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PubMed2002

The effect of cage stiffness on the rate of lumbar interbody fusion: an in vivo model using poly(l-lactic Acid) and titanium cages.

STUDY DESIGN: A goat interbody fusion model using poly-(L-lactic acid) and titanium cages was designed to evaluate the effect of cage stiffness on lumbar interbody fusion. OBJECTIVE: To investigate the effect of cage stiffness on the rate of interbody fusion. SUMMARY OF BACKGROUND DATA: Various types of cages considerably exceed the stiffness of vertebral bone, which ultimately may lead to postoperative complications. To avoid these complications, poly-(L-lactic acid) cages with limited stiffness have been designed. The mechanical integrity of the cages remains intact for at least 6 months. METHODS: Interbody fusions were performed at L3-L4 of 15 Dutch milk goats, and one of three cages was randomly implanted: 1) a titanium cage (n = 3), 2) a stiff poly-(L-lactic acid) cage (n = 6), or 3) a flexible poly-(L-lactic acid) cage (n = 6). Interbody fusion was assessed radiographically by three independent observers 3 and 6 months after surgery. RESULTS: At 3 months, all the poly-(L-lactic acid) specimens showed ingrowth of new bone, but with radiolucency in the fusion mass. At 6 months, solid arthrodesis was observed in four of six poly-(L-lactic acid) specimens, advanced ingrowth in one specimen, and infection in one specimen. Titanium cages showed ingrowth of bone, but with radiolucency in the fusion mass. Interbody fusion using poly-(L-lactic acid) cages showed a significantly higher rate statistically (P = 0.016) and more complete fusion than titanium cages of the same design. CONCLUSIONS: The reduced stiffness of poly-(L-lactic acid) cages showed enhanced interbody fusion, as compared with titanium cages after 6 months. Bioabsorbable poly-(L-lactic acid) cages thus may be a viable alternative to current interbody cage devices, thereby avoiding the concomitant problems related to their excessive stiffness. However, the bioabsorbability of the poly-(L-lactic acid) cages awaits investigation in a long-term study currently underway.

Absorbable Implants↗

PubMed2002

Better treatment of vertebral osteomyelitis using posterior stabilization and titanium mesh cages.

There is no scientific consensus on the role of posterior instrumentation in vertebral osteomyelitis. No study has examined the use of titanium cages to reconstruct the anterior column of the spine with vertebral osteomyelitis. Here the authors evaluated the efficacy of using titanium mesh cages anteriorly and posterior instrumentation after anterior debridement in the surgical treatment of vertebral osteomyelitis. In one center, 21 consecutive patients had surgery for vertebral osteomyelitis. The mean follow-up time was 67 months (range, 24 to 120 months). Ten patients received supplemental posterior instrumentation. Five patients had reconstruction of the anterior column with titanium cages. Greater improvement in sagittal alignment was noted for patients with cages implanted (p = 0.0009) and for those with posterior instrumentation (p = 0.005). Patients who received cages had greater (p = 0.0006) correction of their coronal alignment than did those patients without cages. A trend toward fewer postoperative complications emerged for patients who had posterior stabilization or titanium cages. These results support the use of posterior stabilization and titanium cages in the surgical treatment of vertebral osteomyelitis.

Adult↗

PubMed2007

Titanium versus stainless steel for anterior spinal fusions: an analysis of rod stress as a predictor of rod breakage during physiologic loading in a bovine model.

STUDY DESIGN: In vitro biomechanical evaluation of rod stress during physiologic loading of anterior scoliosis instrumentation. OBJECTIVES: To determine effects of material properties and rod diameter on rod stresses in anterior scoliosis instrumentation. SUMMARY OF BACKGROUND DATA: Relationships between instrumentation dimensions, materials, and potential rod failure in anterior scoliosis instrumentation remain unclear. METHODS: Eighteen immature bovine spines were randomized to 3 groups: 1) 4.0-mm stainless steel, 2) 5.0-mm stainless steel, and 3) 4.75-mm titanium alloy. Spines underwent physiologic tests in flexion-extension, lateral bending, and torsion. Rod surface strains were converted to rod stress and normalized to each material's yield stress. Construct stiffness and the normalized rod stresses were compared with a one-way ANOVA (P < 0.05). RESULTS: The 4.0-mm steel and 4.75-mm titanium construct stiffness was similar across all tests. The 5.0-mm steel system was significantly stiffer than 4.0-mm steel (lateral bending/torsion) and 4.75-mm titanium (torsion/flexion) constructs. Rod surface stress was significantly lower for the 4.75-mm titanium rod compared with 4.0-mm and 5.0-mm steel rods for all tests. CONCLUSIONS: The percentage of yield stress was lowest for the 4.75-mm Ti rod for all tests due to titanium's greater yield stress. This suggests the 4.75-mm rod has a lower fatigue failure risk than either steel construct.

Animals↗

PubMed2006

Single-stage treatment of pyogenic spinal infection with titanium mesh cages.

STUDY DESIGN: Single institution retrospective review. OBJECTIVES: To report a series of pyogenic spinal infections treated with single-stage debridement and reconstruction with titanium mesh cages. SUMMARY OF BACKGROUND DATA: Various studies have reported surgical results of pyogenic spinal osteomyelitis with anterior debridement, strut grafting and fusion, including delayed posterior spinal instrumentation. Additionally, various authors have recommended against the use of instrumentation because of the concern about glycocalyx formation on the metal and chronic infection. At our institution, we routinely treat chronic vertebral osteomyelitis with single-stage debridement, reconstruction with a titanium mesh cage filled with allograft chips and demineralized bone matrix, and posterior pedicle screw instrumentation. To our knowledge, this is the largest single series reporting single-stage debridement and instrumentation of pyogenic spinal infection with titanium mesh cages and posterior instrumentation. MATERIALS AND METHODS: We retrospectively reviewed the patient records and radiographs of 21 consecutive patients (average age 49.3 years, range 23 to 80 years) with pyogenic vertebral osteomyelitis, all treated with titanium mesh cages. Average follow-up was 44 months (range, 25 to 70 months). Spinal levels included 6 thoracic, 4 thoracolumbar, 9 lumbar, and 2 lumbosacral (L5-S1) lesions. All patients had preoperative serum evaluation, which usually included blood cultures, complete blood count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), in addition to plain radiographs and magnetic resonance imaging. A positive needle biopsy was available in only 2/7 patients (29%), and overall, preoperative pathogen identification was available in only 7/21 patients (33%). All patients were treated postoperatively with a minimum of 6 weeks of intravenous antibiotics, with a specific antibiotic regimen directed toward the postoperative pathogen when identified (17/21 cases). Extensive radiographic evaluation was also performed. RESULTS: ESR and CRP were routinely elevated (18/20 and 11/17 cases respectively), whereas the white blood count was elevated in only 8 out of 21 cases (38%). The average duration of symptoms to diagnosis was approximately 13.6 weeks (range 3 weeks to 10 months). The indications for surgery included neurologic compromise, significant vertebral body destruction with loss of sagittal alignment, failure of medical treatment, and/or epidural abscess. All patients had resolution of infection, as noted by normalization of the ESR and CRP. Further, 16 out of 21 patients also had a significant reduction of pain. There were no deaths or new postoperative neurologic compromise. The most common pathogen was Staphylococcus aureus. Two patients required a second surgery (posterior irrigation and debridement) during the same admission for persistent wound drainage. Radiographically, the average segmental kyphosis (or loss of lordosis) was 11.5 degrees (range, 0 to 24 degrees) preoperatively, and +0.8 degrees (range, -3 to +5 degrees) at latest postoperative follow-up. There was an average of 2.2 mm cage settling (range, 0 to 5 mm) on latest follow-up. There were no instrumentation failures, signs of chronic infection, or rejection. CONCLUSIONS: Titanium mesh cages present a viable option for single-stage anterior surgical debridement and reconstruction of vertebral osteomyelitis, without evidence of chronic infection or rejection. When used in conjunction with pedicle screw instrumentation, there is minimal cage settling without loss of sagittal alignment.

Adult↗

PubMed2005

Bacterial adherence to titanium surface coated with human serum albumin.

HYPOTHESIS: An albumin coating on titanium implants will inhibit bacterial adhesion on the implant surface. BACKGROUND: Bacterial, protein, and platelet adhesion on otologic implants and tympanostomy tubes is a major reason for implant sequelae and can eventually lead to implant removal. The role of albumin coating of the implant in prevention of protein adhesion on implant surface has already been tested by the authors. In the present study the authors examined the in vitro adherence of Staphylococcus aureus and Pseudomonas aeruginosa on an albumin-coated and uncoated titanium surface. METHODS: Human serum albumin (HSA)-coated and uncoated titanium surfaces were exposed to viable S. aureus and P. aeruginosa and, after washings, photographed by fluorescence microscopy to quantify the adhered bacteria, which was stained with acridine orange. RESULTS: Bacteria in the suspension adhered at a significantly lesser rate to the coated surfaces than to the uncoated surfaces, with overall bacterial adhesion dependent on bacterial concentration. Binding of S. aureus on HSA-coated surfaces was inhibited significantly (from 82 to 95% depending on concentration). Binding of P. aeruginosa was inhibited from 29 to 37%. CONCLUSION: Because albumin coating can reduce bacterial adherence on titanium surfaces in vitro, reduction is possible in bacterial contamination and infection of the HSA-coated titanium implant in vivo.

Bacterial Adhesion↗

PubMed2005

Study of osteointegration of a titanium prosthesis to the stapes: observations on an accidentally extracted stapes.

BACKGROUND: Titanium is a well-established implant material, and its use in ossicular chain reconstruction during middle ear surgery is increasing. HYPOTHESIS: Bony fixation of titanium prostheses has to be considered using this material. Contact with bony structures of the middle ear may result in immobilization. In revision procedures, there is a potential risk of damaging or extracting adherent structures such as the stapes. METHODS: This is a case report of an accidentally extracted stapes resulting from bony fixation of a titanium prosthesis in revision tympanoplasty. The surgical specimen was examined by microscopy, histology, and scanning electron microscopy. Energy dispersive x-ray analysis was used to confirm the elemental composition of the extracted stapes and the titanium prosthesis. RESULTS: The prosthesis showed good biocompatibility at the implantation site, with signs of bone resorption of the stapes suprastructure. However, bony fixation of the undersurface of the prosthesis foot to the stapes footplate was confirmed by ultrastructural analysis. CONCLUSION: In revision tympanoplasty, bony fixation of the titanium prosthesis should be considered.

Audiometry, Pure-Tone↗

PubMed2005

Comparison of titanium and Robinson stainless steel stapes piston prostheses.

OBJECTIVE: Although stainless steel stapes prostheses have generally been considered magnetic resonance imaging safe, there is concern that this may change with the development of more powerful imaging systems. The objective of the study was to determine whether a titanium piston stapes prosthesis would be audiometrically and surgically equivalent to a Robinson stainless steel piston for stapedectomy. STUDY DESIGN: Retrospective chart review. SETTING: Private otology practice. PATIENTS: In all, 50 patients underwent stapedectomy with a Gyrus titanium piston prosthesis. These patients were matched on the basis of age and preoperative bone-conduction scores with patients who underwent stapedectomy with a Robinson stainless steel piston prosthesis. MAIN OUTCOME MEASURES: Audiometric results are analyzed, and surgical complications noted. RESULTS: There was no significant difference between groups in hearing improvement or postoperative air-bone gap. The mean four-frequency hearing improvement was 27.7 dB for the stainless steel group and 27.8 dB for the titanium group. The mean postoperative air-bone gap was 2.65 dB for the stainless steel group and 2.60 for the titanium group. Neither group had a surgical complication. CONCLUSION: The titanium stapes prosthesis is a good alternative to a stainless steel prosthesis.

Adult↗

PubMed2004

Reconstruction using a three-dimensional orbitozygomatic skeletal model of titanium mesh plate and soft-tissue free flap transfer following total maxillectomy.

The surgical strategy for maxillary reconstruction after maxillectomy has yet to be standardized. The authors developed a technique using a three-dimensional orbitozygomatic skeletal model of a titanium mesh for skeletal reconstruction after maxillectomy. From May of 1996 to September of 2000, 18 patients underwent reconstruction using the titanium mesh model in conjunction with a soft-tissue free flap following total maxillectomy for a maxillary malignancy. The soft-tissue free flap was conventional and consisted of two skin paddles to the maxillary defect. One skin paddle became the lateral nasal wall and the other was used to close the palatal defect. After modeling, the titanium mesh plate was implanted between the orbital contents and the upper edge of the free flap to lie over the front of the flap. The model was fixed to the residual zygoma laterally and to the nasal or frontal bone medially. The palatal skin paddle was anchored by three or four dermal stitches to the bottom edge of the titanium mesh to create a concave neopalate that allowed the patient to wear a denture. Thirteen of 18 patients who underwent implantation had good facial appearance and oral function. This procedure prevented lagophthalmos, facial deformity, and sagging of the palatal skin paddle caused by gravitational force. Five patients (27.8 percent) developed exposure or infection of the implant and lost the benefit of having the prosthesis. However, treatment did not require total removal of the implant. Maintaining adequate tissue volume during soft-tissue transfer on either side of the mesh plate may minimize the complication rate. Titanium mesh implantation for skeletal reconstruction after maxillectomy avoids the need for bone grafting and may be especially beneficial in fragile or aged patients.

Aged↗

PubMed2002

In vitro electrical properties for iridium oxide versus titanium nitride stimulating electrodes.

Stimulating electrode materials must be capable of supplying high-density electrical charge to effectively activate neural tissue. Platinum is the most commonly used material for neural stimulation. Two other materials have been considered: iridium oxide and titanium nitride. This study directly compared the electrical characteristics of iridium oxide and titanium nitride by fabricating silicon substrate probes that differed only in the material used to form the electrode. Electrochemical measurements indicated that iridium oxide had lower impedance and a higher charge storage capacity than titanium nitride, suggesting better performance as a stimulating electrode. Direct measurement of the electrode potential in response to a biphasic current pulse confirmed that iridium oxide uses less voltage to transfer the same amount of charge, therefore using less power. The charge injection limit for titanium nitride was 0.87 mC/cm2, contradicting other reports estimating that titanium nitride was capable of injecting 22 mC/cm2. Iridium oxide charge storage was 4 mC/cm2, which is comparable to other published values for iridium oxide. Electrode efficiency will lead to an overall more efficient and effective device.

Coated Materials, Biocompatible↗

PubMed2005

Effect of cryogenic treatment on nickel-titanium endodontic instruments.

AIM: To investigate the effects of cryogenic treatment on nickel-titanium endodontic instruments. The null hypothesis was that cryogenic treatment would result in no changes in composition, microhardness or cutting efficiency of nickel-titanium instruments. METHODOLOGY: Microhardness was measured on 30 nickel-titanium K-files (ISO size 25) using a Vicker's indenter. Elemental composition was measured on two instruments using X-ray spectroscopy. A nickel-titanium bulk specimen was analysed for crystalline phase composition using X-ray diffraction. Half of the specimens to be used for each analysis were subjected to a cryogenic treatment in liquid nitrogen (-196 degrees C) for either 3 s (microhardness specimens) or 10 min (other specimens). Cutting efficiency was assessed by recording operator choice using 80 nickel-titanium rotary instruments (ProFile 20, .06) half of which had been cryogenically treated and had been distributed amongst 14 clinicians. After conditioning by preparing four corresponding canals, each pair of instruments were evaluated for cutting efficiency by a clinician during preparation of one canal system in vitro. A Student's t-test was used to analyse the microhardness data, and a binomial test was used to analyse the observer choice data. Composition data were analysed qualitatively. RESULTS: Cryogenically treated specimens had a significantly higher microhardness than the controls (P < 0.001; beta > 0.999). Observers showed a preference for cryogenically treated instruments (61%), but this was not significant (P = 0.21). Both treated and control specimens were composed of 56% Ni, 44% Ti, 0% N (by weight) with a majority in the austenite phase. CONCLUSIONS: Cryogenic treatment resulted in increased microhardness, but this increase was not detected clinically. There was no measurable change in elemental or crystalline phase composition.

Cold Temperature↗

PubMedDate not supplied

A 4-year prospective study to assess peri-implant hard and soft tissues adjacent to titanium versus gold-alloy abutments in cemented single implant crowns.

PURPOSE: The purpose of this prospective clinical study was to compare titanium and gold-alloy abutments when used with cemented, implant-supported single-tooth crowns. For 4 years following prosthodontic rehabilitation, these abutments were evaluated with respect to peri-implant marginal bone levels and peri-implant soft tissue parameters. MATERIALS AND METHODS: During the years 1998 to 2000, 20 patients were selected from a patient population receiving treatment in the Implantology Department at the University of Padova, Italy. They all presented with single-tooth bilateral edentulous sites in the premolar/molar region with adequate bone width, similar bone height on each side, and an occlusal scheme that allowed for the establishment of identical occlusal cusp/fossa contacts on each side. Each subject received two identical implants (one in each edentulous site). One was randomly selected to be restored with a titanium abutment and a cemented implant-supported single-tooth crown, and the other was restored with a gold-alloy abutment and a cemented implant-supported single tooth crown. Data on peri-implant marginal bone levels and soft tissue parameters were collected for 4 years after abutment and crown insertion placement and analyzed to determine whether there was a significant (p< .001) difference with respect to the type of abutments (titanium vs. gold alloy) used. RESULTS: All subjects completed the study. All 40 implants survived, resulting in a cumulative implant success rate of 100%. Statistical analysis revealed no significant differences between the two groups with respect to peri-implant marginal bone levels and soft tissue parameters. CONCLUSIONS: Within the limitations of this study, the results indicate that there was no evidence of different response with the peri-implant marginal bone and soft tissue when titanium or gold-alloy abutments were used in conjunction with the cemented, single-tooth implant restorations provided for this limited patient population. There was no evidence of different behavior of peri-implant marginal bone and of peri-implant soft tissue when titanium abutments or gold-alloy abutments were used for cemented single-tooth implant restorations in this limited patient population.

Bone Resorption↗

PubMed2005

Laser therapy accelerates initial attachment and subsequent behaviour of human oral fibroblasts cultured on titanium implant material. A scanning electron microscope and histomorphometric analysis.

The aim of the study was to investigate the effect of low-level laser therapy (LLLT) on attachment and proliferation of human gingival fibroblasts (HGF) cultured on titanium implant material. HGF were exposed to gallium-aluminum-arsenide diode laser at dosages of 1.5 or 3 J/cm(2) and then cultured on commercially pure titanium discs. Cell profile areas were measured after 1, 3 and 24 h, using scanning electron microscopy and an automatic image analyzer. The results were expressed as percentage of attachment. In order to investigate the effect of LLLT on cellular growth after 8 and 10 days, HGF were cultured on titanium discs for 24 h and then exposed to laser irradiation on 3 consecutive days. Colony-forming efficiency (CFE) and clonal growth rates (CGR) were measured. Cell viability was determined by Hoechst and prodidium iodide staining. Non-lased cultures served as controls. Morphologically, the cells spread well on all titanium surfaces, indicating good attachment by both irradiated and non-irradiated cells. Fibroblasts exposed to laser irradiation had significantly higher percentages of cell attachment than the non-exposed cells (P<0.05). CFE and CGR were also enhanced for the irradiated cells (P<0.05). Cell viability was high (>90%) in the irradiated and control groups, without significant differences. It is concluded that in vitro LLLT enhances the attachment and proliferation of HGF on titanium implant material.

Cell Adhesion↗

PubMed2005

Effect of magnetic field on the fibronectin adsorption, cell attachment and proliferation on titanium surface.

OBJECTIVES: We studied the effect of various static magnetic fields (SMFs) on the adsorption of specific recombinant fibronectin (FN) peptide (hFNIII9-10) on the titanium surface. Furthermore, the responses of human osteosarcoma TE-85 cells in the SMF were observed. MATERIAL AND METHODS: Various magnetic fields--1, 2, 3, 5, 7, 10 mT--were established by controlling the distance from Nd-Fe-B magnet to the disks. For FN adsorption experiment, machined titanium disks were incubated in 1 microM hFNIII9-10 at 37 degrees C overnight under magnetic field. The adsorbed hFNIII9-10 was measured as optical density (OD). For attachment study, TE-85 cells were incubated for 2 h on the hFNIII9-10 coated machined titanium disks and OD values were measured. As for proliferation study, titanium disks were incubated for 48 h after washing unattached cells in 2 h. The amount of proliferated TE-85 cell was also measured as OD value. Attachments of TE-85 cells under various intensities of magnetic field were observed using a scanning electron microscope. RESULTS: The amount of adsorbed hFNIII9-10 showed no significant difference between control (0 mT) and six experimental groups (1, 2, 3, 5, 7, 10 mT). However, TE-85 cells attached significantly higher in groups of 1, 2, 5, 10 mT than in control group (P=0). Cell attachment in groups of 3, 7 mT showed no significant difference with that of control group. TE-85 cells were observed to attach through filopodia. Especially in 1 mT, flattened cells were predominant. In proliferation assay, 1 mT stimulated TE-85 cells showed significantly higher proliferation than those in 2, 3 and 7 mT (P=0). CONCLUSION: Magnetic fields under 10 mT did not influence FN adsorption on the titanium surface. However, a significant effect was found on cell attachment and proliferation.

Adsorption↗

PubMed2005

Histomorphometry and micro-computed tomography of bone augmentation under a titanium membrane.

OBJECTIVES: Bone augmentation underneath an occlusive titanium membrane is evaluated in most cases by means of serial histological sections and histomorphometry. Micro-computed tomography (micro-CT) is a less invasive and dynamic technique to measure bone volume in animals of a size that fits into the gantry. The aim of the present study was to evaluate whether the latter approach could match histomorphometry to assess bone augmentation under a titanium membrane. MATERIAL AND METHODS: Pre-formed titanium cups were placed on the skull of 16 rabbits. Bone formation underneath the cups was allowed to occur for 12 weeks. The amount of bone volume assessed by micro-CT was expressed as a numerical unit. One unit volume corresponds to 0.043 mm3. The measurements reveal the volume of bone-like tissue under the membrane, with the same density as that of the original rabbit skull bone. Histological sections were cut along the same plane as the one used for the micro-CT images. The total bone surface was assessed by a digital image system in double-stained undecalcified histological sections and related to the maximum available surface of the titanium cups, which was on average 1366 mm2. RESULTS: The amount of total bone surface found under the titanium membrane varied between 40 and 163 mm2. Measured by micro-CT, the bone detected ranged from 3.7 to 396 numerical units. A highly significant (P<0.001) correlation was found between the total bone volume measured in conventional serial histological sections and by the micro-CT technique (r2=0.72). CONCLUSIONS: The total bone volume measured underneath a membrane using the micro-CT when compared with histological sections remained within a 16% error. This is because of the scattering effect of the metallic membrane and the impossibility to distinguish newly formed bone from the original skull bone on the micro-CT images.

Animals↗

PubMed2006

Titanium surface modification and its effect on the adherence of Porphyromonas gingivalis: an in vitro study.

AIM: Titanium dental implants are an important treatment option in the replacement of missing teeth. Implant failures can, however, occur and may be promoted by the loss of tissue as a result of local bacterial infection (peri-implantitis). OBJECTIVES: Bacterial adherence to implant surfaces is believed to be influenced by material surface roughness and surface-free energy parameters. Consequently, the aim of this study was to modify these properties of titanium and identify what effect these modifications had on subsequent bacterial adherence. MATERIALS AND METHODS: In this study, 16 titanium samples of different roughness (R(a) 34.57-449.42 nm) were prepared using specific polishing procedures. A further six samples were chemically altered by argon plasma discharge treatment and immersion in silane solutions to produce different surface hydrophobicities. An in vitro adhesion assay using Porphyromonas gingivalis was used to assess the effect of modification on bacterial adherence. RESULTS: A significant reduction in adhesion to materials categorised as being 'very smooth' (R(a) 34.57+/-5.79 nm) was evident. This reduction did not occur with 'smooth' (R(a) 155.00+/-33.36 nm), 'rough' (R(a) 223.24+/-9.86 nm) or 'very rough' (R(a) 449.42+/-32.97 nm) surfaces. Changing material surface hydrophobicity was also not found to effect bacterial adhesion. CONCLUSIONS: Adhesion of P. gingivalis to titanium was inhibited at surface roughness levels below those generally encountered for implant collars/abutments (R(a) 350 nm). Considerations of these findings may be beneficial in the production of titanium implants in order to reduce bacterial colonisation.

Bacterial Adhesion↗

PubMed1982

Corrosion of gold alloys and titanium in artificial saliva.

Two types of gold alloys and one type of pure titanium have been submitted to corrosion in artificial saliva for periods of up to about 2 months. The release of copper, gold or silver from the gold alloys as well as titanium from the titanium matrix was measured with nuclear tracer technique. The physical/chemical state of the corrosion products of gold alloys referring to the ionic state or presence in particulate form has been examined retaining the particulate matter on a glass filter. Copper was observed to be mainly present in the ionic state. Considerable amounts of gold were observed to be retained on the glass filter explained by the presence of gold in particular form or as a component of a dispersed colloidal phase. The estimation of the release of titanium was registered by the tracer nuclide 46Sc assuming particulate matter to be deteriorated from the titanium surface.

Chemical Phenomena↗

PubMed1996

Three-point bending strength of ceramics fused to cast titanium.

Titanium requires special ceramic systems for veneering. This study compared the three-point bending strength of three commercially available titanium ceramic systems with a NiCr-alloy with conventional ceramics. Three-point bend specimens 25 x 5 x 0.5 mm were cast from polyethylene patterns. After alpha-case removal, they were veneered with 8 x 5 x 1 mm of ceramics at the center of the bar. Specimens were tested in a universal testing machine without ageing, after thermocycling, and after 90 d storage in an electrolyte solution. Titanium-ceramic systems were found to have a significantly lower bond strength in comparison to the NiCr-ceramic system. One of the titanium ceramic systems had a significantly lower bond strength in comparison to the other systems investigated. It could be concluded that bonding between titanium and ceramics is obtainable; however, the achievable bonds strengths did not match the NiCr-ceramic control.

Analysis of Variance↗

PubMed1999

Bone-tissue formation and integration of titanium implants: an evaluation with newly developed enzyme and immunohistochemical techniques.

BACKGROUND: Examination of the tissue surrounding retrieved implants involve routine investigations on cut and ground sections. Undecalcified sections with implants in situ are histologically stained followed by qualitative and quantitative observations of the tissue response to the implants by light microscopy. PURPOSE: A novel technique that allows for the accurate definition and quantification of enzymes involved in bone formation (alkaline phosphatase) and resorption (acid phosphatase) in the tissue is presented. MATERIALS AND METHODS: Commercially pure titanium and titanium alloy (Ti6Al4V) implants were retrieved after 6 and 12 weeks of healing in rabbit bone. In addition, 4-week specimens from commercially pure titanium bone harvest chambers placed in rabbit bone were used. Undecalcified cut and ground sections were produced and evaluated with enzyme and immunohistochemical staining techniques. RESULTS: The titanium implants retrieved after 6 weeks of insertion in rabbit bone revealed a higher activity of both alkaline phosphatase and acid phosphatase activity compared to the implants followed for 12 months. The former samples revealed ongoing bone-tissue remodeling in the interface, whereas the latter ones showed steady-state bone conditions. Applying the new technique allowed for investigation of various bone proteins present in the tissue that had formed inside titanium canals of harvest chambers at various times of follow-up. CONCLUSIONS: The combination of routine histologic stainings with enzyme and immunohistochemical technique of cut and ground specimens is a valuable tool in the investigations of retrieved implants from humans and animals. This novel technique now may be used to describe the state of bone regeneration in the interface zone associated with implant research.

Acid Phosphatase↗