Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Titanium”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,441 records · Page 80Linked to original sources
PubMed2006

An ultra-clean firn core from the Devon Island Ice Cap, Nunavut, Canada, retrieved using a titanium drill specially designed for trace element studies.

An electromechanical drill with titanium barrels was used to recover a 63.7 m long firn core from Devon Island Ice Cap, Nunavut, Canada, representing 155 years of precipitation. The core was processed and analysed at the Geological Survey of Canada by following strict clean procedures for measurements of Pb and Cd at concentrations at or below the pg g(-1) level. This paper describes the effectiveness of the titanium drill with respect to contamination during ice core retrieval and evaluates sample-processing procedures in laboratories. The results demonstrate that: (1) ice cores retrieved with this titanium drill are of excellent quality with metal contamination one to four orders of magnitude less than those retrieved with conventional drills; (2) the core cleaning and sampling protocols used were effective, contamination-free, and adequate for analysis of the metals (Pb and Cd) at low pg g(-1) levels; and (3) results from 489 firn core samples analysed in this study are comparable with published data from other sites in the Arctic, Greenland and the Antarctic.

Air Pollutants↗
PubMed1993

Nickel-titanium spring properties in a simulated oral environment.

A study of nickel-titanium springs was undertaken to determine whether their mechanical properties are affected by prolonged exposure to a static, simulated oral environment. Stainless steel springs and polyurethane elastic chains were also studied for comparison. The springs were elongated to twice their rest length and held at that length while immersed in artificial saliva at body temperature for 0, 2, 4 or 6 weeks. Plots of force vs. deformation were made as the springs were stretched from rest length to three times that length and then relaxed back to rest. Nickel-titanium springs suffered no degradation of their spring properties in the simulated oral environment. In contrast, stainless steel springs became slightly more compliant to stretching, and polyurethane elastics lost a large portion of their force-generating capacity. These findings confirm and extend earlier reports which indicate that nickel-titanium is a preferred material for many orthodontic applications.

Dental Alloys↗
PubMed2004

Severe anterior open-bite case treated using titanium screw anchorage.

Anterior open bite is often caused by a downward rotation of the mandible and/or by excessive eruption of the posterior teeth. In such cases, it is difficult to establish absolute anchorage for molar intrusion by traditional orthodontic mechanics. This article reports the successful treatment of a severe skeletal anterior open-bite case using titanium screw anchorage. A female patient 33 years eight months of age had open bite of -7.0 mm and increased facial height. The titanium screws were implanted in both the maxilla and the mandible, and an intrusion force was provided with elastic chains for 13 months. After active treatment of 19 months, her upper and lower first molars were intruded about 3.0 mm each, and good occlusion was achieved. Her retrognathic chin and convex profiles were improved by an upward rotation of the mandible. Our results suggest that titanium screws are useful for intrusion of molars in anterior open-bite cases.

Adult↗
PubMed2003

Tissue response to titanium implantation in the rat maxilla, with special reference to the effects of surface conditions on bone formation.

Tissue responses to titanium implantation with two different surface conditions in our established implantation model in rat maxillae were investigated by light and transmission electron microscopy and by histochemistry for tartrate-resistant acid phosphatase (TRAPase) activity. Here we used two types of implants with different surface qualities: titanium implants sandblasted with Al2O3 (SA-group) and implants coated with hydroxyapatite (HA-group). In both groups, bone formation had begun by 5 days postimplantation when the inflammatory reaction had almost disappeared in the prepared bone cavity. In the SA-group, however, the bone formation process in the bone cavity was almost identical to that shown in our previous report using smooth surfaced implants (Futami et al. 2000): new bone formation, which occurred from the pre-existing bone toward the implant, was preceded by active bone resorption in the lateral area with a narrow gap, but not so in the base area with a wide gap. In the HA-group, direct bone formation from the implant toward the pre-existing bone was recognizable in both lateral and base areas. Many TRAPase-reactive cells were found near the implant surface. On the pre-existing bone, new bone formation occurred with bone resorption by typical osteoclasts. Osseointegration around the implants was achieved by postoperative day 28 in both SA- and HA-groups except for the lateral area, where the implant had been installed close to the cavity margin. These findings indicate that ossification around the titanium implants progresses in different patterns, probably dependent on surface properties and quality.

Acid Phosphatase↗
PubMed2000

An in vitro comparison of canal preparation using two automated rotary nickel-titanium instrumentation techniques.

AIM: The aim of this study was to compare the efficacy of root canal preparation using two automated rotary nickel-titanium instrumentation techniques with a double flared balanced forces hand preparation technique, using stainless steel files in extracted human teeth. METHODOLOGY: Sixty root canals in extracted human teeth were matched for curvature, length and diameter and divided evenly between three groups (group 1 = double flare using Flexofiles, group 2 = rotary nickel-titanium using McXIM instruments and group 3 = rotary nickel-titanium using Profile .04 Taper Series 29 instruments). The instruments were used according to the manufacturer's instructions in a torque controlled motor and handpiece (groups 2 and 3) and according to a predetermined procedure in group 1. A standardized radiographic technique using mercury as a contrast medium was used to evaluate the canal shape before and after preparation in the plane of maximum curvature. The pre- and postoperative radiographic images were compared against each other and with a predicted 'ideal preparation' calculated from a projection of the final instrument dimensions. The outcome measures were changes in canal dimensions as quantified by measuring the changes in the position of the inner and outer wall at 1 mm intervals. Alteration in canal curvature could be inferred by comparison with the ideal preparation. RESULTS: The degree of canal curvature did not influence the effectiveness of any of the techniques. The results showed no statistically significant differences in the outcome measures between the groups (two-way ANOVA). There were no significant differences in canal wall position changes at any level except the apical three, where significantly less change occurred in all groups (P = 1%). Instruments fractured in three canals, with acute curves in groups 2 and 3. CONCLUSIONS: Canal curvatures were equally and well maintained following preparation in all the groups, as long as the instrument did not fracture.

Analysis of Variance↗
PubMed2001

The use of computed tomography when comparing nickel-titanium and stainless steel files during preparation of simulated curved canals.

AIM: The aim of this study was to compare canal preparations completed with Hedstrom and K-files of ISO size 15 - 40, made of nickel-titanium (Ni-Ti) and stainless steel (SS). METHODOLOGY: Eighty simulated canals with 200 and 30 degrees C curvatures were prepared using the step-back technique and quarter turn/pull instrument manipulation. Middle and apical level canal sections were taken using computed tomography. RESULTS: No significant difference was found between any of the file types at either level with respect to canal curvature (20 degrees or 30 degrees). At the middle level, the stainless steel files caused more enlargement toward the inner part, compared to nickel-titanium files. At the apical level, nickel-titanium canal files caused more enlargement toward the inner part, whereas more outward enlargement was caused by stainless steel instruments. No significant difference could be observed at the middle level (P > 0.05) related to the enlargement toward the outer side of the canal curvature. Transportation at both levels was significantly less (P < 0.001) for the Ni-Ti files than the SS ones. Centring ratios of the file types at the middle level were low, but not significantly different (P > 0.05), whereas at the apical level the centring ratios were significantly higher for the Ni-Ti files (P < 0.001). CONCLUSIONS: Ni-Ti instruments produced preparations with adequate enlargement, less transportation, and a better centring ratio.

Dental Instruments↗
PubMed1997

Bonding of titanium with acidic primers and a tri-n-butylborane-initiated luting agent.

Adhesive bonding of titanium was investigated with the use of five primers and two luting agents. All of the primers contained acidic methacrylate monomers for promotion of metal bonding. Titanium metal specimens were bonded with seven combinations of five primers and two luting agents. Durability of the bond was evaluated by means of thermocycling. Although all five primers enhanced the bond strength to titanium, three of the primers (Super-Bond Liquid, Metal Primer and Tokuso Rebase MR. Bond) demonstrated more durable bonds than the other two primers (Acryl Bond and All-Bond 2 Primer B). The tri-n-butylborane (TBB)-initiated luting agent exhibited better bonding ability as compared to conventional composite resin. The strongest and the most consistent bond was achieved by the combination of 4-methacryloyloxyethyl trimellitate anhydride (4-META) primer and TBB resin.

Acids↗
PubMed1999

Investigation of microleakage between titanium and porcelain.

Porcelain was applied to 30 titanium and 30 Remanium CS disc-shaped frameworks in order to investigate the microleakage. Each group was divided to three subgroups each containing 10 specimens and representing the different firing cycles (10 specimens for opaque + dentine; 10 specimens for opaque + dentine + enamel; and 10 specimens for opaque + dentine + enamel porcelain + glaze application). All the specimens were stored in 37 degrees C distilled water for 2 weeks and subjected to 100 thermocycles between 5 and 55 degrees C with 30 s dwell time. The specimens were then stored in 5% basic fuchsin dye for 2 days. The washed, rinsed and air dried specimens were embedded in autopolymerizing resin and sectioned diametrically. The stereoptical investigations were performed by three independent investigators. The data were analysed by the Mann-Whitney U-test. The statistical analysis revealed that the different number of firings does not affect the amount of microleakage. However, it should be emphasized that the use of titanium would be beneficial regarding the relatively lower values obtained from the titanium-porcelain group.

Dental Leakage↗
PubMed2001

Marginal adaptation of cast partial crowns made of pure titanium and a gold alloy under influence of a manual burnishing technique.

The aim of this study was to determine the marginal adaptation of partial crowns from pure titanium and a gold alloy after two different cementation techniques. Forty freshly extracted human molars were prepared and randomly divided in four groups. Two groups were restored with partial crowns using the gold alloy Degulor M*. In one group, the crowns were fixed on the tooth by using a zinc phosphate cement. In the other group the margins were additionally burnished by using a hand burnisher No. 660. In the other two groups, partial crowns from pure titanium were cemented in the same way. The marginal quality was determined by quantitative margin analysis in the SEM using a replica technique. Partial crowns from a gold alloy showed significantly (P < 0.05) more margin quality A (vertical marginal discrepancy < 50 microm) while partial crowns from pure titanium had significantly (P < 0.05) more margin quality B (vertical marginal discrepancy 50-100 microm) and over-extended margins (quality D). No significant (P < 0.05) difference was found between the conventional cementation technique and the technique with manual burnishing in both material groups.

Cementation↗
PubMed2002

Adhesive bonding of composite material to cast titanium with varying surface preparations.

The purpose of the present study was to evaluate the surface preparation effects of eight metal conditioners and an adhesive system on bonding between a prosthodontic composite material and cast titanium. Eight primers designed for conditioning base metal alloys (Acryl Bond, All-Bond 2 Primer B, Alloy Primer, Cesead II Opaque Primer, Eye Sight Opaque Primer, Metafast Bonding Liner, Metal Primer II, and MR Bond) as well as a surface modification technique (Siloc) were assessed. Disk specimens cast from titanium (T-Alloy H) were either primed with one of the eight primers or treated with the Siloc system, and then bonded with a light-activated composite material (Artglass). Bond durability was evaluated by thermocycling (4 and 60 degrees C, 1 min each, 20, 000 cycles). After thermocycling, two groups either primed with the Cesead II Opaque Primer material or treated with the Siloc system exhibited significantly greater bond strength (20.0 and 19.0 MPa) than the other groups (0.2-12.6 MPa, P < 0.05). These two systems are considered to be useful for improving bonding between the titanium and the composite material tested.

Adhesives↗
PubMed2001

Strength analysis of Le Fort I osteotomy fixation: titanium versus resorbable plates.

PURPOSE: The purpose of this study was to compare the biomechanical characteristics of metallic and polymeric fixation systems using a 3-dimensional skull model to simulate clinical conditions of maxillary advancement and loading. MATERIAL AND METHODS: Standard titanium, prebent titanium, and resorbable plates and mesh were applied to surgically altered polyurethane skulls. The constructs were loaded using an Instron machine (Instron Inc, Canton, MA) in anterior-posterior (AP) and inferior-superior (IS) directions. The load displacement, load to failure, and deformation magnitudes and modes of failure were recorded. Statistical studies included analysis of variance (ANOVA) at P <.05. RESULTS: Elastic stiffness was different among groups in the AP direction, but no significant difference was found in the IS direction. The IS loading direction load displacement (stiffness) was significantly greater than that on AP loading. The maximum load for permanent deformation was larger in the AP direction, while the maximum load for breaking was larger in the IS direction. CONCLUSION: The overall evaluation of the model and test analyses supported the relative value of this in vitro system and study procedure. All systems showed load capacity magnitudes above 285 N (64 lbs) and more elastic resistance in the IS direction. The resorbable systems showed lower elastic stiffness compared with the titanium systems, but they appear to be adequate for fixation and withstanding the forces of mastication.

Absorbable Implants↗
PubMed2000

Serum titanium level for diagnosis of a failed, metal-backed patellar component.

A case is presented in which an elevated serum titanium level was used to make the diagnosis of a failed metal-backed patellar component. The preoperative serum titanium level was 536.8 ppb, which was 98 times higher than the patient's previous level (taken 1 year earlier, when he was asymptomatic) and 2 orders of magnitude higher than the expected level with a well-functioning implant of this type. Revision surgery confirmed that the polyethylene portion of the patellar component had worn through, leaving the titanium portion of the patellar implant to articulate with the femoral component. Wear-through was not evident on preoperative radiographs or clinical examination. As knowledge about the expected ranges for serum metal ion levels after total joint arthroplasty continues to increase, the diagnostic utility of serum metal ion testing in the evaluation of joint arthroplasty function will continue to improve.

Aged↗
PubMed1999

[The x-ray follow-up study of the cervical spine after anterior fusion with titanium disk implants].

PURPOSE: We examined the postoperative changes of the cervical spine after treatment of cervical nerve root compression with anterior cervical discectomy and fusion with a new titanium intervertebral disc. PATIENTS AND METHODS: 37 patients were examined prior to, as well as 4 days, 6 weeks, and 7 months after surgery. Lateral view X-rays and functional imaging were used to evaluate posture and mobility of the cervical spine, the position of the implants, and the reactions of adjacent bone structures. RESULTS: Implantation of the titanium disc led to post-operative distraction of the intervertebral space and slight lordosis. Within the first 6 months a slight loss of distraction and re-kyphosis due to impression of the implants into the vertebral end-plates were found in all patients. We noted partial infractions into the vertebral end-plates in 10/42 segments and slight mobility of the implants in 14/42 segments. Both groups of patients showed reactive spondylosis and local symptoms due to loosening of the implants. The pain subsided after onset of bone bridging and stable fixation of the loosened discs. CONCLUSIONS: The titanium intervertebral disc provides initial distraction of the fusion segments with partial recurrence of kyphosis during the subsequent course. Loosening of the implants with local symptoms can be evaluated with follow-up X-rays and functional imaging.

Adult↗
PubMedDate not supplied

[10 year results with a cemented fine-grit-blasted titanium-aluminum-vanadium hip endoprosthesis shaft].

PURPOSE: Are the results of cemented titanium hip arthroplasty as bad as described in literature? We present the 10-year results of a cemented mild grid blasted Titanium-Aluminium-Vanadium Stem in Total-Hip-Arthroplasty. METHODS: The clinical and radiological reexamination was documented in standardized questionnaire in which several scores were integrated. All X-rays were stored and analysed by a special hardware and software computer system. RESULTS: 35% of all patients could be reexamined both clinically and roentgenologically. 71 patients were male (mean age 56.1 years) and 130 female (mean age 59.3 years). The average follow-up period was 11 years and 4 months. The mean Merle d'Aubigné hip score increased from 10.5 to 16.0 points at the follow-up evaluation. Radiolucent lines were according to the zones of Gruen seen in 1% to 22% depending on the zone and the size of the femoral component. 18 reoperations of the femoral component (2.9%) had to be performed. The survivorship analysis (Kaplan-Meier) showed a 95.4% survival of the femoral component after 10 years. CONCLUSION: Our findings with a cemented mild grid blasted Titanium-Aluminum-Vanadium stem demonstrate excellent results unlike it was reported for cemented femoral components of similar alloy but different design and cementation philosophy.

Alloys↗
PubMedDate not supplied

[Cytokine profile of a human bone marrow cell culture on exposure to titanium-aluminium-vanadium particles].

INTRODUCTION: The purpose of this study was to prove the effect of wear particles, especially Tivanium, in the mechanism of the aseptic loosening of total joint prostheses. MATERIALS AND METHODS: Therefore, human bone marrow cell cultures were incubated with titanium-aluminium-vanadium particles of different concentrations which were added after the seventh day of culture (10(9), 10(8), 10(7), 10(6) particles per ml medium). From this time starts the real culture period (2 weeks). During these two weeks the medium was changed and the supernatants were sampled. Using an ELISA the cytokine levels of interleukin-6, interleukin-1beta, TNF-alpha and LDH were measured approximately every second day (1, 3, 6, 8, 10, 14). As a marker for toxicity the activity of LDH was determined. RESULTS: Incubation of a human bone marrow cell culture with titanium-aluminium-vanadium particles led to a maximum release of interleukin-6, interleukin-1beta, and TNF-alpha at high particle concentration (10(9) particles per ml medium). An increase of interleukin-1beta was only detectable at particle concentrations of 10(9) per ml medium. Exposure of the human bone marrow cell culture to titanium-aluminium-vanadium particles was toxic for high particle concentrations (10(9) particles per ml medium), as reflected by release of the intracellular enzyme LDH. DISCUSSION: This study shows the ability of tivanium wear particles in a human bone marrow cell culture to induce a signfically higher release of proinflammatory and osteolytic mediators which are responsible for the aseptic loosening of prosthesis and the problem of revisions. In comparison to other cell studies, our results were explained by the human bone marrow cell culture. The human bone marrow is the real effector tissue source "in situ" because the prosthesis is localised intramedullarly.

Adult↗
PubMedDate not supplied

[Biomechanical study on lumbar spondylodeses using an internal fixateur consisting of a titanium alloy].

OBJECTIVE: Biomechanical properties of an internal fixateur manufactured of a titanium alloy (Ti-6Al-4V-alloy) to be evaluated in an in vitro setting. METHOD: Internal fixateurs were inserted into six (four female and two male specimens) human lumar spine segments L2 to L4. Only dorsal instrumentations were performed. Physiological loads were applied (2.0 to 10.0 Nm for torque, 2.0 to 7.5 Nm for extension/flexion and lateral bending). Biomechanical investigations were performed in four settings: Intact specimen without instrumentation, instrumented specimen, instrumented specimen after corpectomy of the middle vertebral body, instrumented specimen after corpectomy of the middle vertebral body with an additional transverse connector. RESULTS: Stability after instrumentation was increased by 84.7 % for flexion/extension, by 78.2 % for lateral bending and by 43 % for axial torsion. Axial torsion was already less distinct in the physiological specimen. The stability of instrumented specimen after corpectomy was superior to that of intact vertebral segments without internal fixation. Additional application of transverse connectors did not significantly enhance the stiffness of the implant. CONCLUSION: For the clinical use there is no difference in the biomechanical properties of the titanium fixateur compared to similar constructions made of stainless steel. The possibility of performing MRI- or CT-scans after implantation of titanium implants is a main clinical advantage. The stabilisation after corpectomy is remarkable, so that a sufficient fracture-stabilisation is possible. Based on the data, the application of transverse connectors cannot be recommended.

Adult↗
PubMed1999

[Three years of experience with titanium implants in the middle ear].

BACKGROUND: In continuation of our previously published report on initial experience with titanium implants in the middle ear [13], we now present the results of routine use over a three year period. METHODS: From November 1994 to November 1997, 661 titanium implants (Düsseldorf model) were implanted in the authors' clinics (355 PORP, 306 TORP). There was no preselection of patients. Five hundred eighty-two follow up examinations were performed with a medium follow up time of 11.6 months. RESULTS: The good initial results of the previous study with respect to biocompatibility and functional hearing results were confirmed in the long term follow-up. The average air-bone gap was calculated over the frequencies 0.5, 1, 2, and 4 kHz. Closure to within 20 dB was achieved in 72% of cases. The air-bone gap tended to decrease with increasing time of implantation. Adverse reaction to the prostheses did not occur. Extrusion occurred in one case of complete middle ear atelectasis with resorption of the interposed cartilage. Insufficient improvement of hearing was attributable to a short implant in 12 cases (1.8%). In three cases (0.5%) insufficient stability of the PORP was attributable to eroded stapes suprastructure, and in three others (0.5%) a dislocation was responsible for a poor hearing result. Middle ear fibrosis with impairment of sound transmission was seen in 3 patients (0.5%). CONCLUSION: The superior acoustic properties of the delicate yet rigid low-weight titanium implants combined with excellent biocompatibility lead to a good hearing result if a meticulous surgical technique is employed. The easy handling makes it a pleasure to work with these protheses.

Ear, Middle↗
PubMedDate not supplied

[Osseointegration of a laser-structured titanium hemispheric acetabulum in the animal experiment].

Eight hemispherical titanium-cups with a new laser structured surface had been implanted in sheeps. Duration of implantation was eight weeks and one year. Analysis and evaluation of the results were done by post-operative x-rays, x-rays of the specimen, macroradiography, microradiography, fluorescencemicroscopy and histology. A quantitative analysis of the bony ingrowth was performed with a computer-aided system. The 8 weeks-cups showed an osseointegration rate of 28.8%, the one year group of 52.1% of the available surface. Bony ingrowth of the laserstructured titanium surface is possible. The laserstructured titanium surface can be used for the cementless fixation of implants.

Acetabulum↗