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PubMed2007

Corpectomy followed by the placement of instrumentation with titanium cages and recombinant human bone morphogenetic protein-2 for vertebral osteomyelitis.

OBJECT: The treatment of vertebral osteomyelitis includes antibiotics with or without surgical intervention. The decision to place instrumentation into an infected spinal column remains controversial. The use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in patients with osteomyelitis is also extremely controversial. The authors review their experience in performing corpectomy and fusion with titanium cages and rhBMP-2 in patients with vertebral instability and/or neurological compromise due to vertebral osteomyelitis. METHODS: Data obtained in 15 patients treated between 2001 and 2005 were included in this analysis. Nine patients presented primarily with axial pain and six with radiculopathy or myelopathy. Seven patients had an associated epidural abscess. The cervical spine was affected in six patients, the thoracic spine in five, and the lumbar spine in four. All patients underwent corpectomy of the involved vertebral bodies; the authors then performed spinal reconstruction, placing a titanium cage-plate system with morcellized allograft/autograft and rhBMP-2. In 10 patients, supplemental posterolateral screw-rod fixation was conducted. A one-level corpectomy was performed in one patient, a two-level corpectomy in 13, and a six-level corpectomy in one. A morcellized allograft and rhBMP-2-filled titanium cage was used in 10 patients, and an autograft and rhBMP-2-filled cage in five patients. The most common pathogen was Staphylococcus aureus. All patients received intravenous antibiotics for at least 6 weeks postoperatively, and life-long antibiotic therapy was required in three patients with coccidiomycoses, candida, and tuberculosis osteomyelitis, respectively. There were no recurrent infections. Radiography demonstrated evidence of fusion in all patients at the last follow-up examination. The mean follow-up period was 20 months. CONCLUSIONS: Corpectomy followed by titanium cage-plate reconstruction and the placement of rhBMP-2 may be a safe and effective treatment for selected patients with vertebral osteomyelitis. This surgical therapy does not appear, at least based on preliminary results, to lead to recurrent hardware infections. Based on the results obtained in this limited series, the authors found that rhBMP-2 can be used in the setting of active infection with excellent fusion rates and without complication. The morbidity associated with the autograft donor site is avoided when using cages. Antibiotic therapy tailored to the specific organism should be continued for at least 6 weeks after surgery, and life-long therapy is required in cases of fungal or tuberculosis infections.

Adult↗
PubMed1994

An experimental model for the assessment of titanium denture casting techniques.

In order to establish the most suitable technique for the construction of cast titanium denture frames, an experimental model was developed for the quantification of casting success. A relatively large wax pattern (36 x 29 x 0.9 mm) was prepared from a grid sheet used for the construction of cast cobalt chromium partial denture frames. The pattern consisted of 100 circles and the number of completely cast circles was counted to obtain a percentage success rate. The castings were complete with pure titanium but incomplete (average 54%) with a titanium alloy. For an inspection of internal defects the radiographic conditions were optimised by adopting a relative density of about 2.0. The procedures described will help in establishing the most suitable casting technique for the construction of titanium denture frames for any casting system employed in a laboratory.

Dental Alloys↗
PubMed1996

Effect of barium in porcelain on bonding strength of titanium-porcelain system.

The bonding strength to titanium, thermal expansion, and bending strength of glassy porcelain containing barium of 5, 10, and 15 mass% were estimated and compared with those of barium-free porcelain, to estimate the effect of barium content on bonding strength to titanium. The three different glassy porcelains containing barium were made by melting at 950 degrees C. The bonding strength of a commercial porcelain to titanium increased with the addition of barium. Bending strength and thermal expansion were not affected by the barium content. Therefore, the addition of barium to porcelain is effective for strengthening the bonding of porcelain to titanium.

Analysis of Variance↗
PubMed2003

The influence of albumin on corrosion resistance of titanium in fluoride solution.

Proteins can interact with corrosion reactions in several ways. In this study, we investigated the effect of albumin on the corrosion resistance of titanium in the presence of fluoride. The effects of the NaF concentration, albumin concentration, and pH on the corrosion characteristics of commercially pure titanium (CP-Ti) were examined by means of electrochemical techniques. The corrosion resistance of titanium decreased as the NaF concentration increased and as pH decreased. The corrosion resistance of titanium in NaF solutions was improved in the presence of albumin. The natural electrode potential was elevated, and the passive current density was reduced by albumin at a concentration of 0.01%. The polarization resistance rose with increased concentrations of albumin in fluoride solution. These results showed that the albumin in saliva and dental plaque affected the corrosion resistance of CP-Ti in fluoride solution.

Albumins↗
PubMed2003

Metallurgical effects on titanium by laser welding on dental stone.

It is not known for certain that dental stone components influence titanium welding. In this study, we investigated metallurgical problems caused by laser welding on dental stones using wrought commercial pure (CP) titanium. A pulsed Nd:YAG laser irradiated a number of specimens' surfaces which were fixed on either a dental hard stone or a titanium plate. The metallurgical properties of the weld were evaluated using the Vickers hardness test, microstructure observation, fractured surface observation and quantitative analysis of oxygen and hydrogen. In the weld formed on the dental stone there was an increase in hardness, the existence of an acicular structure and a brittle fractured surface, and an increase in the oxygen and hydrogen concentrations compared with base metal. In the weld formed on the titanium plate, these changes were not observed. Therefore, it was demonstrated that laser welding on dental stones made the welds brittle.

Analysis of Variance↗
PubMed2004

Dimensional accuracy and surface property of titanium casting using gypsum-bonded alumina investment.

The aim of the present study was to evaluate the dimensional accuracy and surface property of titanium casting obtained using a gypsum-bonded alumina investment. The experimental gypsum-bonded alumina investment with 20 mass% gypsum content mixed with 2 mass% potassium sulfate was used for five cp titanium castings and three Cu-Zn alloy castings. The accuracy, surface roughness (Ra), and reaction layer thickness of these castings were investigated. The accuracy of the castings obtained from the experimental investment ranged from -0.04 to 0.23%, while surface roughness (Ra) ranged from 7.6 to 10.3microm. A reaction layer of about 150 microm thickness under the titanium casting surface was observed. These results suggested that the titanium casting obtained using the experimental investment was acceptable. Although the reaction layer was thin, surface roughness should be improved.

Aluminum Oxide↗
PubMed2004

Machinability evaluation of titanium alloys (Part 2)--Analyses of cutting force and spindle motor current.

To establish a method of determining the machinability of dental materials for CAD/CAM systems, the machinability of titanium, two titanium alloys (Ti-6Al-4V and Ti-6Al-7Nb), and free-cutting brass was evaluated through cutting force and spindle motor current. The metals were slotted using a milling machine and square end mills at four cutting conditions. Both the static and dynamic components of the cutting force represented well the machinability of the metals tested: the machinability of Ti-6Al-4V and Ti-6Al-7Nb was worse than that of titanium, while that of free-cutting brass was better. On the other hand, the results indicated that the spindle motor current was not sensitive enough to detect the material difference among the titanium and its alloys.

Alloys↗
PubMed2006

Comparison of four fluoride etchants in bonding between titanium and a self-curing luting agent.

The purpose of the present study was to investigate the efficacy of four different fluoride etchants in titanium bonding. The etchants were aqueous solutions of 5 wt% sodium fluoride (NaF), ammonium fluoride (NH4F), sodium hydrogen fluoride (NaFHF), and ammonium hydrogen fluoride (NH4FHF). Cast specimens of commercially pure titanium were air-abraded with alumina, etched for 30 seconds, and then primed with a phosphate primer. An acrylic rod was bonded to the specimen with a tri-n-butylborane-initiated self-curing luting agent. Shear bond strengths were determined before and after 10,000 thermocycles. Regarding pre-thermocycling bond strength, there were no significant differences among the etchants. After thermocycling, there was a decrease in bond strength for all groups. Nonetheless, the bond strengths of NaFHF and NH4FHF were significantly higher than those of NaF, NH4F, and non-etched control. In terms of bonding durability between resin and titanium, it was significantly improved when the titanium surface was microscopically roughened with alumina blasting and etching using NaFHF or NH4FHF.

Ammonium Compounds↗
PubMed2006

Titanium casting using commercial phosphate-bonded investments with quick heating method.

The purpose of this study was to investigate the possible use of quick heating method for titanium casting using two commercial investments (Rematitan Plus and Tancovest). The resulting characteristics of the investments with the quick heating method were as follows: residual thermal expansion at the casting temperature was in the range of 0.39 to 0.64%; green strength and fired strength ranged from 4.4 to 10.3 MPa and from 13.8 to 17.6 MPa, respectively. Five full crown titanium castings from each casting condition were obtained using an argon arc melting and gas pressure casting machine. The thickness of cast surface reaction layer was approximately 200 microm, regardless of heating methods or investments. Further, the heating method did not significantly influence either the accuracy or surface roughness of the titanium castings. These results therefore suggested that these commercial investments for titanium could be used for the quick heating method.

Analysis of Variance↗
PubMed1995

[Effect of an additional cathode on the electrolytic-polishing of titanium specimens with non-aqueous electrolyte].

The purpose of this study was to polish electrolytically a large maxillary denture base-shaped titanium specimen with non-aqueous electrolyte. The test specimen was prepared by bending a sheet of titanium plate. An additional cathode was made by cutting off part of a cylindrical cathode. The effects of the shape and position of the additional cathode were investigated. Selected factors of the additional cathode were as follows: the connecting point between the additional cathode and the cylindrical cathode, the end position of the additional cathode, and the distance between the additional cathode and the titanium specimen. An acceptable polished titanium surface was obtained when the connecting point was below the electrolyte surface, the end position of the additional cathode was at a similar level to the bottom of the specimen, and the distance between the additional cathode and the specimen was 10 mm.

Dental Polishing↗
PubMed1998

[Mechanical properties of titanium casting obtained using short-time cast procedure].

The purpose of this study was to investigate the mechanical properties of titanium casting obtained using short-time cast procedure. A commercial phosphate-bonded investment for titanium casting were used. And dumbbell-shaped specimens with phi 2 mm x 14 mm parallel portion were cast according to manufacture instruction and by way of three different short-time cast procedures. Then, micro vickers hardness test and tensile test were performed with these specimens. In the hardness test, the micro vickers hardness of 50 approximately 250 microns deep location from specimen surface was ranged from 192.8 to 259.0 Hv; there were significant difference among both the location factor and the casting procedure factor by the two-way ANOVA (p < 0.05). In the tensile test, tensile strength, yield strength, elastic modulus and elongation were obtained: these tensile properties of short-time cast procedures were not significantly different from those of manufacture instruction. These results indicated that the short-time cast procedure for titanium casting was available in the point of mechanical properties. It was, however, not obvious that how the short-time cast procedures effected the dimensional accuracy of titanium casting. Therefore, further investigation was needed for the practical usage of this method.

Dental Casting Technique↗
PubMed1998

[Fibrinogen affects blood and bone marrow cell functions on titanium in vitro].

Host-derived blood protein adsorption is much more rapid than the migration of cells to foreign surfaces, so the effect of host proteins in blood on blood cells and bone marrow cells was investigated by means of in vitro culturing of blood and bone marrow cells on titanium. A material preincubated with plasma induced high nonspecific esterase (NSE) activity and polymorphonuclear neutrophil (PMN) elastase activity, but neither a serum- nor albumin-coated material had the same effect as the plasma-coated material. Therefore, attention was paid to fibrinogen. On titanium coated with fibrinogen increases in not only NSE activity and PMN elastase activity in blood and bone marrow, but also tartrate-resistant acid phosphatase (TRACP) activity were observed in bone marrow cultures. A decrease in alkaline phosphatase (ALP) activity was also observed in the cultures. These changes of bone marrow cultures were reversed by the addition of recombinant human bone morphogenetic protein-2 to the cultures. These results suggested that bleeding around titanium affects the function of macrophages or neutrophils due to the effect of fibrinogen. Furthermore, it was suggested that this factor may affect the functions of osteoblasts anti osteoclasts around a titanium implant with the inevitable side effects of implantation in bone tissue: bleeding and clotting.

Acid Phosphatase↗
PubMed1998

[The use of titanium mesh plates for graft fixation in mandibular osteoplasty].

Opportunities of the use of mesh titanium plates as fixing devices are considered at reconstruction operations. Data of following up 8 patients with defects of the mandible of various location and extent are analysed. They were operated with reconstruction of the mandible with iliac graft and bone graft fixing with the mesh titanium plates. A technique of the operations is described, a case of successful use of mesh titanium implant modelled by the form of the mandible in repair of the mandible defect. The analysis of long-term results shows the potential efficiency of the use of mesh titanium plates as fixing adaptations in bone plastic operations.

Angiofibroma↗
PubMed1999

[Surgical technique and long-term follow-up of laminoplasty using titanium miniplates].

Problems concerning a spinal deformity due to simple laminectomy and the usefulness of laminoplasty are often reported recently. In our hospital, laminoplasty with titanium miniplates for spinal operations has been used in all cases since 1992. We started to use this method after we encountered several cases of post-operative spinal deformity following multiple-level laminectomy. We reviewed two different subgroups of patients. Group A consisted of 38 cases who were operated on using simple laminectomy. Group B consisted of 32 cases who were operated on using laminoplasty with titanium miniplates. Postoperative spinal deformity occurred in 5 patients of Group A (13%), and in none of Group B (0%). In particular, postoperative spinal deformity occurred in one child case of Group A (33%), and in none of Group B (0%). Laminoplasty is a very simple and efficient technique, and advantages are the presentation of stability of the posterior column and curvature of the laminae, as well as protection of the spinal cord. Compatibility with magnetic resonance imaging (MRI) is another advantage of titanium miniplates, because long follow-up using MRI is always necessary in these cases. In conclusion, laminoplasty with titanium miniplates for spinal operations are a very useful and safe technique.

Aged↗
PubMed1999

Hard, soft tissue and in vitro cell response to porous nickel-titanium: a biocompatibility evaluation.

Porous nickel-titanium (NiTi) alloys have demonstrated bone attachment as well as tissue ingrowth in the past. However, very few studies have compared porous NiTi soft and hard tissue reactions, and in vitro cell response. We therefore have evaluated the general muscle and bone reaction to porous nickel-titanium. The latter material was implanted in rabbit tibias and back muscle, and assessed after three, six and twelve weeks of implantation. Porous NiTi specimens did not cause any adverse effect regardless of both implantation site and post-surgery recovery time. Muscle tissue exhibited thin tightly adherent fibrous capsules with fibers penetrating into implant pores. We observed that attachment strength of the soft tissue to the porous implant seemed to increase with post-implantation time. Bone tissue demonstrated good healing of the osteotomy. There was bone remodeling characterized by osteoclastic and osteoblastic activity in the cortex. This general good in vivo biocompatibility with muscle and bone tissue corresponded very well with the in vitro cell culture results we obtained. Fibroblasts seeded on porous nickel-titanium sheets managed to grow into the pores and all around specimen edges showing an another interesting cytocompatibility behavior. These results indicate good biocompatibility acceptance of porous nickel-titanium and are very promising towards eventual NiTi medical device approbation.

Adipose Tissue↗
PubMedDate not supplied

The effects of the coupling of titanium implants and dissimilar metal abutments on osteoblast differentiation in vitro.

This study evaluated the effect of titanium endosseous dental implants coupled to dissimilar materials on the capacity of preosteoblasts in bone marrow culture to differentiate, to form alkaline phosphatase-positive colonies, and to mineralize. Ten UCLA abutments were cast in each of 4 alloys: Type III gold, ceramometal gold, commercially pure grade I titanium, and titanium-aluminum-vanadium (Ti-6Al-4V); 10 ceramic abutments and 30 sterile Brånemark System implants were also used. Five abutments of each material and 5 implants were incubated individually in rat bone marrow culture, as were 5 of each abutment attached to an implant; bone marrow cultures not containing test samples were used as controls. Following 17 days of culture, the solution potentials of individual abutments (except ceramic), the implant, and the implant-abutment couples were measured in the test medium. One dish of each group of 5 was then stained for bone nodule mineralization; the remainder were quantified by area for alkaline phosphatase staining. Statistical analysis of measured in vitro potentials showed that the uncoupled samples formed 2 groups, and coupled samples formed 3 groups. Analysis of variance for alkaline phosphatase-positive area values showed no significant differences between coupled or uncoupled groups and the control. Normal cell differentiation and morphology as well as a lack of zones of inhibition, were observed. Bone nodule mineralization was evident in all groups. It was concluded that the presence of these commonly used implant abutment biomaterials coupled to titanium endosseous dental implants had no adverse effects on the in vitro capacity of preosteoblasts in marrow to differentiate and to form mineralized bone nodules, despite measured differences in solution potentials.

Alkaline Phosphatase↗
PubMed2000

Perianastomotic colonic tumors after inclusion of titanium or Lactomer in the anastomotic suture line. An experimental study in rats.

OBJECTIVE: The aim of the study was to find out if there are differences in the incidence of colonic tumors at the anastomosis after the inclusion of titanium or the absorbable material Lactomer in the anastomotic suture line. METHODS: Experimental study with 30 male Sprague-Dawley rats, assigned to 1 of 3 study groups: control (colonic anastomosis with interrupted suture); inclusion of titanium (8 mg) in the anastomotic suture line; and inclusion of Lactomer (8 mg) in the anastomotic line. After pharmacological carcinogenesis with 1-2 dimethylhydrazine, perianastomotic tumors were studied in the 20th postoperative week. RESULTS: The inclusion of titanium in the anastomotic line led to more tumors, a larger anastomotic tumoral area and a larger percentage of tumoral area than Lactomer (p < 0.05). The inclusion of Lactomer may have a protective effect against the induction of cancer in the anastomotic area. CONCLUSIONS: Titanium, a material used in mechanical instruments for digestive tract anastomoses, is not an innocuous material. Its presence in the anastomotic line can promote colonic carcinogenesis after induction. The use of mechanical staplers for colonic anastomoses should be relegated to difficult anastomoses that cannot be sewn manually.

1,2-Dimethylhydrazine↗
PubMed1999

A new advanced surface modification technique--titanium oxide ceramic surface implants: the background and long-term results.

This paper discusses the background of advanced surface modification technologies and presents a new technique that forms a titanium oxide ceramic coating with relatively long-term clinical use. Three general techniques are used to modify surfaces: adding or removing material, or changing material already present. Surface properties can also be changed through laser or electron beam thermal treatment without adding or removing material. The new technique outlined in this paper describes producing a corrosion-resistant, 2000 A to 2500 A thick, coherent crystalline oxide ceramic layer on the surface of titanium implants. The layer is grown electrochemically from the bulk of the metal and modified by heat treatment. Compared with implants covered with other coatings, the improved properties of such oxide ceramic-coated implants include the advantages of higher external hardness and greater adherence between the titanium and the ceramic oxide coating. The virtually perfect insulation between the tissue and the metal prevents metal allergy. The coated implants were subjected to various physical and chemical tests and electron microscopy for a qualitative characterization. Finally, these implants (plates, screws for maxillofacial osteosynthesis, and dental root implants) were followed in surgical practice for 10 years. Tests demonstrated and the acquired experience confirmed the good properties of the titanium oxide ceramic-coated implants.

Ceramics↗