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PubMedDate not supplied

[The Mecron-titanium prosthesis].

To answer the question of the duration of cementless hip-endoprostheses 59 Mecron-Titanium-prosthesis were compared with a contingent of 56 prostheses with a Chromium-Cobalt-Molybdenum-stem. The clinical as well as the radiological results are compared in a 2-5 years follow up. It is shown, that the Titanium stem reaches 93.2% "very good" to "satisfactory" results in the Merl d'Aubigné-Scheme the Chromium-Cobalt-Molybdenum-stem in comparison only in 85.71%. The x-ray pictures show, that the Titanium stems cause less sclerosis of the femur than the Chromium-Cobalt-Molybdenum-stems. The radiologic signs of loosening of both stems nevertheless do not correlate with the subjective and clinical results. It has to be mentioned that it was not possible to carry out a complete following up of all patients on the fact that some did non appear to the follow-up-examination.

Chromium Alloys↗
PubMed2000

Nickel-titanium alloys: stress-related temperature transitional range.

The inducement of mechanical stress within nickel-titanium wires can influence the transitional temperature range of the alloy and therefore the expression of the superelastic properties. An analogous variation of the transitional temperature range may be expected during orthodontic therapy, when the archwires are engaged into the brackets. To investigate this possibility, samples of currently used orthodontic nickel-titanium wires (Sentalloy, GAC; Copper Ni-Ti superelastic at 27 degrees C, 35 degrees C, 40 degrees C, Ormco; Nitinol Heat-Activated, 3M-Unitek) were subjected to temperature cycles ranging between 4 degrees C and 60 degrees C. The wires were mounted in a plexiglass loading device designed to simulate clinical situations of minimum and severe dental crowding. Electrical resistivity was used to monitor the phase transformations. The data were analyzed with paired t tests. The results confirmed the presence of displacements of the transitional temperature ranges toward higher temperatures when stress was induced. Because nickel-titanium wires are most commonly used during the aligning stage in cases of severe dental crowding, particular attention was given to the performance of the orthodontic wires under maximum loading. An alloy with a stress-related transitional temperature range corresponding to the fluctuations of the oral temperature should express superelastic properties more consistently than others. According to our results, Copper Ni-Ti 27 degrees C and Nitinol Heat-Activated wires may be considered suitable alloys for the alignment stage.

Alloys↗
PubMed2001

Nickel-titanium mandibular bonded lingual 3-3 retainer: for permanent retention and solving relapse of mandibular anterior crowding.

An innovative technique that involves a nickel-titanium mandibular bonded lingual 3-3 retainer was used to treat relapse of mandibular anterior crowding. The purpose of this study was to demonstrate clinical procedures and to study the effects of a new mandibular bonded lingual 3-3 retainer on the mandibular dental arch. In 18 patients, changes in the irregularity index and in arch dimensions (intercanine width, arch length, and arch depth) were measured against the patients' mandibular dental casts, which were obtained at completion of the previous orthodontic treatment (T(0)). These measurements were taken at the beginning of retreatment (T(1)), and 2 (T(2)), 4 (T(3)), and 6 (T(4)) months after initiation of retreatment. During the period of relapse (T(0)-T(1)), the irregularity index increased from 1.3 to 3.5 mm and the mandibular arch dimensions decreased. Four months after a segment of.018-in nickel-titanium archwire was bonded lingually from canine to canine, the irregularity index decreased from 3.5 to 1.0 mm and the arch dimensions increased and recovered their original posttreatment dimensions. The nickel-titanium archwire was left in place for permanent retention after the period of retreatment. This simple technique effectively solved relapse of mandibular anterior crowding in 4 months. This mandibular bonded lingual 3-3 retainer could be used both actively, to re-treat mandibular anterior crowding without the use of lingual brackets, and passively, for maintenance as a bonded lingual retainer.

Adolescent↗
PubMed2002

Mandibular, sagittal split osteotomies fixed with biodegradable or titanium screws: a prospective, comparative study of postoperative stability.

OBJECTIVE: Comparison of skeletal stability following bilateral sagittal split osteotomy (BSSO) advancement of the mandible fixed with titanium or biodegradable bicortical screws. STUDY DESIGN: Forty consecutive patients underwent mandibular advancement by means of BSSO performed with a standardized technique. In 20 patients rigid fixation was achieved by means of titanium bicortical screws; the other 20 patients were fixed with biodegradable copolymer screws made of poly-L-lactic acid (82%) and polyglycolic acid (18%). Lateral cephalograms were obtained 1 week preoperatively, 1 week postoperatively and after a minimum of 6 months postoperatively. Relevant skeletal points were traced and digitized to evaluate 2-dimensional skeletal change. Changes at each time point were analyzed and compared statistically. RESULTS: There was no statistically significant difference in long-term stability between the 2 groups. No clinical or radiographic evidence of wound healing problems were noted. CONCLUSION: Resorbable poly-L-lactic/polyglycolic acid copolymer bicortical screw fixation of a BSSO is a viable alternative to titanium screws for the fixation of advancement BSSO.

Absorbable Implants↗
PubMed2000

Corrosion-fatigue life of commercially pure titanium and Ti-6Al-4V alloys in different storage environments.

STATEMENT OF PROBLEM: Removable partial dentures are affected by fatigue because of the cyclic mechanism of the masticatory system and frequent insertion and removal. Titanium and its alloys have been used in the manufacture of denture frameworks; however, preventive agents with fluorides are thought to attack titanium alloy surfaces. PURPOSE: This study evaluated, compared, and analyzed the corrosion-fatigue life of commercially pure titanium and Ti-6Al-4V alloy in different storage environments. MATERIAL AND METHODS: For each metal, 33 dumbbell rods, 2.3 mm in diameter at the central segment, were cast in the Rematitan system. Corrosion-fatigue strength test was carried out through a universal testing machine with a load 30% lower than the 0.2% offset yield strength and a combined influence of different environments: in air at room temperature, with synthetic saliva, and with fluoride synthetic saliva. After failure, the number of cycles were recorded, and fracture surfaces were examined with an SEM. RESULTS: ANOVA and Tukey's multiple comparison test indicated that Ti-6Al-4V alloy achieved 21,269 cycles (SD = 8,355) against 19,157 cycles (SD = 3, 624) for the commercially pure Ti. There were no significant differences between either metal in the corrosion-fatigue life for dry specimens, but when the solutions were present, the fatigue life was significantly reduced, probably because of the production of corrosion pits caused by superficial reactions.

Alloys↗
PubMed2000

Prospective clinical 5-year study of ceramic-veneered titanium restorations with the Procera system.

STATEMENT OF PROBLEM: The biocompatibility of titanium has been well documented, but clinical outcomes of ceramic-veneered titanium restorations were not conclusive. PURPOSE: The study presents the results of a 5-year clinical study of individual crowns and fixed partial dentures (FPDs) veneered with a low-fusing ceramic of the Procera system. MATERIAL AND METHODS: All patients at one clinic who required crowns or FPDs during a 2-year period were invited to participate. A total of 260 patients received 333 ceramic-veneered Procera restorations (242 single crowns and 91 FPDs). Clinical registrations were performed annually, and the restorations were evaluated according to the California Dental Association rating system. At the 5-year follow-up, 198 (76%) patients were examined. Most of the loss of patients could be explained. RESULTS: Practically all Procera restorations were judged as satisfactory both at baseline and follow-up examinations. One artificial crown and 1 FPD were remade because of extensive fractures of ceramic veneers. Two FPDs had fractures of a soldered joint, but only 1 FPD was replaced. Some minor complications occurred, such as small porcelain fractures that could be polished (6% of single crowns, 13% of FPDs) and or loosened restorations that were recemented. Other recorded complications were not related to the Procera system but to dental caries, loosened posts and cores, and root fractures. CONCLUSION: Clinical outcomes over a 5-year period for ceramic-veneered titanium restorations with the Procera system were favorable.

Adult↗
PubMed2003

Dimensional changes of one-piece frameworks cast from titanium, base metal, or noble metal alloys and supported on telescopic crowns.

STATEMENT OF PROBLEM: The dimensional accuracy of 1-piece frameworks cast from commercially pure titanium and used to accommodate supporting telescopic crowns has not been demonstrated. PURPOSE: To compare dimensional changes incurred in frameworks cast from commercially pure titanium, a cobalt-chromium alloy, and a noble metal (gold) alloy. MATERIAL AND METHODS: This study was based on 2 different models, both prepared to receive telescopic crowns: 1 with 4 dies, designed to measure dimensional changes of the castings in the horizontal plane; and another with 2 dies, designed to measure dimensional changes in the vertical plane. As variables for the 2-die models, the palatal shape (16- and 20-mm radius) as well as the palatal depth (20-mm radius with the smallest palatal depth of 8 mm, 16-mm radius with flat palate and palatal depth of 10 mm, 16-mm radius with greatest palatal depth of 16 mm) were studied. Ten specimens each were fabricated from a commercially pure titanium, a cobalt-chromium alloy, and a gold alloy. All castings were fabricated under standardized conditions. All measurements were taken with a computer-controlled measuring microscope at the margins of the simulated telescopic crowns; these served to calculate the ideal midpoint from which the distances between the telescopic crowns were measured. The positional relation of the telescopic crowns was determined in horizontal and vertical directions. The measurements of the cast models were compared with measurements of the original model. The distances between the dies and the angles of the chosen telescopic crowns were calculated in fractions of millimeters and the angles were measured in degrees. The Kruskal-Wallis test and the Mann-Whitney U test were used for statistical analysis. The level of significance was alpha=5%. RESULTS: With the following exceptions, none of the 3 alloy types showed significantly different results. With the 4-die model, all 3 alloys showed significant variations from the original model for chosen lengths (P=.001). For those lengths, the dimensional accuracy of the noble metal alloy was approximately 99.9% of the length of the original; for the 2 other alloys, an average value of 99.4% was determined. With the 2-die models the calculated angle was significantly different from the original model for all alloys (P=.001 or.000), independent from the palatal vault and depth. Significant differences from the original model were also found for the distance between the 2 telescopic crowns with all alloys for the 2-die model with a 16-mm depth palatal vault and a 16-mm radius (P=.001,.006, or.009). CONCLUSIONS: Within the limitations of this study, the significant different dimensional changes both for the 4-die models and the 2-die models did not depend on the type of alloy. The 2-die models demonstrated significant dimensional changes resulting from the palatal geometry of the corresponding test models; the 4-die models demonstrated a tendency to contract toward the geometric center.

Chromium Alloys↗
PubMed1991

Results of a multicenter study of the modified hook-titanium Greenfield filter.

Initial efforts to modify the stainless steel Greenfield filter for percutaneous insertion led to development of a titanium Greenfield filter, which could be inserted by use of a 12F carrier. This device functioned well as a filter but had an unacceptable 30% rate of migration, tilting, and penetration. Therefore a titanium Greenfield filter with modified hooks was developed and has been tested in 186 patients at 10 institutions. Successful placement occurred in 181 (97%); placement of the remainder was precluded by unfavorable anatomy. A contraindication to anticoagulation was the most frequent indication for insertion (75%). All but two were inserted percutaneously, predominantly via the right femoral vein (70%). Initial incomplete opening was seen in four patients (2%), which was corrected by guide wire manipulation and asymmetry of the legs in 10 (5.4%). Insertion site hematoma occurred in one patient, and apical penetration of the cava during insertion occurred in a second patient. Both events were without sequelae. Follow-up examinations were performed at 30 days at which time 35 deaths had occurred. Recurrent embolism was suspected in six patients (3%) and two of three deaths were confirmed by autopsy. Filter movement greater than 9 mm was seen in 13 patients, (11%) and increase in base diameter greater than or equal to 5 mm was seen in 17 patients (14%). CT scanning showed evidence of caval penetration in only one patient (0.8%). Insertion site venous thrombosis was seen in 4/46 (8.7%) patients screened. The modified hook titanium Greenfield filter is inserted percutaneously or operatively through a sheath, eliminating concern for misplacement from premature discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2003

Effects of foliar sprays containing calcium, magnesium and titanium on plum (Prunus domestica L.) fruit quality.

An experiment was performed in which Ti(4+)-ascorbate was sprayed onto plum trees in several combinations with other commercial compounds containing Ca2+ and Mg2+ to study the effects on the commercial quality of fruits, with special focus on improving their resistance against postharvest handling damage. All the treatments containing titanium increased the tree performance (branch elongation, flowering and fruit setting intensities) and fruit size. At harvest fruits from the Ti-treated trees showed improved resistance to compression and penetration, as well as a decrease in weight-loss during postharvest storage. A similar response was obtained for the external colour, though all the treatments seemed to delay somewhat the apparent ripening status. Nevertheless, the fruits from Ti-treated trees showed a better behaviour in the evolution of the colour parameters during storage than did the control fruits. Titanium application significantly increased the calcium, iron, copper and zinc concentrations in peel and flesh. This improvement in the calcium absorption is explained as a consequence of the beneficial effect of titanium on the absorption, translocation and assimilation processes.

Calcium↗
PubMed2004

Type 2 thyroplasty for spasmodic dysphonia: fixation using a titanium bridge.

OBJECTIVE: In order to facilitate surgery for spasmodic dysphonia, i.e. type 2 thyroplasty, a device was designed to fix the incised edges of the thyroid cartilage firmly. MATERIAL AND METHODS: Various types and sizes of titanium bridge were developed for clinical use. RESULTS: The results of surgery for spasmodic dysphonia were satisfactory in all 10 cases in which the new titanium bridge was used. No complications have been encountered to date. CONCLUSION: Type 2 thyroplasty for spasmodic dysphonia was made easier to perform using the new titanium bridge, and more stable fixation of the reconstructed thyroid cartilage was achieved.

Humans↗
PubMedDate not supplied

Titanium particles identified by energy-dispersive X-ray microanalysis within the lungs of a painter at autopsy.

A 72-year-old male painter, who complained of his "lungs burning" for 2 weeks, died suddenly. Autopsy examination revealed severe coronary atherosclerosis with plaque rupture as the cause of death. Examination of the lungs revealed emphysema, interstitial fibrosis, and multinucleated giant cells with intra- and extracellular brown-black, crystalline, polarizable foreign material. Energy-dispersive X-ray microanalysis showed the material to contain titanium, aluminum, silicon, and iron. An increased incidence of respiratory disease has been reported in professional painters. Titanium is widely used as a pigment in the manufacturing of commercial paints. Cases of pneumoconiosis and alveolar proteinosis have been described in painters in which analysis of lung tissue revealed increased levels of titanium. This case is presented as an example of a rarely reported phenomenon, which may have clinical implications for evaluation and management of lung disease in painters.

Aged↗
PubMed2001

Immunohistochemical study of clinical skin-penetrating titanium implants for orthopaedic prostheses compared with implants in the craniofacial area.

The technique of using osseointegrated bone-anchored percutaneous titanium implants in the rehabilitation of patients with amputated limbs has recently been introduced at the Brånemark Osseointegration Centre in Göteborg. The new method is based on an implantation technique that is well-established for anchorage of bone-conductive hearing aids and craniofacial prostheses. The soft tissues around skin-penetrating titanium implants used to anchor orthopaedic prostheses were evaluated histochemically using quantitative analyses. The implants had been in clinical use for between 6 to 24 months. The number of inflammatory cells was higher in the area close to the interface than in the area distant from the skin-penetrating site, and higher than in the corresponding controls. The current data was also compared with corresponding data from tissue around skin-penetrating craniofacial implants. The number of inflammatory cells was lower in the orthopaedic samples than in the craniofacial specimens. We conclude that skin-penetration of orthopaedic implants is as safe as when titanium implants are used for craniofacial rehabilitation, which is a clinically well-established procedure.

Adult↗
PubMed1998

Use of titanium dental implants as an integrated part of a CLP protocol.

The problem of edentulousness in the cleft area of patients with cleft lip and palate was formerly resolved with a conventional fixed bridge construction, but this approach did not always prove optimal. Nowadays, in these patients the bridge can be substituted by a crown on an osseointegrated titanium implant fixture. The concept of dental rehabilitation using titanium implants has gradually merged into our routine treatment for patients with cleft lip and palate. In this report we describe our surgical technique using osseointegrated titanium implants and evaluate our result in patients with cleft lip and palate. Sixteen patients with cleft lip and palate, 11 men and five women, were divided into two groups: group 1 consisted of six patients who did not need bone grafting prior to the fixture installation, and group 2 comprised 10 patients who had additional bone grafting three months before the fixture installation. Abutments were applied six months after fixture installation. Dental crowns and fixed bridges were then constructed. All patients were seen on regular follow-up visits. Routine roentgenograms were obtained preoperatively and when the abutments were applied. Photographs were taken at these occasions and also after the prosthodontic work was completed. Of a total of 31 fixtures, all except two were osseointegrated at the time of the abutment connection, and the remaining 29 have all been functional during the observation period, giving a success rate of 93%. In group 1 all fixtures (100%) were osseointegrated. The non-integrated fixtures were found in group 2 giving a success rate of 91% in this group. The mean follow-up time after fixture installation was six years and three months, and the mean observation time with loaded fixtures was five years and six months.

Adolescent↗
PubMed2002

Numerical analysis of titanium cast devices for dental implantology.

The present work pertains to a numerical investigation of the casting process of titanium devices adopted for dental implantology. The analysis of the titanium framework that connects different abutments, in a multi-implant configuration, is performed evaluating the characteristics of the material that depend on the manufacturing procedure. The connecting bar is obtained by a foundry process that is controlled through a numerical simulation by using a control volume technique. This analysis leads to the possibility to have detailed information on the process and control of the quality of the microstructure of the material produced that proves to be highly beneficial for defining mechanical properties. On the basis of the results obtained, a subsequent stress analysis can be performed, addressed to highlight critical conditions. Functional response of the whole bar-implant framework is studied by means of a numerical model, based on the geometric element method. This technique is particularly suited for describing complex morphology of the implant site. The present approach addresses a higher quality definition of the reliability of the device used in dental practice and represents a valuable tool in assisting optimisation procedures pertaining to manufacturing. In fact, the improvement of titanium devices is intended not only with regard to their mechanical performances, but also to requirements pertaining to manufacturing and clinical practice.

Computer Simulation↗
PubMed2001

Influence of rhBMP-2 on rat bone marrow stromal cells cultured on titanium fiber mesh.

Titanium (Ti) fiber mesh is a candidate scaffold material for the creation of bone graft substitutes (BGS). Two densities (3.54 x 10(4) cells/cm(2) [LD or low density] and 3.54 x 10(5) cells/cm(2) [HD or high density]) of rat bone marrow stromal cells were seeded on Ti-fiber mesh discs. Cells were cultured for up to 16 days, 7 days of which the cells were in the presence of various concentrations of rhBMP-2 (0, 10, 100, and 1,000 ng/mL) in order to evaluate osteogenic expression. Scanning electron microscopy (SEM), light microscopy (LM), energy dispersive spectroscopy (EDS), DNA and calcium (Ca) content measurements, and x-ray diffraction (XRD) analysis were performed. SEM and EDS evaluation showed that a confluent layer of cells was present on top of the meshes together with collagen bundles and calcified globular accretions. Light microscopical evaluation showed a densely stained layer in the upper part of the mesh. SEM and Ca content measurement showed that calcification starts at 8 days. In addition, it was demonstrated that DNA content peaked at 8 days. LM, SEM, and Ca content evaluation revealed positive effects of increasing the cell seeding density, the rhBMP-2 concentration and the culture time on mineralization. Increasing the cell seeding density also showed a positive effect on DNA content. No effects of rhBMP-2 concentration were seen on DNA content. Finally, XRD revealed that the deposited matrix contained a precipitate of a stable calcium phosphate phase. We conclude that (1) titanium fiber mesh sustains excellent osteogenic expression in vitro, (2) increasing the cell seeding density has a positive effect on osteogenic expression in titanium mesh in vitro, and (3) in high density specimens, rhBMP-2 concentrations of 100 ng/mL and 1,000 ng/mL stimulate extracellular matrix calcification in a dose-responsive manner.

Animals↗
PubMed2003

Laparoscopic cholecystectomy: retrospective comparative evaluation of titanium versus absorbable clips.

We present a retrospective study of the use of titanium and absorbable clips during laparoscopic cholecystectomy. The aim was to determine any differences in outcome and costs. From January 1999 to February 2002, 690 patients who had successfully undergone a laparoscopic cholecystectomy were reviewed. According to the type of clip, we retrospectively identified two groups of patients: 199 in whom the surgeons had used absorbable clips (absorbable clip group, ACG) and 491 in whom the surgeons had used titanium nonabsorbable clips (titanium clip group, TCG). Data about demographics, operation, results, complications, and follow-up were collected and matched in the two groups. Demographics, concomitant surgery, and the American Society of Anesthesiologists (ASA) status were comparable between the two groups. Although the proportions of cases requiring urgent operation, intraoperative cholangiography, use of a fourth trocar, and use of drainage suction were similar, the difficulty score of the operation was lower (6.3 vs. 7.0, P =.03) and the operative time was shorter (44 vs. 61 minutes, P <.0001) in the ACG than in the TCG. Complications, hospital stay, and long-term results were satisfactory and comparable between the two groups. No correlation was found between clip type and the incidence of biliary tree injuries, bleeding, wound infection, or readmission. The cost of the two types of clips varied slightly (90 euros for each procedure). Despite the fact that absorbable clips are theoretically less likely to cause complications than metallic ones, we were not able to demonstrate any clinical advantage during laparoscopic cholecystectomy in this retrospective study. Furthermore, the results suggest that absorbable clips are preferred when the cholecystectomy presents fewer difficulties.

Adult↗
PubMedDate not supplied

Influence of RGD-loaded titanium implants on bone formation in vivo.

Little is known about the ability of peptide-coated surfaces to influence cell responses in vivo. Many studies have demonstrated that peptide-modified surfaces influence cell responses in vitro. Integrins, which bind specifically short peptide sequences, are responsible for these cell responses. In this way, information can be transmitted to the nucleus through several cytoplasmic signaling pathways. The peptide sequence Arg-Gly-Asp (RGD peptide) plays an important role in osteoblast adhesion. The present study was designed to investigate new bone formation in a porous titanium (Ti) fiber mesh implant, which was coated with cyclic RGD peptide. The RGD-Ti implants were inserted into the cranium of a rabbit and were compared with porous titanium fiber mesh disks without RGD sequence (Ti) and with an open control defect. Histologic and histomorphometric examinations were performed 2, 4, and 8 weeks postoperatively. A significant increase in bone formation, or bone ingrowth, was seen in the RGD-Ti group compared with the Ti group after 4 and 8 weeks. All control defects stayed open in all three periods. It was concluded that the use of cyclic RGD peptide in combination with titanium fiber mesh has a positive effect on bone formation in vivo in a rabbit animal model.

Animals↗