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PubMed1997

Adsorption of chondroitin-4-sulphate and heparin onto titanium: effect of bovine serum albumin.

The adsorption of chondroitin-4-sulphate (C4S) and heparin onto titanium has been studied in the absence and presence of bovine serum albumin (BSA). Isotherm data (0.02 M calcium acetate, pH 6.8) have shown that BSA in solution and BSA-coated titanium result in decreased adsorption for both C4S and heparin. For the BSA in solution data, C4S/heparin and BSA may compete for the same sites on the titanium surface via calcium ions, or alternatively in the case of heparin, complexes of heparin and BSA form in solution, leading to less binding due to steric effects. Evidence of an interaction between heparin and BSA in solution has been shown in this study, there being negligible interaction between C4S and BSA. BSA adsorption from solution investigated in the presence of C4S/heparin decreases with increasing C4S/heparin solution concentration. This may be due to a glycosaminoglycan (GAG) induced conformational change of BSA from a compact to an extended structure. The decreased adsorption onto BSA-coated titanium may be due to masking of the GAG binding sites, this effect being greater for C4S. Desorption of BSA from the pre-coated titanium in the presence of C4S and heparin is <10% and <30% respectively, indicating that BSA is strongly bound to the titanium surface.

Adsorption↗

PubMed1999

The effect of hydroxyapatite coating on bony ingrowth into grooved titanium implants.

This study was undertaken to investigate the relative importance of a hydroxyapatite (HA) coating and the macrotexture of titanium implants to the quality of bony ingrowth and fixation. Various types of titanium cylinders were implanted into the cancellous bone of the intercondylar region of the distal femur of the dog. The animals were sacrificed at intervals post-implantation and the implants were evaluated histologically for amount of bony ingrowth and mechanically by the means of a push-out test. Our results demonstrated that when grooved titanium implants are used, the addition of HA coating significantly improved the biologic fixation. In addition, a groove depth of 1 mm was found to give significantly better fixation than 2 mm. When compared to implants with traditional, beads-coated porous surfaces, HA-coated grooved titanium implants were found to show better fixation at 4 weeks after implantation, but, significantly inferior fixation at 12 weeks after implantation. We concluded that while a groove depth of 1 mm was optimal in HA-coated, grooved titanium implants, they remain inferior to beads-coated titanium implants with respect to longer-term fixation. More research needs to be addressed at improving the macrotexture environment of grooved implants to enhance long-term bony ingrowth.

Animals↗

PubMed1998

Cytokeratin expression in human oral gingival epithelial cells: in vitro regulation by titanium-based implant materials.

To evaluate whether cytokeratin expression in human oral epithelial cells could be influenced by implant materials used in dental surgery, passaged human oral gingival epithelial cells were seeded on commercially pure titanium (CP-Ti) or on Ti6Al4V titanium alloy. Confluence was achieved after about 15 days on both substrates. Cells formed at that time, an organized layer of densely packed polygonal cells, and harbored a filamentous cytokeratin network typical of epithelial cells. Immunochemistry and immunoblot analysis were used to detect modifications of the amount of individual CK polypeptides (CK7, 8, 13, 18 and 19) in function of the culture substrate. Results showed that the level of CK8, CK18 and CK19 expression was not altered whatever the culture substrate used. The expression of CK13 was reduced in epithelial cells cultured on the titanium alloy, as compared with commercially pure titanium. Conversely, the level of CK7 was higher on the Ti6Al4V alloy than on commercially pure titanium. This study suggests that titanium-based implant materials could influence differently the phenotype of oral gingival epithelial cells.

Alloys↗

PubMed1998

Casted titanium for dental applications: an XPS and SEM study.

Casted titanium for dental crowns has been investigated by means of X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The samples were prepared according to the Ohara process. XRD analysis revealed that the investment consisted essentially of SiO2, Mg2P2O7, SiO2 x H2O and Mg2SiO4. SEM experiments combined with EDX analysis revealed the following atomic concentrations Si (62.6%), Mg (19.7%), P (17.1%), and Ca (0.6%). After casting, the titanium samples exhibit a rough and irregular surface, and XRD analysis indicated that titanium contains essentially the alpha phase and traces of the beta phase. After demoulding titanium samples, the investment side which was in contact with titanium was black colored, proving the reaction between titanium and the investment. XPS analysis performed on this side of the investment indicated that the Si 2p peak presents a shoulder on the low binding energy side and thus suggest that SiO2 has been transformed into metallic Si.

Chemical Phenomena↗

PubMed1999

Nanoindentation studies of titanium single crystals.

Titanium single crystal planes of different atomic density have been reported to show different oxidation characteristics. The differences in oxide characteristics have further been demonstrated to lead to differences in osteoblast attachment. Investigations of the preferred crystallographic planes of titanium for osteoblast attachment can be used to optimize the surfaces of single crystal and polycrystalline titanium implants for anchoring various prostheses. Nanoindentation techniques were used to determine mechanical properties of two crystallographic planes of titanium of different atomic density. Modulus of elasticity of 128 +/- 10 GPa was obtained for polycrystalline titanium and 123 +/- 5 and 124 +/- 6 GPa for the basal plane and pyramidal planes, respectively. The variation of modulus with crystal orientation was not greater than the statistical variation in the data. Surface hardness values were 2.1 +/- 0.1 GPa for the polycrystalline sample and 1.6 +/- 0.1 and 1.9 +/- 0.1 GPa, respectively, for the basal and pyramidal planes. Curves of hardness as a function of depth (0-2000 nm) obtained from electrochemically polished surfaces showed a sharp increase at shallow depths and may reflect changes caused by oxidation of the titanium surfaces.

Biocompatible Materials↗

PubMed1999

Comparison of the bond compatibility of titanium and an NiCr alloy to dental porcelain.

OBJECTIVES: The aim of this study was to investigate the bond compatibility between porcelain and titanium, by using three-point bending, oxide adherence and thermal expansion tests, and to compare the results with those of a conventional NiCr alloy-porcelain system. METHODS: The three-point bending test was used and the results were evaluated according to DIN draft 13927. Fractured surfaces of the metal and porcelain were examined macroscopically. The oxide adherence test was applied to titanium and NiCr alloy with appropriate oxidation degrees. After an oxide film was formed on the specimens, tensile strength test was applied. Oxide adherence strength values were set and fractured surfaces were examined macroscopically. In the thermal expansion test, thermal expansion curves and thermal expansion coefficients of titanium, NiCr alloy and tested porcelains were determined. Differences in thermal expansion values (delta alpha) in all metal-porcelain pairs were calculated to allow inferences to be made about residual stress levels. RESULTS: The bending strengths of all groups were found to be within the acceptable standard levels. At the end of the oxide adherence test, the results indicated that the adherence of the formed oxides to the metals were at a desired level. As a result of the thermal expansion test, the titanium-porcelain and NiCr-porcelain systems showed compressive thermal stress. However, the titanium-porcelain pair exhibited large positive delta alpha values. This results is found to be above the proposed thermal compatibility. CONCLUSIONS: It was concluded that the bond compatibility between titanium and porcelain was comparable with the NiCr-porcelain system.

Chromium Alloys↗

PubMed1993

Should titanium miniplates be removed after bone healing is complete?

A prospective study of 32 patients was performed to analyze black pigmentation in the soft tissue covering titanium miniplates. This soft tissue was compared with the soft tissue covering Champy stainless steel plates. All plates were removed 8 months after application. Macroscopically visible pigmentation was found in 25.6% of the soft tissue covering titanium miniplates and in none of the soft tissue covering Champy stainless steel plates. Microscopically visible pigmentation was found in 71.8% of the soft tissue covering titanium miniplates and in 65.3% of the soft tissue covering Champy stainless steel plates. Energy-dispersive x-ray analysis of the soft tissue covering titanium miniplates revealed only the presence of titanium dioxide. In the soft tissue near Champy stainless steel plates, chromium, nickel, iron, and molybdenum were found. Electron microscopy showed titanium dioxide to be mainly deposited between the collagen fibers, whereas stainless steel particles were mainly found in giant cells.

Adolescent↗

PubMed1993

Ultrastructural findings in soft tissues adjacent to titanium plates used in jaw fracture treatment.

The present study was conducted on biopsies from soft tissues overlying titanium miniplates that were used for the treatment of jaw fractures. The aim was to investigate the morphology of liberated titanium particles and cellular or ultrastructural changes in tissues adjacent to the miniplates. Conventional transmission electron microscope (TEM) images were used for ultrastructural investigation and identification of metal-dense particles. The presence of titanium was proved by an increase in the intensity of element-specific, inelastically scattered electrons from the primary beam. The results showed that 5-8 months after insertion of the plates and screws, there was weak cellular activity within the scar tissue overlying the plates without inflammatory cells. Most of the titanium particles were located extracellularly. The ultrastructural appearance of most of these particles suggested that titanium may be shaved off the plates or screws and may undergo cellular uptake and lysosomal degradation. The partially degraded titanium particles are then left in place after the phagocytic cells have been isolated by collagenous fibers and have finally perished.

Bone Plates↗

PubMed1996

Immuno-inflammatory responses in the tissue adjacent to titanium miniplates used in the treatment of mandibular fractures.

The immuno-inflammatory responses to titanium miniplates used in the treatment of mandibular fractures were studied immunohistochemically at light and electron microscope levels. Titanium miniplates were stably situated on the cortical bone surface. In the soft tissue adjacent to the surface of titanium miniplates, double layered connective tissue was observed, which consisted of dense fibrous connective tissue, and relatively loos connective tissue contained proliferated blood vessels with hypertrophied endothelial cells. These vascular endothelial cells expressed HLA-DR, CD54 and CD62P antigens. In some cases they were CD62Epositive. CD68+ and CD11c+ round or spindle-shaped macrophages had infiltrated around the small vessels. Fine titanium particles were observed in the cytoplasm of these macrophages. Both CD4+ and CD8+ T lymphocytes had also infiltrated around venules in some cases. They were CD4+ T lymphocyte-dominant. Immunoelectron microscopically, CD68+ and CD11c+ macrophages contained titanium particles in the lysosomes. Most of the macrophages showed varying degrees of degenerative change. The presence of titanium was confirmed by energy-dispersive X-ray analysis.

Adolescent↗

PubMed1999

The behaviour of titanium as a biomaterial: microscopy study of plates and surrounding tissues in facial osteosynthesis.

Titanium has become the biomaterial of choice for facial osteosynthesis. Titanium is considered a highly biocompatible and corrosion resistant material, although the ultrastructural behaviour of titanium in human tissues after bone fixation is not well documented. A prospective scanning electron microscopy study was carried out on 37 commercially pure titanium miniplates which were removed from 23 patients who had undergone surgery for maxillofacial trauma or deformity. Twenty two cases were used as a control group. Implant-bone specimens were excised using tungsten burs and studied with a scanning electron microscope (Jeol JSM-T-300). Findings at the bone-titanium interface were analyzed, as well as the presence of contaminating bodies on the specimen surface. Biopsies were also obtained from the soft tissues adjacent to 20 miniplates, then sectioned and stained with Haematoxilin-Eosin for histological evaluation by light microscopy. The results showed good ultrastructural osseointegration of the osteosynthesis material in most cases (81.8%). Mobility was found upon removal in 80% of plates which showed clinical complications. A significant correlation was found between the degree of microscopical osseointegration and macroscopic fixation of the plate. Microscopical contamination was found in 100% of the nine plates with intraoral exposure, while only 36% of the 22 miniplates of the control group had contaminating elements (P < 0.001). Thirty-five point one percent of the plates showed hole-like substance loss images, whose size ranged from 10-25 mu. Light microscopy showed granular deposits in soft tissues surrounding the plates in 80% of the 20 specimens investigated. Our findings suggest a higher development of corrosion in titanium than previously reported. These findings are not correlated, however with the clinical complications.

Adult↗

PubMed2000

Osseointegration of endodontic endosseous cones: zirconium oxide vs titanium.

OBJECTIVE: The purpose of this investigation was to investigate the osseointegration of zirconium oxide (ZrO(2)) ceramic cones in comparison with that of titanium cones in apicectomy. STUDY DESIGN: To evaluate the bone/implant interface, 20 ZrO(2) cones and 20 titanium cones were inserted into the mandibles of 4 Göttinger minipigs. During the 6-month healing period, intravital polychrome sequence marking was performed. Qualitative light microscopic, fluorescence microscopic, and quantitative histomorphometric assessment was carried out. Differences between continuous histomorphometric measures were tested through use of a 2-way analysis of variance. RESULTS: Light microscopy revealed zones of direct bone contact with the ZrO(2) and titanium surfaces. Fluorescence microscopy revealed remodeling processes directly adjacent to both material surfaces. There was no significant difference in the distances of the fluorescence bands of each fluorescence marker for either the ZrO(2) surfaces or the titanium surfaces. Quantitatively and histomorphometrically, the mean ratio between the total cone/bone contact and the total cone/fibrous tissue contact was 0.95 (SD 1.10) on the titanium surface (n = 38) and 1.47 (SD 1.12) on the ZrO(2) surface (n = 78; P =.02). CONCLUSIONS: The qualitative results show that the biocompatibility of ZrO(2) was similar to that of titanium. The use of ZrO(2) cones for sealing purposes in resected teeth after apicectomy appears to be acceptable.

Analysis of Variance↗

PubMed1996

Machining efficiency and wear resistance of nickel-titanium endodontic files.

OBJECTIVE: Nickel-titanium endodontic files are more flexible than stainless steel. Little information is reported concerning machining efficiency and wear resistance of nickel titanium. This study assessed the dentin-machining ability and wear resistance of nickel titanium endodontic files in vitro. STUDY DESIGN: The method described earlier to assess machining efficiency and wear resistance of stainless steel files was used. Eight different types and brands of nickel titanium files were studied: Ultra-Flex Hedström, Ultra-Flex K, Mity Hedstrom, Mity K, Mity Turbo, Hedstrom Naviflex NT, NiTiFlex, and Hyflex X-file. Thirty files of each brand were evaluated. One-way ANOVA and t tests were performed to analyze the data. RESULTS: Considerable variation was found in matching efficiency and wear. The best initial machining ability of all nickel titanium instruments was recorded for the Hyflex-X file (0.60 +/- 0.16 mm2); the poorest performance was for the Mity Turbo file, which machined less than one third of the best performing instrument (0.19 +/- 0.12 mm2). CONCLUSIONS: We compared our results with results of a previous study of stainless steel endodontic files and concluded that nickel titanium instruments are as aggressive as or better than stainless steel instruments in removing dentin. They are also more durable than their stainless steel counterparts.

Analysis of Variance↗

PubMed2002

Interactions between cells and titanium surfaces.

The interaction between cells and implant materials is determined by the surface structure and/or surface composition of the material. In the past years, titanium and titanium alloys have proved their superiority over other implant materials in many clinical applications. This predominant behaviour is caused by a dense passive oxide layer which forms within milliseconds in oxidizing media. Titanium dioxide layers of 100 nm thickness were produced on the surface of cp-titanium grade 2, and on an experimental alloy of high vanadium content (Ti1.5Al25V) as a harmful control. The layers were produced by thermal and anodic oxidation and by coating by means of the sol-gel process. The resulting oxide layers were characterized with respect of their structure and chemical composition. In cell tests (proliferation, MTT, morphology, actin staining), the reaction of the cells was examined. It was shown that the sol-gel-produced titanium oxide layer is able to shield the cells from toxic alloying elements, with the result that the cell reaction is influenced only by the thin titanium oxide surface layer and not by the composition of the bulk material.

Actins↗

PubMed2006

Posterior canal wall reconstruction with a composite cartilage titanium mesh graft in canal wall down tympanoplasty and revision surgery for radical cavities.

OBJECTIVES: To investigate posterior external ear canal wall reconstruction with a composite cartilage titanium mesh graft in canal wall down tympanoplasty and revision surgery for open mastoids. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral centre. METHODS: As a preliminary study, 15 selected patients underwent reconstruction of a posterior ear canal wall defect with titanium mesh. Large defects of the posterior external auditory canal wall, resulting from canal wall down tympanoplasty or present in revision surgery, were eliminated by reconstruction using a titanium mesh. The mesh was covered with conchal cartilage and attached to the cortical mastoid bone using 3-mm titanium screws. RESULTS: All patients maintained a normal contour of the external ear canal, without depression, extrusion or infection. There were no failures, based on short-term post-operative controls. However, two procedures had to be revised due to incomplete coverage of the titanium mesh. CONCLUSIONS: This study shows that reconstruction of the posterior ear canal wall with a composite cartilage titanium mesh is a valuable method for preserving the morphology of the external auditory canal in selected cases. Problems occurring in canal wall down tympanomastoidectomy and radical cavities may therefore be avoided. However, long-term results have yet to be evaluated.

Adult↗

PubMedDate not supplied

A removal torque and histomorphometric study of commercially pure niobium and titanium implants in rabbit bone.

Screw-shaped commercially pure (c.p.) niobium and c.p. titanium implants were inserted in rabbit bone. After a healing period of 3 months, a significantly higher removal torque was demonstrated to unscrew the niobium implants (average 32.9 Ncm) compared to the c.p. titanium implants (average 25.3 Ncm). In the histomorphometric part of the study, there were no significant differences in bone-to-metal contact between the 2 implant materials. An average of 41.1% bony contact was demonstrated for the niobium screws compared to an average of 37.2% for the c.p. titanium ones. Our removal torque findings could be related to the differences that we observed between the 2 implant surfaces as indicated by SEM. Since niobium implants showed a more irregular surface topography and niobium is a softer metal than c.p. titanium, this seems the most probable reason for the differences observed in removal torque between the 2 metals. Hypothetically, a more "positive biocompatibility" of the c.p. niobium in comparison to the c.p. titanium remains as another possible reason for the observed differences. However, against such a difference in biocompatibility between c.p. niobium and c.p. titanium, there is the very similar amount of bony contact registered in the histomorphometric analysis.

Animals↗

PubMed1997

The use of implant-supported titanium prostheses for treatment of periodontally compromised patients including functional and orthodontic therapy. Report of 2 cases.

Due to its corrosion resistance and biocompatibility, titanium appears to be an alternative material for implant-supported restorations. However, due to technological difficulties, the clinical application of titanium in implant restorations has been limited. Only after recent progress in technology could the clinical use of ceramo-metal titanium restorations be recommended. The therapeutic repertoire for treating patients with missing teeth has been significantly expanded by modern implant methods. Osseointegrated prostheses have become an integral part of restorative therapy also for periodontally compromised dentitions. This article presents 2 case reports for the use of ceramo-metal implant-supported titanium cast prostheses for restorative treatment of periodontally compromised patients requiring comprehensive treatment involving periodontal, functional, orthodontic and prosthodontic therapy. Favourable clinical results have been obtained and a complication-free service of these reconstructions has been documented throughout a 12- to 24-month observation period. These observations suggest that implant-supported ceramo-metal titanium prostheses may be a valuable part of restorative therapy for periodontally compromised dentitions in that they facilitate restorations with optimal biocompatibility. However, controlled clinical studies are needed to establish the long-term serviceability of these titanium restorations.

Aged↗

PubMed2003

Bone augmentation by means of a stiff occlusive titanium barrier.

It has already been shown that occlusive titanium barriers have osteoconductive properties. These barriers, however, cover only a limited surface area and have only been used in animal experiments. The aim of this study was to evaluate bone neogenesis under a pre-shaped titanium barrier placed over the top of the rabbit skull and the top of highly resorbed edentulous upper-jaw bone in patients. Computed tomography (CT) scans made it possible to pre-shape the titanium barrier according to individual bone shape in human experiments. On the rabbit skull, tissue augmentation of up to 6 mm 1 year after barrier placement was observed, while the original thickness of skull bone was on average between 1.5 and 2.5 mm. The bone, which remained histologically immature for 1 year, grew systematically along the titanium surface, illustrating its osteoconductivity. Even after removal of the barrier, on average, 75.3 and 59.4% of the newly created tissue volume was maintained after 3 and 9 months, respectively. Clinical observations on 10 consecutive patients showed that, in those (5/10) in which the barrier remained unexposed for several months, an increase of the jawbone height and width of up to 16 mm could be observed when the barrier was removed after 12-18 months. As in the rabbits at barrier removal, the bone demonstrated a limited degree of mineralization as ascertained from biopsies. This newly formed osteoid tissue allowed the insertion of 33 screw-shaped titanium implants which in most cases (30/33) successfully osseointegrated to support a fixed prosthesis. The surrounding marginal bone level remained stable even up to 5 years after implant placement. Both animal and clinical data demonstrate that guided bone neogenesis under a subperiosteally placed titanium barrier can reach large volumes.

Adult↗

PubMed2002

The mucosal attachment to titanium implants with different surface characteristics: an experimental study in dogs.

BACKGROUND: Findings from in vitro studies have indicated that the orientation and proliferation of cells on titanium surfaces may be influenced by the topography of the surface on which they are grown. It may be argued, therefore, that differences may occur in the mucosal attachment to titanium implants with different surface roughness. AIM: The present experiment was performed to study the composition of the soft tissue barrier that formed to implants prepared with well-defined smooth or rough surfaces. MATERIAL AND METHODS: Five beagle dogs were used. Four implants made of c.p. titanium were placed in the right edentulous mandibular premolar region. After 3 months, two different types of abutments were connected: one experimental (OA) with a dual, thermal acid-etched surface ('Osseotite'), and one regular (RA) abutment with a 'turned' surface. At the end of a 6-month period during which proper plaque control had been maintained, biopsies including the implant and the surrounding soft and hard tissues were obtained, decalcified and processed for light and electron microscopy. A confocal He-Ne laser profilometer was used to study the surface topography of the abutments. RESULTS: The attachment between the peri-implant mucosa and titanium abutments with either a turned (RA; 'smooth') or acid-etched (OA; 'rough') surface was similar from both a quantitative and a qualitative aspect. The attachment comprised a barrier epithelium and a zone of connective tissue attachment of similar dimension at RA and OA. It was further observed that the 'inner' zone of the connective tissue attachment at both types of abutment was composed of about 30-33% fibroblasts and 63-66% collagen. CONCLUSION: It was demonstrated that the soft tissue attachment that formed to implants made of c.p. titanium was not influenced by the roughness of the titanium surface.

Acid Etching, Dental↗