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PubMedDate not supplied

Three-dimensional bone response to commercially pure titanium, hydroxyapatite, and calcium-ion-mixing titanium in rabbits.

Three-dimensional bone response to 3 biomaterials--commercially pure titanium (Ti), hydroxyapatite (HA), and calcium-ion-mixing titanium (Ca-Ti)--embedded in the tibiae of rabbits was examined chronologically. The rabbits were sacrificed at 2, 4, and 8 weeks after implantation, and the percent bone volume around each implant was calculated from the implant surface to each of 4 measurements: 36 microns, 0.25 mm, 0.5 mm, and 1.0 mm in 2 regions (cortical bone and bone marrow regions). Percent bone volume in the cortical bone was consistent, whereas in the bone marrow region, the percent bone volume varied according to implant material, implantation period, and distance from the implant surface. With Ti implants the percent increased gradually up to 8 weeks at each distance, whereas in HA and Ca-Ti implants the percent was largest at 4 weeks and increased closer to the surface. The percent with Ti implants was largest at 36 microns to 0.25 mm. Aspect of bone response to Ca-Ti was its position intermediate between those of HA and Ti. The decrease of the percent at 8 weeks was smaller than HA.

Analysis of Variance↗
PubMed2000

[Effect of titanium substructure on color of porcelain-fused-to-titanium restoration].

OBJECTIVE: To study the effect of titanium substructure on color of porcelain-fused-to-metal restoration. METHODS: Standard samples of Dentsply DETREY-Carat and Tibond porcelain fused-to-metal restorations were made. Color Parameters were tested by cs-5 spectrophotometer. Statistic analysis was done and the color differences were calculated. RESULTS: Most of color parameters were found to be statistically significant at the P < or = 0.05 level at substructure layer. But no statistical significance existed after putting opaque and dentin porcelain. The values of color difference between two groups at opaque and dentin porcelain layers were all smaller than 1.5. CONCLUSIONS: Titanium substructure had no visually apparent effect on final color of porcelain-fused-to-metal restoration. There was no perceived color difference between corresponding shade of two Dentsply porcelain systems (DETREY-Carat and Tibond).

Color↗
PubMed2007

Marginal and internal adaptation of commercially pure titanium and titanium-aluminum-vanadium alloy cast restorations.

AIM: The purpose of this in vitro study was to investigate the marginal accuracy and internal fit of complete cast crowns and three-unit fixed partial dentures (FPDs) cast with commercially pure titanium (CPTi) and Titanium-Aluminum-Vanadium alloy (Ti-6Al-4V). METHODS AND MATERIALS: CPTi and Ti-6Al-4V alloy were used to cast twelve single crowns and twelve three-unit FPDs. A traveling microscope was used to measure marginal gap and discrepancies in internal fit. Two and one-way analysis of variance (ANOVA) analyses were used to determine the effects of the marginal and internal fit discrepancies. RESULTS: The Ti-6Al-4V alloy demonstrated a significantly smaller marginal gap than CPTi (P<0.0001). The recorded marginal discrepancies for both metals were within a clinically accepted range (<100 microm). The single crown fit discrepancy was significantly smaller than the three-unit FPD for both the CPTi and the Ti-6Al-4V alloy (P<0.0001). For the internal fit discrepancy, the occlusal surface showed the greatest gaps. CONCLUSIONS: The Ti-6Al-4V alloy demonstrated a better fit than CPTi. Single crowns showed an improved fit when compared with the three-unit FPD. Mid-occlusal internal gap demonstrated greater values than the axial internal gap. CLINICAL IMPLICATIONS: This in vitro study suggested marginal fit of complete crowns and three-unit FPDs cast by CPTi or Ti-6Al-4V alloy were within the range of what is clinically acceptable for longevity of restorations.

Alloys↗
PubMed1990

A study of the method of making dental prosthetic appliances by sintered titanium alloys: effect of copper powder content on properties of sintered titanium alloy.

The effects of added copper powder to the properties of the sintered titanium alloys were investigated by measuring the compressive strength and densities of the green and sintered compacts, the thermal expansion curves and dimensional changes in the sintered compacts, and the accuracy of the crown-type restorations. The compressive strengths of green compacts ranged from 55 to 75 MPa. The expansion of green compacts increased with increased copper content. The sintered density was lower than the green density. The compressive yield strength of sintered compacts ranged from 260 MPa to 410 MPa. The sintered compacts expanded from 0.35% to 1.03% and the expansion increased with increased copper content. The dimensional accuracy of crown-type restorations showed the same dimensional change tendencies as did the sintered compacts. These results showed that the fit and the strength of sintered titanium alloy restorations could be improved.

Copper↗
PubMed1988

Differences between the bony interfaces of titanium and hydroxyapatite-alumina plasma-sprayed titanium blade implants.

Histopathologic study was done to reveal the difference of bony interface in the mandibular bone between titanium blade implants and titanium implants coated with the mixture of hydroxyapatite-alumina by the plasma-spray technique, using the improved undecalcified histologic technique and the image analyzing system. In 4 adult shepherd dogs, the implantation was performed in the molar region of the mandible 2 months after tooth extraction. The coated implants and the non-coated ones were inserted respectively in the mandibles. They were sacrificed on the 5th, 7th, 14th and 28th day postoperatively. In 5-day implant after insertion, granulation tissues or fibrous connective tissues were observed around both implants in bone tissues. In 7-day implant, osteoid tissues regenerated around the apex of both implants, but attached a little to them. In 14-day implant, osteoid tissues or woven bone regenerated around both implants and attached more to the coated implant (approximately 13.7%) than the non-coated one (approximately 6.0%). In 28-day implant, regenerative woven or lamellar bone attached much more to the coated implant (approximately 63.4%) than the non-coated one (approximately 8.8%). Bony interface increased remarkably in the coated implants, chronologically. The results showed that the plasma-sprayed hydroxyapatite-alumina coating was effective for the initial fixation of endosseous dental implants.

Aluminum Oxide↗
PubMed1993

Titanium and titanium alloys as dental materials.

Because of light weight, high strength to weight ratio, low modulus of elasticity, and excellent corrosion resistance, titanium and some of its alloys have been important materials for the aerospace industry since the 1950s. Now, with the additional advantages of excellent biocompatibility, good local spot weldability, and easy shaping and finishing by a number of mechanical and electrochemical processes, these materials are finding uses in dental applications, such as implants and restorative castings. Although more research is still needed in areas such as development of optimal casting investments, porcelain veneering systems, device designs, and controlled biological responses, the present and future uses of titanium appear bright for dentistry.

Biocompatible Materials↗
PubMed1997

Titanium-porcelain system. Part II: Bond strength of fired porcelain on nitrided pure titanium.

Commercially pure titanium (CPT) substrate was subjected to porcelain firing and bond strengths under three-point bending mode (span length: 15 mm; crosshead speed: 0.5 mm/min) were evaluated. Experimental variables included surface treatments of CPT and porcelain firing schedules. Variables for the surface treatments were (1) sandblasting, (2) mono- and triple-layered nitridation, and (3) mono-layered chrome-doped nitridation. Variables for the porcelain firing schedule included (4) bonding agent application, (5) bonding agent plus gold bonding agent application, and (6) Procera porcelain application. All together eleven sample groups were prepared with different combination of aforementioned experimental variables. Statistically all of them exhibited no significant differences. Hence, we employed two further criteria; (I) the minimum bond strength should exceed the maximum porcelain strength per se, and (II) the CPT substrate should not be heated close to the beta-transus temperature. After applying these criteria, it was concluded that mono-layered nitridation and mono-layered application of chrome-doped nitridation on both (with and without) sandblasted and non-sandblasted surfaces were the most promising conditions for a successful Titanium-Porcelain System.

Dental Porcelain↗
PubMed2003

Small cluster models of the surface electronic structure and bonding properties of titanium carbide, vanadium carbide, and titanium nitride.

Density functional theory (DFT) calculations on stoichiometric, high-symmetry clusters have been performed to model the (100) and (111) surface electronic structure and bonding properties of titanium carbide (TiC), vanadium carbide (VC), and titanium nitride (TiN). The interactions of ideal surface sites on these clusters with three adsorbates, carbon monoxide, ammonia, and the oxygen atom, have been pursued theoretically to compare with experimental studies. New experimental results using valence band photoemission of the interaction of O(2) with TiC and VC are presented, and comparisons to previously published experimental studies of CO and NH(3) chemistry are provided. In general, we find that the electronic structure of the bare clusters is entirely consistent with published valence band photoemission work and with straightforward molecular orbital theory. Specifically, V(9)C(9) and Ti(9)N(9) clusters used to model the nonpolar (100) surface possess nine electrons in virtually pure metal 3d orbitals, while Ti(9)C(9) has no occupation of similar orbitals. The covalent mixing of the valence bonding levels for both VC and TiC is very high, containing virtually 50% carbon and 50% metal character. As expected, the predicted mixing for the Ti(9)N(9) cluster is somewhat less. The Ti(8)C(8) and Ti(13)C(13) clusters used to model the TiC(111) surface accurately predict the presence of Ti 3d-based surface states in the region of the highest occupied levels. The bonding of the adsorbate species depends critically on the unique electronic structure features present in the three different materials. CO bonds more strongly with the V(9)C(9) and Ti(9)N(9) clusters than with Ti(9)C(9) as the added metal electron density enables an important pi-back-bonding interaction, as has been observed experimentally. NH(3) bonding with Ti(9)N(9) is predicted to be somewhat enhanced relative to VC and TiC due to greater Coulombic interactions on the nitride. Finally, the interaction with oxygen is predicted to be stronger with the carbon atom of Ti(9)C(9) and with the metal atom for both V(9)C(9) and Ti(9)N(9). In sum, these results are consistent with labeling TiC(100) as effectively having a d(0) electron configuration, while VC- and TiN(100) can be considered to be d(1) species to explain surface chemical properties.

Journal Article↗
PubMed2004

Synthesis of di-, tri- and penta-nuclear titanium(IV) species from reactions of titanium(IV) alkoxides with 2,2'-biphenol (H(2)L(1)) and 1,1'-binaphthol (H(2)L(2)); crystal structures of [Ti(3)(mu(2)-OPr(i))(2)(OPr(i))(8)L(1)], [Ti(3)(OPr(i))(6)L(1)(3)], [Ti(5)mu(3)-O)(2)(mu(2)-OR)(2)(OR)(6)L(1)(4)](R = OPr(i), OBu(n)) and [Ti(2)(OPr(i))(4)L(2)(2)].

Reaction of titanium(iv) alkoxides [Ti(OR)(4)](R = OPr(i), OBu(n)) with 2,2[prime or minute]-biphenol [C(12)H(8)(OH)(2), H(2)L(1)] affords two trinuclear species [Ti(3)(OPr(i))(10)L(1)] and [Ti(3)(OPr(i))(6)L(1)(3)] each possessing an open-chain V-shaped arrangement of three titanium atoms with the former having both bridging alkoxide and biphenylate groups and the latter having only biphenylate as bridging groups. Variations in reaction conditions yield the pentanuclear species [Ti(5)([micro sign](3)-O)(2)(OR)(8)L(1)(4)](R = OPr(i), OBu(n)) which have two central bridging oxygen atoms in the Ti(5) framework and bridging alkoxide and biphenylate groups. In contrast 1,1[prime or minute]-binaphthol [C(24)H(12)(OH)(2), H(2)L(2)] yields the dinuclear [Ti(2)(OPr(i))(4)L(2)(2)] where only the binaphthylate ligands act as bridging groups. Some of the compounds show catalytic activity in esterification reactions.

Journal Article↗
PubMed1991

Quantitative analysis of in vivo tissue responses to titanium-oxide- and hydroxyapatite-coated titanium alloy.

We have previously studied a large number of histological specimens of biomaterials and found that regions with and without an intervening fibrous membrane coexisted in many specimens. Therefore, it appears necessary to perform an evaluation of the entire specimen when histologically assessing the affinity of bone for a biomaterial. Accordingly, we performed a quantitative histological evaluation of hydroxyapatite (HAP)- and titanium-oxide(TiO2)-coated Ti-6A1-4V and uncoated Ti-6A1-4V (control) by determining the affinity index. This was defined as the length of bone directly opposed to the implant/the total length of the bone-implant interface X 100%. The test materials were inserted into the distal epiphyseal region of the femurs of adult dogs, and follow-up quantitative histological comparisons were performed from 4 weeks to 96 weeks. The HAP-coated implants had the highest affinity index 4 weeks after insertion, and this superiority was maintained up to 96 weeks. There was a significant difference in affinity index between HAP-coated implants and control implants (P less than 0.001), while TiO2-coated implants showed no significant difference in comparison to the control.

Alloys↗
PubMed2003

The role of titanium in the altered endotoxin-induced nitric oxide synthase expression in alveolar macrophages from titanium-alloy-implanted rats.

We have found that the concentration of titanium (Ti) in the blood of patients with loosened Ti-alloy prostheses is elevated. An increase in the levels of elemental Ti in the blood and lung tissues of rats with an alloyed-Ti implant also has been found. The cellular reaction to elevated elemental Ti in the circulation remains unclear. We further performed experiments to examine the changes of inducible nitric oxide synthase (iNOS) expression in alveolar macrophages from alloyed-Ti-implanted rats. The elevation of nitrite and iNOS expression induced by lipopolysaccharide (LPS) was suppressed. The in vitro effect of a soluble form of Ti was further investigated. Ti (0.01-0.06 mM) inhibited the LPS-induced nitrite production and iNOS expression in alveolar macrophages from normal rats without any cytotoxic effects. LPS induced protein tyrosine phosphorylation, tyrosine-phosphorylation of lyn (a CD14-receptor-associated-tyrosine kinase), and degradation of IkappaB-alpha protein (inhibitor of NF-kappaB) in alveolar macrophages. These events were inhibited by co-incubation with Ti. These results indicate that elemental Ti may impair iNOS expression in alveolar macrophages through the alteration of protein tyrosine phosphorylation and NF-kappaB activation. The inhibitory action of Ti on cellular responses of alveolar macrophages may be anti-inflammatory and thus may depress local defense mechanisms related to microbial killing.

Alloys↗
PubMed2003

In vitro osteoblast response to anodized titanium and anodized titanium followed by hydrothermal treatment.

In this study, Titanium (Ti) surfaces were modified using anodization. The electrolyte used for anodization was a mixture of calcium glycerophosphate and calcium acetate. The anodized surfaces were divided into three groups. Hydrothermal treatments were performed on two of the anodized groups for either 2 or 4 h. In vitro osteoblast response to anodized oxide and the hydrothermal treated oxide after anodization was evaluated in this study. Calcium and phosphorus ions were deposited on the Ti oxide during anodization. Anodized surfaces following a 4-h hydrothermal treatment were observed to promote the growth apatite-like crystals as compared with anodized surfaces after a 2-h hydrothermal treatment. Cellular function and onset of mineralization, as indicated by protein production and osteocalcin production, respectively, also were observed as enhanced on hydrothermal-treated surfaces. It was thus concluded from this study that calcium phosphate and apatite-like crystals could be deposited on Ti surfaces using anodization and a combination of anodization and hydrothermal treatment. It was also concluded that the phenotypic expression of osteoblast was enhanced by the presence of calcium phosphate or apatite-like crystals on anodized or hydrothermally treated Ti surfaces.

Alkaline Phosphatase↗
PubMedDate not supplied

Percutaneous vertebroplasty in a broken vertebral titanium implant (titanium mesh cage).

We report the case of a percutaneous consolidation of a broken vertebral implant (Surgical Titanium Mesh Implants; DePuy Spine, Raynham, MA, USA) by vertebroplasty. Four years after anterior spondylectomy with cage implantation and stabilization with posterior instrumentation, the patient was admitted for excruciating back pain. Radiographs showed fracture of the cage, screw, and rod. An anterior surgical approach was deemed difficult and a percutaneous injection of polymethyl methacrylate into the cage was performed following posterior instrumentation replacement. This seems to be an interesting alternative to the classical anterior surgical approach, which is often difficult in postoperative conditions.

Breast Neoplasms↗
PubMed2000

Titanium-alloy enhances bone-pedicle screw fixation: mechanical and histomorphometrical results of titanium-alloy versus stainless steel.

Several types of pedicle screw systems have been utilized to augment lumbar spine fusion. The majority of these systems are made of stainless steel (Ss), but titanium-alloy (Ti-alloy) devices have recently been available on the market. Ti-alloy implants have several potential advantages over Ss ones. High bioactivity and more flexibility may improve bone ingrowth and mechanical fixation, and the material also offers superior magnetic resonance imaging (MRI) and computed tomography (CT) resolution and significantly less signal interference. However, no data are available from loaded spinal constructs regarding bony ingrowth and mechanical fixation. The aim of this study was to analyse the effect of Ti-alloy versus Ss pedicle screws on mechanical fixation and bone ingrowth in a loaded mini-pig model. Eighteen adult mini-pigs underwent total laminectomy and posterolateral spinal fusion at L3-L4, and were randomly selected to receive either Ss (n = 9) or Ti (n = 9) pedicle screw devices. In both groups, the device used was compact Cotrel-Dubousset instrumentation (Sofamore Danek) of an identical size and shape. The postoperative observation time was 3 months. Screws from L3 were used for histomorphometric studies. Mechanical testing (torsional tests and pull-out tests) was performed on the screws from L4. The Ti screws had a higher maximum torque (P < 0.05) and angular stiffness (P < 0.07), measured by torsional testing. In the pull-out tests, no differences were found between the two groups with respect to the maximum load, stiffness and energy to failure. No correlation between removal torque and the pull-out strength was found (r = 0.1). Bone ongrowth on Ti was increased by 33% compared with Ss (P < 0.04), whereas no differences in bone volume around the screws were shown. Mechanical binding at the bone-screw interface was significantly greater for Ti pedicle screws than for Ss, which was explained by the fact that Ti screws had a superior bone ongrowth. There was no correlation between the screw removal torque and the pull-out strength, which indicates that the peripheral bone structure around the screw was unaffected by the choice of metal.

Animals↗
PubMed2005

Monocyte viability on titanium and copper coated titanium.

The role of apoptosis/cell death in the inflammatory response at the implanted materials is unexplored. Two surfaces with different cytotoxic potential and in vivo outcomes, titanium (Ti) and copper (Cu) were incubated in vitro with human monocytes and studied using a method to discriminate apoptotic and necrotic cells (Annexin V/PI staining). Further, staurosporine, a potent inducer of apoptosis, was added to the surface adherent monocytes. Lactate dehydrogenase (a marker of cell membrane injury) and TNF-alpha and IL-10, cytokines, previously suggested to play a major role in the monocyte apoptosis, were assayed in the culture medium. The results demonstrated that Ti surfaces displayed enhanced monocyte survival and production of IL-10 and TNF-alpha. Cu adherent cells exhibited apoptotic signs as early as 1h after incubation. In contrast to Ti, after 48 h the predominance of apoptotic cells switched to apoptotic/necrotic cells on Cu surfaces. Staurosporine treatment of Ti adherent cells mediated similar type of cell death. LDH and cytokine contents were low around Cu surfaces, partly explained by interference between Cu ions and LDH and cytokines. This study suggests that material properties rapidly influence the onset of human monocyte apoptosis and progression to late apoptosis/necrosis. Early detection of apoptosis and cell death may be important for the understanding of the biological response to implanted materials.

Annexin A5↗
PubMed2003

The significance of the surface properties of oxidized titanium to the bone response: special emphasis on potential biochemical bonding of oxidized titanium implant.

The aim of the present study is to investigate bone tissue reactions to various surface oxide properties, in particular to different surface oxide chemistry of oxidized titanium implants (grade 1). One control and three test screw-shaped implant groups were prepared. Controls were turned implants. Test implants, i.e. S implants, P implants and Ca implants were by the micro-arc oxidation (MAO) method. The surface characterizations were performed with X-ray photoelectron spectroscopy, Auger electron spectroscopy, scanning electron microscopy, X-ray diffractometry and TopScan 3D. Eighty implants were inserted in the femora and tibiae of ten mature New Zealand white rabbits for 6 weeks. The removal torque values (RTQ) showed significant differences between S implants and controls (p=0.022), Ca implants and controls (p=0.0001), Ca implants and P implants (p=0.005) but did not show significant differences between the others (p>0.05). In addition, the bone to metal contact (BMC) around the entire implants demonstrated 186% increase in S implants, 232% increase in P implants and 272% increase in Ca implants when compared to the paired control groups. Based on the comparative analysis of the surface characteristics resulting different bone responses between all groups, it was concluded that surface chemistry and topography separately or together play important roles in the bone response to the oxidized implants.

Animals↗
PubMed1999

A 5-year comparison of hydroxyapatite-coated titanium plasma-sprayed and titanium plasma-sprayed cylinder dental implants.

OBJECTIVE: A preliminary report from this study showed that hydroxyapatite-coated (HA) titanium plasma-sprayed (TPS) cylinder implants had fewer failures than TPS cylinder implants before prosthetic loading. The purpose of this article is to report the long-term success associated with the 2 systems. In addition, local and systemic factors that may influence the success or failure of the implants were analyzed. STUDY DESIGN: Each of 65 subjects was randomized to either HA-coated TPS or TPS cylinder implants. Loss of an implant was considered a failure. Failures were analyzed in terms of the coating of the implant, age and gender of the patient, location and length of the implant, opposing dentition, and smoking status. Data were statistically analyzed through use of chi-square tests. RESULTS: Of 351 implants that were placed, 13 were lost before prosthetic loading and 17 were lost after prosthetic loading. The overall success rate was 92.8%. Three hundred thirty-eight implants were prosthetically loaded. The implant success rate after prosthetic loading was 95.3%. There was an overall nonsignificant higher failure rate for the TPS implants (8.0%). Patient age and patient gender were nonsignificant variables. Ten-mm implants had a significantly higher failure rate (17.4%; chi-square, 1.00; P = .39). Before prosthetic loading, more implants failed in the posterior mandible; after prosthetic loading, more implants failed in the anterior maxilla (chi-square, 8.97; P = .03). More implants failed when they were opposed by natural dentition or hybrids (chi-square, 7.36; P = .007). Smoking history was a significant factor (chi-square, 5.2; P = .002). CONCLUSIONS: Statistically, there is little difference between the 2 systems. Local and systemic factors appear to play a greater role in implant failure than does the surface of the implant.

Adult↗
PubMed1998

Adhesion of periodontal bacteria to titanium, and titanium alloy powders.

In this study, the adhesion of radioactively labeled Actinomyces viscosus (A. viscosus), Actinobacillus actinomicetemcomitans (Aa) and Porphyromonas gingivalis (P. gingivalis) to titanium (Ti) and Ti-6-Al-4V alloy (Ti-alloy) coated with albumin or human saliva was investigated. All the tested bacteria displayed greater attachment to Ti-alloy than to Ti. P. gingivalis exhibited less adhesion to Ti and Ti-alloy than did the other bacterial strains. Adhesion of A. viscosus and Aa was greatly reduced when Ti or Ti-alloy were coated with albumin or saliva. P. gingivalis demonstrated a lesser reduction in adhesion to albumin or saliva-coated surfaces. The results show that oral bacteria have different adhesion affinities for Ti and Ti-alloy and that both albumin and human saliva reduce bacterial adhesion.

Actinomyces viscosus↗