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PubMed2002

Titanium casting into phosphate bonded investment with zirconite.

OBJECTIVE: Reaction layer structure of the titanium castings surface was investigated when a new centrifuge-vacuum-pressure cast titanium machine and a zirconite inner investment was used. METHODS: The micro-hardness of titanium castings was measured using a Knoop's hardness tester. The structure of reaction layers and the distribution of elements on the surfaces of titanium castings were analysed by SEM and EDS, respectively, when zirconite was used as the inner investment for cast titanium. RESULTS: Knoop's micro-hardness at distances of 50 and 75 microm from the titanium casting surfaces made directly in phosphate investment molds had significantly harder surfaces than those made in zirconite coating molds. The thickness of the reaction layer on the surface of titanium castings was <35 microm with zirconite coating and was >50 microm without zirconite coating. The structure of reaction layer was divided into four layers from the outer surface to the inner including: sintering layer, alpha-Case, Si-rich layer, acicular crystal structure. The distribution of elements was different on each layer. SIGNIFICANCE: The thickness of the cast titanium reaction layer was reduced when the wax patterns were coated with zirconite. The surface of the titanium castings was smooth and without cracks, and the investment on the surface of titanium castings was easily removed.

Dental Casting Investment↗
PubMed1999

In vitro corrosion resistance of titanium made using different fabrication methods.

The corrosion of cast or milled ASTM Grade II CP titanium with different surface conditions was studied by potentiodynamic anodic polarization and immersion testing. Specimens were fabricated using three dental titanium casting systems and from machined titanium. Three surface conditions were tested: (1) sandblasted with surface reaction layers remaining; (2) polished surface without surface reaction layers; and (3) sandblasted surface without surface reaction layers. An acidic saline solution (0.1 M lactic acid/0.1 M NaC1 [pH = 2]) and an artificial saliva were used as the corrosion media. Anodic polarization was performed starting at 50 mV below the rest potential and terminating at +2250 mV vs Ag/AgCl. Two surface conditions (sandblasted with the surface reaction layers and polished without such layers) were examined in the immersion test. Specimens were immersed in the corrosion media at 37 degrees C for six months. The recovered solution was analyzed by an atomic absorption spectrophotometer for titanium dissolution. A distinctive passive region on the polarization diagram, ranging from approximately 0 to approximately +1300 mV, was observed for all specimens in both media. Great similarity was observed for all the sandblasted specimens which had larger primary passive current densities and passive regions compared to the polished ones. A current density peak at approximately +1600 mV seen for all the specimens with sandblasted surfaces was less well defined for the polished specimens. Immersion testing in the acidic saline solution revealed no significant differences among the polished specimens. A significant increase (P < 0.05) in titanium dissolution was found for the sandblasted specimens with surface reaction layers remaining on the surfaces made with phosphate-bonded SiO2/Al2O3 investment compared to the polished ones. Significant differences were also found between sandblasted specimens with the surface reaction layers resulting from different investment materials and different casting methods. Measurable amounts of titanium were not found for all specimens in the artificial saliva after six months. It is evident that the corrosion behavior of cast CP titanium is similar to that of machined titanium. The surface roughness appears to be a more prominent factor than do the surface reaction layers on the polarization behavior of the CP titanium under the present experimental conditions. Surface roughness and the presence of the surface reaction layers both affect the dissolution of titanium.

Biocompatible Materials↗
PubMed1999

Biologic response to passive dissolution of titanium craniofacial microplates.

The effect of anodization on passive dissolution of titanium was studied by measuring titanium levels in peritoneal leukocytes and tissues of laboratory animals with titanium plates implanted into the peritoneal cavity. Fifteen Sprague-Dawley rats were assigned randomly to three treatment groups of five animals. One group served as controls, the other two groups had an anodized or an unanodized implant placed in the left paracolic gutter. Peritoneal lavage samples and blood samples, organ tissues and tissue surrounding the implants, were removed for histologic examination and titanium levels. Titanium was not detected in any distant organs or in the peritoneal lavage fluid. The capsular tissues surrounding the implants contained titanium at levels ranging from 2610 to 16786 ng/g for unanodized plates, and 888-5933 ng/g for anodized plates. The titanium levels within the peritoneal leukocytes of animals with unanodized implants were significantly elevated (P = 0.01) over time, as compared with controls. The level of titanium in the peritoneal leukocytes of animals with anodized implants was not significantly elevated when compared with controls. Titanium levels in the trace range, as measured in the capsular tissues, are likely a result of corrosion. Surface treatment of titanium by anodization reduces passive dissolution.

Animals↗
PubMed2000

Determination of titanium dioxide in foods using inductively coupled plasma optical emission spectrometry.

Titanium dioxide is a common food additive of increasing interest in dietary intake studies and dietary exclusion studies. Food labelling for titanium dioxide is imprecise so a method was developed for its rapid determination in foods using acid digestion and inductively coupled plasma optical emission spectrometry (ICPOES). Twenty-five foods thought to contain titanium dioxide were obtained. Based on preliminary digestion studies, samples (500 mg) were digested in 18 mol l-1 H2SO4 at 250 degrees C for 1 h and then diluted to 5.9 mol l-1 H2SO4 before determination of titanium by ICPOES at 336.121 nm. Emission intensity was suppressed by H2SO4 so standards were matched for acid concentration. Titanium dioxide embedded in gelatine was used to assess accuracy. A standard reference material of known titanium concentration and six foods of known titanium dioxide content were used as external reference materials. Limits of detection were 2-7.5 ppb, depending on spectral integration times, and the signal was linear up to 5 ppm. Results for all control samples were in good agreement with the expected values. Twelve of the foods contained detectable titanium, ranging from 0.001 to 0.782% by weight, but only eight indicated this on their labels, four being exempt under food labelling regulations. Based on food portion sizes, an individual's daily intake of titanium dioxide could exceed 200 mg from just one of these products. This method may facilitate future studies on titanium dioxide intake, given the present limitations of food labelling.

Food Additives↗
PubMed2002

In vitro wear assessment of titanium alloy teeth.

PURPOSE: Wear of commercially pure (CP) titanium prosthetic teeth has frequently been observed. The greatest wear has been found when the same grades of CP titanium are used for both maxillary and mandibular teeth. This study examined the wear behavior of teeth made with cast titanium alloy and compared these results with those for CP titanium and gold alloy teeth. MATERIALS AND METHODS: All tooth specimens were cast with grade 3 alpha titanium, 3 metastable beta alloys [Ti-15Mo-2.8Nb-0.2Si (Timetal 21 SRx), Ti-13Nb-13Zr, and Ti-15V-3Cr-3Sn-3Al], and 2 alpha+beta alloys (Ti-6Al-7Nb and Ti-6Al-4V). As a control, Type IV gold alloy was also cast conventionally. All teeth (both maxillary and mandibular) were secured in an in vitro 2-body wear testing apparatus that simulated chewing function (60 strokes/min; grinding distance, 2 mm under flowing water). Wear resistance was assessed as volume loss (mm(3)) at 5 kgf (grinding force) after 50,000 strokes. The results (n = 5) were analyzed using analysis of variance or Fisher's exact test (alpha = 0.05). RESULTS: Of the titanium teeth, the wear of 2 of the metastable beta alloys (Timetal 21 SRx and Ti-15V-3Cr-3Sn-3Al) was found to be significantly (p <0.05) higher than that of CP titanium and the 2 alpha+beta alloys. The Type IV gold alloy exhibited better wear resistance than all of the titanium teeth tested. No correlation was found between wear loss and hardness among all the metals tested. CONCLUSIONS: Among the titanium teeth examined, the alpha+beta alloys exhibited significantly less wear than the other types of titanium. The dental casting gold alloy tested exhibited the best wear resistance among all of the metals tested.

Alloys↗
PubMed2002

[Results after rebuilding the ossicular chain using the autogenous incus, ionomer-cement-and titanium implants (tympanoplasty type III)].

BACKGROUND: A defective ossicular chain can reliably be reconstructed with standardized techniques using e. g. modern alloplastic materials. The comparison of clinical and functional results have proved its worth. Prospective clinical trial as well as collecting and evaluating relevant intraoperative and postoperative findings may be helpful to find the appropriate bone substitute in each case when rebuilding middle ear structures. METHOD: In 354 middle ears (332 patients) the defective or destroyed ossicular chain was rebuilt with the carefully trimmed autogenous incus (n = 83), with ionomer-cement implants (n = 100) and with titanium prostheses (n = 171). The follow-up of the earmicroscopic findings and middle ear function extended over a period of 1.5 years postoperatively on an average (min. 3 months, max. 6 years). The modified otologic record form named "Würzburger Ohrbogen" was used for preoperative and operative data, the "Ohrnachsorgebuch" for the postoperative follow-up. RESULTS: Using incus the air bone gap was improved up to 15 dB in the main speech area. Thus the average remaining conduction deficit was less than 10 dB. The "taking" of ionomer based cement prostheses and titanium prostheses was equally good. The cement implants showed a tendency to protrusion (n = 3), 2 titanium implants were extruded. The air bone gap decreased about 10 to 35 dB using titanium total prosthesis and about 15 to 20 dB using ionomer-cement total prosthesis. The remaining air bone gap with titanium implants was slightly less than with the ionomer-cement PORP (10-15 dB). The air bone gap using the titanium TORP was diminished in a reach of 10 to 35 dB, with the ionomer cement prosthesis between 15 to 20 dB. The remaining gap in the main speech area was slightly favorable to titanium (less than 15 dB) compared with the ionomer-cement TORP. Comparing higher frequencies the air bone gap of titanium was recognizable due to its light weight, but less impressive than expected. Revision surgery (n = 50) has to be performed by reason of cholesteatoma (n = 9), adhesive process (n = 8), dislocation of alloplastic prostheses (n = 8) and because of proposed "second look" (n = 14). CONCLUSIONS: Compared with other materials autogenous implants used for reconstruction of the incus have proved their value, however a deterioration of the sound transmission may develop in the long run. The middle ear compatibility of ionomer-cement implants is similar to titanium implants. The functional results of the titanium implants seem to be slightly superior.

Adolescent↗
PubMed2007

PMMA versus titanium cage after anterior cervical discectomy - a prospective randomized trial.

INTRODUCTION: Nonautologous interbody fusion materials are utilised in increasing numbers after anterior cervical disc surgery to overcome the problem of donor site morbidity of autologous bone grafts. This study investigates the performance of two nonautologous materials, the bone cement Polymethylmethacrylate (PMMA) and titanium cages. This prospective randomised trial, with assessment of the results by an independent observer, evaluates whether a Polymethylmethacrylate (PMMA) spacer or a titanium cage provides a better fusion rate around the implant and a better clinical outcome. PATIENTS/MATERIAL AND METHODS: Between 2000 and 2002, 115 patients with monoradicular cervical nerve root compression syndrome caused by soft cervical disc herniation were eligible for this study. Myelopathy, excessive osteophyte formation, and adjacent level degeneration were exclusion criteria. A block-restricted randomisation was applied. The 2-year clinical outcome served as the primary endpoint of the study. Clinical outcome was assessed according to the Odom scale by an independent observer at the follow-up examination. Preoperative, postoperative, and follow-up radiographs were taken. RESULTS: The study was completed by 107 patients (53 with PMMA and 54 with titanium cage). No significant difference between the two groups could be established with respect to the clinical outcome. In each group, 26 patients scored excellent. Good results were found in 19 PMMA patients and 16 titanium cage patients; satisfactory results were found in 8 PMMA patients and 9 titanium cage patients; bad results were found in 3 titanium cage patients. In 47 titanium cage cases (87%), fusion occurred radiologically as bony bridging around the implant. The fusion rate was significantly lower (p=0.011) in the PMMA group, with 35 cases (66%) united at follow-up. CONCLUSION: The radiological result of the titanium cage is superior to that of PMMA with respect to the fusion rate. Although the titanium cage achieves a better fusion rate, there is no difference between titanium cages and PMMA with respect to the clinical outcome.

Adolescent↗
PubMed2002

Safety of titanium mesh for orbital reconstruction.

During the past several decades, the standard of care for orbital reconstruction after trauma has been autogenous bone grafts. Complications of bone grafts, including donor site morbidities such as scar alopecia and graft resorption with delayed enophthalmos, have inspired an interest in the use of alloplastic substitutes such as titanium. Titanium's role in orbital reconstruction was limited originally to small orbital defects, and as an adjunct to bone grafts. More recently, clinical studies have documented the sole use of titanium mesh to reconstruct large orbital defects. This study sought to document further the safety and efficacy of titanium mesh in reconstructing large orbital defects after facial trauma, with more extensive follow-up compared with previous studies. In the current study, 55 patients with 67 orbital fractures underwent orbital reconstruction with titanium mesh over a 5-year period. Associated fractures were reduced anatomically and fixed rigidly. For the analysis, 44 patients with 56 orbital fractures had adequate follow-up (mean, 44 months). An abscess developed in one patient who received high-dose steroids for 72 hours before reconstruction. She was treated with broad-spectrum intravenous antibiotics and bedside incision and drainage, and did not require removal of the titanium mesh. No patient in the current series required removal of the titanium mesh. A single case of uncorrected enophthalmos was treated with bone grafting rather than mesh revision. Large orbital defects can be reconstructed using titanium mesh with good functional results and minimal risk for infection. This study covered the authors' first 5 years using titanium. They have now used titanium mesh in orbital reconstructions for more than 10 years, without any additional cases of infection.

Adolescent↗
PubMed1998

A comparison of magnetic resonance and computed tomographic image quality after the implantation of tantalum and titanium spinal instrumentation.

STUDY DESIGN: Tantalum- and titanium-based lumbar interbody fusion devices were implanted into two fresh human cadavers, and magnetic resonance and computed tomographic imaging were performed to evaluate adjacent spinal structures and the amount of metallic artifact. OBJECTIVE: The objective of this study was to prospectively compare the preliminary results of magnetic resonance imaging and computed tomography scanning image quality after the implantation of both titanium and tantalum spinal implants. SUMMARY OF BACKGROUND DATA: The availability of tantalum and titanium spinal implants brings theoretical magnetic resonance imaging compatibility along with several other desirable characteristics. The magnetic resonance imaging and computed tomographic imaging of tantalum spinal instrumentation has never been studied previously or compared with titanium instrumentation. METHODS: Titanium and tantalum spinal implants produced for anterior spinal fusion were each placed at two levels in the lumbar spine of two fresh cadaver specimens. Sequential spin echo T1-weighted and T2-weighted magnetic resonance imaging studies and computed tomographic scans were obtained. The resulting images were then graded to describe and compare the behavior of tantalum metal in magnetic resonance imaging and computed tomographic studies. RESULTS: Good T1 and T2 images were obtained that allowed visualization of the neural structures with minimal artifact. The optimal T1 images for tantalum metal were similar in quality to the optimal T1 parameters for titanium metal. T2 images for both tantalum and titanium metal were obtained with similar results for both metals. Gradient echo magnetic resonance imaging scans of both were poorly imaged with a large amount of artifact. Computed tomographic studies of tantalum implants produced a large amount of metal artifact when compared with computed tomographic studies of titanium implants. CONCLUSIONS: High-quality magnetic resonance imaging studies can be obtained after the implantation of both titanium and tantalum spinal instrumentation. Both of the metals produce similar images on magnetic resonance imaging studies with comparable amounts of metallic artifact. High-quality computed tomographic scans of titanium implants can be obtained with minimal distortion secondary to artifact. However, computed tomographic scanning is not the imaging modality of choice for the tantalum spinal implants because of the large amounts of artifact.

Artifacts↗
PubMed2003

Metal concentrations in the serum and hair of patients with titanium alloy spinal implants.

STUDY DESIGN: A retrospective study of serum and hair metal concentrations in patients with titanium alloy spinal implants was performed. OBJECTIVE: To determine the incidence and possible causes of abnormal metal concentrations. SUMMARY OF BACKGROUND DATA: Several studies have demonstrated that metal debris are present in the tissues surrounding titanium alloy spinal implants. However, few studies suggest that metals dissolve, circulate in the body fluid, and accumulate in remote organs. METHODS: Titanium, aluminum, and vanadium concentrations in serum and hair were measured after surgery in 46 patients with titanium alloy spinal implants (12 patients in the implant failure group and 34 patients in the no implant failure group) and 20 patients without spinal implants (control group). All the subjects were examined again 1 year after the first examination or implant removal. RESULTS: Of the 46 patients with titanium alloy spinal implants, 16 patients (34.8%) exhibited abnormal serum metal concentrations and 11 patients (23.9%) exhibited abnormal hair metal concentrations. In the control group, three patients (15%) exhibited only abnormal serum and metal aluminum concentrations at the first examination. In both of the two patients who exhibited abnormal serum titanium concentrations and then had their spinal implants removed, the serum and hair titanium levels decreased to beneath the reference value limit in 1 year after the removal. Comparison of the implant failure and no implant failure groups showed no significant differences in the incidence of abnormal serum concentrations of titanium, aluminum, or both metals. Therefore, serum metal concentrations did not seem to be a useful indicator of hardware loosening or implant failure. CONCLUSIONS: Approximately one third of patients with titanium alloy spinal implants exhibited abnormal serum or hair metal concentrations at a mean time of mean 5.1 years after surgery. Titanium or aluminum may travel to distant organs after dissolution of metals from the spinal implants.

Adolescent↗
PubMed2005

The transmission of stress to grafted bone inside a titanium mesh cage used in anterior column reconstruction after total spondylectomy: a finite-element analysis.

STUDY DESIGN: A finite-element study of posterior alone or anterior/posterior combined instrumentation following total spondylectomy and replacement with a titanium mesh cage used as an anterior strut. OBJECTIVES: To compare the effect of posterior instrumentation versus anterior/posterior instrumentation on transmission of the stress to grafted bone inside a titanium mesh cage following total spondylectomy. SUMMARY OF BACKGROUND DATA: The most recent reconstruction techniques following total spondylectomy for malignant spinal tumor include a titanium mesh cage filled with autologous bone as an anterior strut. The need for additional anterior instrumentation with posterior pedicle screws and rods is controversial. Transmission of the mechanical stress to grafted bone inside a titanium mesh cage is important for fusion and remodeling. To our knowledge, there are no published reports comparing the load-sharing properties of the different reconstruction methods following total spondylectomy. METHODS: A 3-dimensional finite-element model of the reconstructed spine (T10-L4) following total spondylectomy at T12 was constructed. A Harms titanium mesh cage (DePuy Spine, Raynham, MA) was positioned as an anterior replacement, and 3 types of the reconstruction methods were compared: (1) multilevel posterior instrumentation (MPI) (i.e., posterior pedicle screws and rods at T10-L2 without anterior instrumentation); (2) MPI with anterior instrumentation (MPAI) (i.e., MPAI [Kaneda SR; DePuy Spine] at T11-L1); and (3) short posterior and anterior instrumentation (SPAI) (i.e., posterior pedicle screws and rods with anterior instrumentation at T11-L1). The mechanical energy stress distribution exerted inside the titanium mesh cage was evaluated and compared by finite-element analysis for the 3 different reconstruction methods. Simulated forces were applied to give axial compression, flexion, extension, and lateral bending. RESULTS: In flexion mode, the energy stress distribution in MPI was higher than 3.0 x 10 MPa in 73.0% of the total volume inside the titanium mesh cage, while 38.0% in MPAI, and 43.3% in SPAI. In axial compression and extension modes, there were no remarkable differences for each reconstruction method. In left-bending mode, there was little stress energy in the cancellous bone inside the titanium mesh cage in MPAI and SPAI. CONCLUSIONS: This experiment shows that from the viewpoint of stress shielding, the reconstruction method, using additional anterior instrumentation with posterior pedicle screws (MPAI and SPAI), stress shields the cancellous bone inside the titanium mesh cage to a higher degree than does the system using posterior pedicle screw fixation alone (MPI). Thus, a reconstruction method with no anterior fixation should be better at allowing stress for remodeling of the bone graft inside the titanium mesh cage.

Aged, 80 and over↗
PubMed1996

Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium.

The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival fibroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.

Alloys↗
PubMedDate not supplied

Influence of titanium coating on the biocompatibility of a heavyweight polypropylene mesh. An animal experimental model.

INTRODUCTION: In light of the fact that, to date, no information is available about titanium relative to its application in prosthetic material employed for hernial repair, the aim of the present work was to evaluate the fundamental possibilities of titanium-coated polypropylene meshes. MATERIALS AND METHODS: In experiments with animals, two groups, each containing 11 pigs, received either a heavyweight polypropylene mesh (Atrium) or an identical but titanium-coated mesh (titanium-coated Atrium) implanted into the left groin using the totally endoscopic extraperitoneal patchplasty technique. RESULTS: A significant difference in the shrinkage behavior between conventional Atrium and titanium-coated Atrium was found (14.9 vs. 8.8%, p < 0.05). Furthermore, the partial volume of the inflammatory infiltrate also proved to be smaller with the titanium-coated mesh (14.9 vs. 12.4%). In addition, Ki-67 expression was lower in the group implanted with titanium-coated mesh (21.0 vs. 15.0%). No difference was observed with regard to the apoptosis index (7.6 vs. 6.5). CONCLUSIONS: Heavyweight titanium-coated polypropylene meshes induce a less pronounced foreign body reaction in comparison with identical meshes with no titanium coating, which, since the amount of material implanted is identical, must be attributed solely to the titanium coating.

Animals↗
PubMed2001

Down-regulation of procollagen alpha1[I]] messenger RNA by titanium particles correlates with nuclear factor kappaB (NF-kappaB) activation and increased rel A and NF-kappaB1 binding to the collagen promoter.

Previously, we showed that exposure of human osteoblasts to titanium particles stimulates protein tyrosine phosphorylation (PTP), activates the transcription factor nuclear factor kappaB (NF-kappaB), and causes an approximately 50% decrease in the steady-state messenger RNA (mRNA) level of procollagen alpha1[I]. In this study, we identify three NF-kappaB binding sites within the human procollagen alpha1[I] gene promoter, show that titanium particles stimulate their binding of the NF-kappaB subunits Rel A (p65) and NF-kappaB1 (p50), and find NF-kappaB activation correlates with collagen gene suppression by titanium particles in osteoblasts. Protein tyrosine kinase (PTK) inhibitors, which significantly reduce the suppressive effect of titanium particles on collagen gene expression, inhibited NF-kappaB binding activity showing that titanium particle stimulation of PTK signals in osteoblasts are critical for both NF-kappaB activation and collagen gene expression. The antioxidant pyrrolidine dithiocarbamate (PDTC), which also inhibits the titanium particle suppression of collagen, abrogated the titanium particle activation of NF-kappaB, suggesting the involvement of redox signals in NF-kappaB-mediated collagen gene expression. The RNA polymerase II inhibitor actinomycin D (Act D) decreased procollagen alpha1[I] mRNA expression and effectively blocked the titanium-induced suppressive effect, suggesting that titanium particles activate a cascade of signals in osteoblasts, which result in a suppression of procollagen alpha1[I] mRNA. Collectively, these results show that titanium particles can activate NF-kappaB signaling in osteoblasts and suggest that NF-kappaB binding to the collagen gene promoter has a functional role in the down-regulation of procollagen alpha1[I] gene transcription.

Binding Sites↗
PubMed2006

Influence of titanium surface charge on fibroblast adhesion.

BACKGROUND: Although dental implants have a high success rate, failure owing to the absence of adhesion between the gingival connective tissue and the implant surface is still being reported. PURPOSE: This study was designed to evaluate the effect of a titanium surface charge on fibroblast adhesion. MATERIAL AND METHODS: An electrical chamber was custom-made to generate negative and positive surface charges on commercially pure titanium cylinders with a potential difference of 4.5 V. Twenty-seven titanium cylinders were divided into three experimental groups. In each group, cell attachment to a positively charged titanium cylinder, a negatively charged titanium cylinder, and a titanium cylinder (control) was studied at three time intervals of 15, 30, and 60 minutes. NCTC clone 929 fibroblasts were used in these experiments. The effect of the potential difference in the pH of Dulbecco's Modified Eagle Medium (DMEM) was also evaluated using two new specimens at time intervals of 15, 30, 60, and 80 minutes. RESULTS: The fibroblast cell attachment was more statistically significant to the positively charged titanium cylinder than the negatively charged titanium cylinder (p =.002) and the control (p=.000), whereas the cell adhesion difference between the control and the negatively charged titanium cylinder was not statistically significant (p=.808). The range of pH difference of the DMEM in the negative and positive parts of the electrical chamber was 0.46 and 0.30, respectively. CONCLUSION: Within the limitations of this in vitro study, the positive surface charge of the titanium cylinder results in significantly favorable cell adhesion.

Analysis of Variance↗
PubMed1993

[In vitro study on biocompatibility of zirconium and titanium].

The purpose of this study is to evaluate the biocompatibility of zirconium compared with titanium by the in vitro study using human osteosarcoma cell line (HOS). Various characteristics of the HOS cells cultured on zirconium (99.9%) and titanium (99.9%) discs were investigated. On the colony formation of the HOS cells, there were no differences between the zirconium and titanium in colony size and number. Good proliferation of the HOS cells was observed on the zirconium as well as on the titanium. Morphological observation of the HOS cells by SEM revealed that the cells on the zirconium as well as on the titanium were flat and polygonal in shape with radial pseudopods. Collagen fibers and calcified substances were observed in the matrix of the HOS cells by TEM on the zirconium as well as on the titanium. The calcium of the HOS cell layer was stained well by Dahl's method. Analysis of the HOS cell layer by the Fourier transform infrared spectroscopy indicated that the HOS cells formed the same matrices including the apatite on the zirconium as on the titanium. Measurements of the zirconium and titanium elution into the human saliva indicated that the elution of zirconium was less than that of titanium. These results suggest that zirconium possesses as excellent biocompatibility as titanium.

Biocompatible Materials↗
PubMed2005

On titanium frameworks and alternative impression techniques in implant dentistry.

PURPOSE: The objectives of this thesis were to compare the clinical and material performance of implant-supported titanium frameworks with gold-alloy frameworks in the edentulous jaw and to test a digitized impression technique to optimize material characteristics and clinical and laboratory procedures. MATERIALS AND METHODS: Two different kinds of laser-welded titanium frameworks and one type of digitized computer numeric controlled (CNC)-milled titanium framework for the edentulous jaw were evaluated and compared with gold-alloy frameworks in two clinical 5-year follow-up studies. The CNC frameworks were also evaluated and compared with gold-alloy frameworks in two experimental studies according to fit, preload, and surface roughness. Furthermore, a digitized photogrammetric technique for recording implant positions in the edentulous jaw was experimentally tested and compared with two conventional impression techniques. RESULTS: Laser-welded titanium frameworks had a lower success rate after 5 years in function than gold-alloy frameworks. The 5-year performance of CNC frameworks was similar to that of gold-alloy frameworks. The fit and precision of implant-supported CNC frameworks was significantly better compared with gold-alloy frameworks. Applications of veneering material did not significantly affect the fit of the titanium frameworks. The preload of CNC frameworks was similar to that of gold-alloy frameworks, both exhibiting significantly decreased preloads after repeated tightening. The preloads of titanium frameworks were similar before and after veneering. Unloaded milled titanium screw sites had significantly rougher surfaces than loaded sites, and loaded gold screws had rougher surfaces than unloaded. No correlation between surface of the screw joints and preload of veneered titanium frameworks was observed. The precision of photogrammetric impressions was comparable to that of conventional impression techniques. CONCLUSIONS: Implant-supported CNC-milled titanium frameworks are a viable alternative to gold-alloy castings in the edentulous jaw, and because a digital platform is used to manufacture these titanium frameworks, photogrammetric impressions can be made.

Adult↗
PubMed2005

[Comparative results of type II ossiculoplasty: incus transposition versus titanium PORP (Kurz)].

OBJECTIVE: The goal of this study was to compare the anatomical and functional results of two groups of patients having an ossiculoplasty type II, either with the incus, or with a PORP Bell Vario prosthesis (Kurz). MATERIALS AND METHODS: Retrospective study concerning 98 patients having had an ossiculoplasty type II with the incus (Incus group) and 50 patients having received a PORP titanium prosthesis Bell Vario from Kurz (Titanium group). RESULTS: The rate of extrusion was small (1% Incus group and 4% Titanium group). Average preoperative air bone gap of patients who received the Titanium prosthesis was 21.2 dB and 42.8 dB for the incus group. The average postoperative air bone gap was 16.9 dB Titanium group and 25.5 dB Incus group (p < 0.05). The gain was 18.7dB in the Incus group and 4.3 dB in Titanium group (p < 0.05). The difference between pre and post air conduction thresholds in both groups was statistically significant (p < 0.05). The post-op airbone gap was less on 20 dB in 62% of cases (Incus group) and 61% (Titanium group). There was no significant loss of the bone conduction thresholds in each group. CONCLUSION: Audiometric results obtained among patients with an incus transposition are better than those obtained with a PORP Titanium prosthesis. These results are to be appreciated by taking account of the greatest proportion of cholesteatoma and of reoperation in the Titanium group. The PORP titanium Bell Vario prosthesis (Kurz) is a material well tolerated by the middle ear as shown by the low rate extrusion. Its qualities (easy and precise measurement, easy positioning) make a material of choice of it when the patient's incus is not usable.

Adolescent↗