and was maintained for 7 days. In one patient with a preoperative tracheotomy, the point of the tracheotomy was displaced lower on the trachea and was maintained there for 7 days. The course of management described here and employed on seven patients involves a safe surgical procedure with excellent results. The placement of the titanium ring offers very good support for the graft and maintains the patency of the tracheal lumen. The main reasons for the failure of techniques using only cartilage grafts are therefore avoided. The number of cases presented here is certainly too small to establish definite conclusions; however, the initial results are extremely satisfying and urge us to suggest the use of this method in indicated cases.

Adolescent↗
PubMed2006

Short-term results using Kurz titanium ossicular implants.

The efficiency of titanium middle ear prosthesis for ossicular reconstruction in chronic ear disease is investigated in a Scandinavian two-center retrospective study from a Norwegian tertiary otology referral center and a Finnish otology referral center. Retrospective chart reviews were performed for procedures involving 73 titanium prostheses between 1999 and 2004. All patients that underwent surgery including the Kurz Vario titanium prosthesis were included in the study, 38 procedures including the partial ossicular replacement prosthesis (PORP) and 35 procedures including the total ossicular replacement prosthesis (TORP). Mean follow-up was 14 months. The ossiculoplasty was performed alone (29 patients) or in combination with other chronic ear surgery procedures (34 patients). Comparisons of preoperative and postoperative pure tone averages (0.5, 1, 2, and 3 kHz) according to AAO-HNS guidelines are presented, as well as data for different PTA definitions. Otosurgery procedures, complications, revisions, and extrusion rates are reported. A postoperative air-bone gap (ABG) of <or=20 dB was obtained in 77% of the patients, 89% for the Bell (Porp) prosthesis, and 63% for the Arial (Torp) prosthesis. Overall mean pure tone averages improved 20.6 dB with ABG improvement of 19.3 dB. The overall extrusion rate was 5% (4 patients). Titanium prostheses have been easy and fast to handle and effective implants for reconstruction of the ossicular chain. We found no difference between reconstruction with or without cholesteatoma surgery during the same procedure. The combination of CWD and Torp gave significant inferior hearing thresholds as compared to Torp/CWU and Porp/CWD combinations.

Audiometry↗
PubMed2004

Effect of enamel matrix protein derivative on the attachment, proliferation, and viability of human SaOs(2) osteoblasts on titanium implants.

The purpose of the present study was to investigate the effects of an enamel matrix protein derivative (EMD) on attachment, proliferation, and viability of human SaOs(2) osteoblasts on titanium implants. A total of 220 sand-blasted and acid-etched (SLA) titanium discs were placed into 24-well culture plates. Before cell inoculation, McCoy's 5A medium (MCM) containing EMD at 25 micro g/ml, 50 micro g/ml, 100 micro g/ml, and 200 micro g/ml was added, and the culture plates were incubated for 30 min. As control, MCM alone was used. Human osteoblast-like cells (SaOs(2)) (2 x 10(4) cells, fourth passage) were suspended in MCM containing 1% penicillin/streptomycin and 10% fetal bovine serum and then inoculated into the well chambers. The medium was changed after 3 days without the addition of EMD. At days 1, 3, and 6, DNA content of the cells was assessed using the CyQuant cell proliferation assay kit, and mitochondrial activity of the cells was measured using a CellTiter-Glo luminescent cell viability assay. The presence of EMD on the titanium discs at days 1 and 6 was evaluated using immunofluorescence stain (IFS) by means of polyclonal antibodies against amelogenin. Additionally, cell morphology was investigated using scanning electron microscopy. Enamel matrix derivative at 25 micro g/ml, 50 micro g/ml, 100 micro g/ml, and 200 micro g/ml demonstrated similar increases in cell proliferation as the control medium at days 3 and 6 ( P>0.05 between groups, respectively). Proliferation, however, appeared to be ameliorated with increasing EMD concentrations. At 25 micro g/ml and 50 micro g/ml, EMD also demonstrated an increase in cell viability similar to the control medium at days 3 and 6 ( P>0.05 between groups, respectively), while EMD at 100 micro g/ml and 200 micro g/ml resulted in statistically significant higher increase in cell viability than in the control medium at day 6 ( P<0.001 between groups, respectively). In all test groups, IFS at day 6 was markedly lower than at day 1. Scanning electron microscopy revealed comparable cell morphology in all groups. Within the limits of the present study, it was concluded that EMD enhanced cell proliferation and viability of human SaOs(2) osteoblasts on SLA titanium implants in a concentration-dependent manner.

Animals↗
PubMed2003

A prospective clinical comparison of rectangular titanium cages and iliac crest autografts in anterior cervical discectomy and fusion.

The complications of autogenous bone grafting cause spinal surgeons to seek alternative methods for cervical spinal fusion. This prospective study was conducted to evaluate the safety and efficacy of rectangular titanium cages as compared to the widely performed iliac crest autograft fusion. Thirty-six patients with cervical disc disease in whom an anterior cervical approach was indicated for discectomy were included in a prospective controlled study protocol with 1-year follow-up. The first 18 consecutive patients received iliac crest autograft, while the next 18 received rectangular titanium cages. According to Odom's criteria, 15 of 18 (83%) patients in both groups experienced good to excellent functional recovery. According to the patient satisfaction index, 17 of 18 (94%) in both groups were satisfied. There were no significant differences in neck or arm pain. Fusion was present after 1 year in 16 of 18 (89%) patients in the iliac crest autograft group and 15 of 18 (83%) in the rectangular titanium cage group. In the autograft group, one case of pseudarthrosis was present, and marked hip pain was observed in four patients. There were no implant-related complications in the cage group. The authors conclude that titanium cages in anterior cervical discectomy constitute a safe and efficient alternative to iliac crest bone autograft.

Adult↗
PubMed2006

Improved mechanical properties of acrylic bone cement with short titanium fiber reinforcement.

Acrylic bone cements are widely used in total joint arthroplasties to grout the prosthesis to bone. The changes in the tensile properties and fracture toughness of polymethylmethacrylate (PMMA) bone cements obtained by the addition of control and heat treated short titanium fibers are studied. Heat treatment of titanium fibers is conducted to precipitate titania particles on the fiber surface to improve the biocompatibility of the metal. Control and heat treated short titanium fibers (250 micro long and 20 micro diameter) were used as reinforcements at 3 volume %. X-ray diffraction indicated the presence of a rutile form of titania due to the heat treatments. The tensile and fracture properties were improved by the addition of fibers. Bone cements reinforced with titanium fibers heated at 550 degrees C for 1 h followed by 800 degrees C for 30 minutes show the largest increase in fracture toughness along with the smallest changes in elastic modulus and needs to be further investigated.

Benzoyl Peroxide↗
PubMed2006

Bone response to a titanium aluminium nitride coating on metallic implants.

The design, surface characteristics and strength of metallic implants are dependant on their intended use and clinical application. Surface modifications of materials may enable reduction of the time taken for osseointegration and improve the biological response of bio-mechanically favourable metals and alloys. The influence of a titanium aluminium nitride (TAN) coating on the response of bone to commercially pure titanium and austenitic 18/8 stainless steel wire is reported. TAN coated and plain rods of stainless steel and commercially pure titanium were implanted into the mid-shaft of the femur of Wistar rats. The femurs were harvested at four weeks and processed for scanning electron and light microscopy. All implants exhibited a favourable response in bone with no evidence of fibrous encapsulation. There was no significant difference in the amount of new bone formed around the different rods (osseoconduction), however, there was a greater degree of shrinkage separation of bone from the coated rods than from the plain rods (p = 0.017 stainless steel and p = 0.0085 titanium). TAN coating may result in reduced osseointegration between bone and implant.

Aluminum Compounds↗
PubMed1984

Estimation of hydrogen peroxide in plant extracts using titanium(IV).

Methods for the estimation of hydrogen peroxide in acetone extracts using titanium(IV) are likely to overestimate hydrogen peroxide when applied to plant leaves. Pigments appear to co-precipitate with the titanium complex and cannot be removed by washing with solvents. Fluoride, which specifically removes the color of the titanium-peroxide complex, removes only some of the color from the reactions with plant extracts. This problem has been avoided by extracting tissues with trichloroacetic acid, and measuring peroxide against catalase-treated blanks by its reaction with the complex of titanium(IV) with 4-(2-pyridylazo) resorcinol. Levels of hydrogen peroxide in leaves of a variety of species were found to range from about 0.1 to 0.6 mumol X g-1.

Catalase↗
PubMed1994

Implants of pure titanium for internal fixation of the peripheral skeleton.

In a multicentre study, a clinical evaluation of the new titanium implants of the sizes 2.7, 2.0 and 1.5 mm was done. In seven centres, 133 patients were operated on and the personal, subjective opinions of the surgeons were recorded. In the opinion of these surgeons experienced in using steel implants, the outcome of the internal fixations was the same for titanium as for steel implants. Three metal-related complications occurred in the smallest size screw type (1.5 mm), namely, one screw broke and two bent. In the cases in which the implant had been removed, good tissue contact with the implant could be seen. Only in one case was there discolouring of the soft tissue due to titanium. It is recommended that surgeons who are used to handling stainless steel screws should be aware of the slightly different behaviour of titanium screws.

Adolescent↗
PubMed1991

Dimensional changes in casting titanium removable partial denture frameworks.

The difficulties encountered in casting titanium and its alloys have until recently hindered any widespread use of titanium in restorative dentistry. Now both equipment and materials are available for the routine use of titanium in the dental laboratory. This study used one of the casting systems and examined dimensional changes that occur during the construction of a removable partial denture framework. Nineteen castings were measured for horizontal and vertical plane changes. Results show these castings to have cross arch contraction, vertical plane expansion, and near neutral anterio-posterior change. It seems that pure titanium is within the range of dimension changes generally accepted for base metal removable partial denture alloys of the nickel-chromium variety.

Dental Casting Investment↗
PubMed1992

Radiographic appearance of titanium alloy prefabricated posts cemented with different luting materials.

Eight luting materials were compared to determine which of them obscured the radiographic image of a cemented titanium alloy prefabricated post. Eight extracted, endodontically treated, maxillary molar teeth were selected for the study. A post channel was prepared in the lingual root canal of each tooth and a titanium alloy prefabricated post was cemented with one of the selected luting materials. Preoperative, precementation, and postcementation radiographs were compared visually to determine the outline of the cemented titanium alloy post. Glass ionomer cements obscured the outline more than composite resin cements but less than zinc phosphate or polycarboxylate cements. Further study is indicated before recommendation of a luting material with titanium alloy prefabricated posts.

Alloys↗
PubMed1992

In vivo corrosion behavior of gold-plated versus titanium dental retention pins.

Two types of titanium dental retention pins and a gold-plated stainless steel pin were tested for their in vivo corrosion behavior. Six paired samples of titanium and gold-plated pins were placed in box preparations of 12 periodontally involved premolars. Half of the samples were restored with a high copper admixed type amalgam while the rest were restored with a BisGMA-POCl2 bonding resin and a hybrid visible light-cured composite resin. After 3 months in vivo, the teeth were extracted, and the pins were removed and examined with an electron microprobe. The surface of the titanium pins was found to be smooth and without defects. Only traces of Ca and P could be identified from dentin. The gold-plated pins demonstrated cracks and pores, especially at the outer part of the serrations, resulting in disruption of the electroplated film. Traces of Hg, Sn, Cu, S, Zn, Ca, K, Cl, P, and S were detected at the gold-plated pin/amalgam interface, while Cl and P were found at the gold-plated pin/composite resin interface. The in vivo corrosion resistance of the titanium pins was found to be superior to that of the gold-plated stainless steel pins.

Calcium↗
PubMed1993

Mechanical properties of laser welds of titanium in dentistry by pulsed Nd:YAG laser apparatus.

The use of titanium in dentistry is increasing, and an adequate method of joining titanium units of restorations is needed. This study examined the welding of titanium with a normal pulse Nd:YAG laser. Laser welding of titanium was effective when performed in an argon atmosphere. ANOVA for the three-point bending test showed a correlation between the bending strength of a weld, the atmosphere under which the irradiation is performed, and the intensity of the irradiation.

Analysis of Variance↗