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PubMed2004

A comparative study of the static and kinetic frictional resistance of titanium molybdenum alloy archwires in stainless steel brackets.

This ex vivo study compared the static and kinetic frictional resistance of eight different archwires tested in a single, stainless steel, zero base 0.022 x 0.028 inch (0.56 x 0.711 mm) slot standard edgewise bracket. The archwires evaluated were 0.019 x 0.025 inch (0.483 x 0.636 mm) in dimension, manufactured from the following alloys: beta titanium (TMA), 'low friction' coloured beta titanium (aqua, honeydew, purple and violet), ion-implanted beta titanium, Timolium and a stainless steel control. Prior to friction testing, bracket and archwire dimensions were measured by direct digital imaging via a desktop computer linked to a binocular light microscope. Frictional force was evaluated using an Instron universal testing machine. All experiments were carried out at room temperature, with no ligation, in the dry state with 20 degrees of added torque. The results demonstrated that static and kinetic friction were statistically significant (P < 0.001) for all archwire types. Ion-implanted and standard TMA archwires were found to have no significant advantage over stainless steel. The archwire alloys may be ranked as follows: stainless steel produced the lowest frictional resistance followed by honeydew, ion-implanted TMA and Timolium, with aqua, purple and violet producing frictional resistance values as high as standard TMA. It was also found that the percentage difference between the archwire and bracket slot dimensions claimed by the manufacturers and those measured in this experiment produced tolerances ranging from +5.37 to -6.67 per cent.

Analysis of Variance↗
PubMed2004

Biomonitoring of titanium, mercury, platinum, rhodium and palladium in dental health care workers.

BACKGROUND: In dentistry, titanium, mercury, platinum, rhodium and palladium are used to produce dental fillings. Therefore, dental workers who apply such materials may be exposed to these metals. METHODS: The study concerned 40 healthy subjects-20 controls and 20 dental health care workers-to determine serum and urinary levels of the aforementioned metals by inductively coupled plasma mass spectrometry. RESULTS: Mean urinary and serum titanium did not reveal statistically significant differences in the two groups. The very low urinary and serum levels of mercury, platinum, rhodium and palladium prevented us from making a statistical evaluation between the two groups. CONCLUSIONS: We did not find a significant increase in serum and urinary titanium levels in dental health care workers. Measurement of mercury, platinum, rhodium and palladium in urine and serum was not useful in determining occupational exposure.

Adult↗
PubMed1994

Sinus histiocytosis of pelvic lymph nodes after hip replacement. A histiocytic proliferation induced by cobalt-chromium and titanium.

Six men who had undergone hip replacements for degenerative joint disease or trauma subsequently had radical prostatectomies or cystoprostatectomies with bilateral pelvic lymph node dissections for adenocarcinoma of the prostate or transitional cell carcinoma of the urinary bladder. The hip prostheses implanted in three patients were known to contain cobalt-chromium alloy and titanium. The pelvic lymph nodes ipsilateral to the hip prosthesis in five patients and the bilateral pelvic nodes in the only patient with bilateral hip prosthesis had dark brown or black cut surfaces. These lymph nodes did not contain carcinoma but showed florid sinus histiocytosis characterized by large polygonal histiocytes filling and expanding sinuses and interfollicular regions. The foamy histiocytes contained cobalt-chromium and titanium microparticles by light microscopy, ultrastructure, and energy-dispersive x-ray microanalysis. The lymph nodes uninvolved by the histiocytic reaction lacked the heavy metal microparticles. Four cases were found to have a small number of polyethylene particles, which might have contributed to the histiocytic response. By immunohistochemistry, the foamy cells displayed immunoreactivity for lysozyme, alpha-1-antitrypsin, alpha-1-antichymotrypsin, and cathepsin D, providing additional support for their histiocytic derivation. To our knowledge, this is the first time that microparticles of cobalt-chromium and titanium that migrate from hip prostheses to pelvic lymph nodes have been shown to elicit a distinctive type of florid sinus histiocytosis. Pathologists should be aware of this characteristic foreign-body tissue response to avoid confusion with other types of sinus histiocytosis or with metastatic carcinoma.

Aged↗
PubMed1996

A comparative biomechanical analysis of resorbable rigid fixation versus titanium rigid fixation of metacarpal fractures.

Linear (two-dimensional) and three-dimensional (3D) plating systems (Poly-Medics) composed of the resorbable copolymer of polyglycolic acid (PGA) and poly-l-lactic acid (PLLA) (Lactosorb) were studied in vitro. The plates were applied to osteotomized fresh frozen human cadaveric metacarpal bones that were then tested for torsional rigidity and three-point bending strength and rigidity. The results were compared to those from another study of two low-profile titanium plating systems (Leibinger and Synthes). Analysis of variance revealed that the linear-flat Lactosorb plate and screws had apex dorsal rigidity and force-to-displacement measurements equal to all but two of the titanium plates (3D). The 3D-flat Lactosorb plate had the highest torsional rigidity of the resorbable system, but it was only moderately rigid compared to the titanium plating systems. This in vitro biomechanical study of the copolymer PGA-PLLA plating system indicates that, in clinical applications, it may be better suited for metacarpal fractures rather than proximal phalangeal fractures due to the lower demands of torsional loading compared to apex bending.

Biomechanical Phenomena↗
PubMed1999

A biomechanical analysis of the orbitozygomatic complex in human cadavers: examination of load sharing and failure patterns following fixation with titanium and bioresorbable plating systems.

The orbitozygomatic complex (OZC) and zygomatic arch act as key buttresses in the restoration of midfacial projection and width in the treatment of panfacial fractures, yet little is known about the biomechanical and deformational forces placed on this region under applied load conditions. The aims of this project were (1) to study the stress-force relationships and load sharing of the intact human OZC under subfailure loads, (2) to assess load sharing and breaking strength of the OZC when intact and after four-point miniplate fixation with either titanium (1.2 and 1.7 mm) or bioresorbable (1.5 and 2.0 mm) systems, and (3) to analyze failure patterns. Using the MTS machine, fresh frozen human skulls stripped of soft tissue underwent loading with subfailure and failure forces directed in a standard fashion. Electrical resistance gauges applied directly to local and remote bony buttresses demonstrated temporary deformation at local (zygomatic arch, lateral and inferior orbital rim) and remote (supraorbital rim) buttresses under subfailure loading conditions. Breaking strength of the OZC (N = 10) measured before and after four-point application of 1.2- or 1.7-mm titanium or 1.5- or 2.0-mm bioresorbable miniplates demonstrated a significant (p < 0.05) decrease compared with intact controls. Surprisingly, the 2.0-mm bioresorbable miniplate construct provided only 13% of the intact breaking strength of the OZC compared with 39% for the 1.7-mm titanium system (p < 0.05). Plate bending or breakage was responsible for failure of the OZC following rigid fixation. Biomechanical testing of the OZC demonstrates (1) load sharing at regional and remote bony buttresses, (2) significant decreases in breaking strength following miniplate fixation, and (3) deformation of miniplates as a primary cause of failure under load conditions. Data generated from this project may be useful with regard to optimizing fixation of the OZC in the context and treatment of panfacial fractures.

Absorbable Implants↗
PubMed1999

Biokinetics and dosimetry of titanium tritide particles in the lung.

Doses of internal radiation from inhalation of metal tritide aerosols are potentially a major radiation protection problem encountered by nuclear industry workers. Based on results of experiments with rats intratracheally instilled with titanium tritide particles and on a self-absorption factor of beta particles determined by a numerical method, a biokinetic model was developed for inhaled particles of titanium tritide. Results showed that lung burdens of the tritide are well represented by a two-component exponential equation; biological half-lives derived for the retention of 3H in lung were 0.81 d and 66 d. The tritium clearance rate via urine or feces was described by bi-phase exponential components. At 121 d after instillation, 82% of the initial lung burden of 3H had been eliminated, of which 37% was excreted in urine, 29% via feces, and 16% through exhaled air. Based on simulation results of the biokinetic model, the cumulative absorbed dose and committed effective dose were calculated as well as the annual limit of intake (ALI) and derived air concentration (DAC). The ALI and DAC values for titanium tritide were a factor of 5 lower than values for tritiated water. This information will be useful in developing new guidelines for radiation protection purposes.

Administration, Inhalation↗
PubMedDate not supplied

Pin removal in slipped capital femoral epiphysis: the unsuitability of titanium devices.

In an effort to predict which slipped capital femoral epiphysis fixation devices might cause fewer retrieval problems, 27 consecutive implant-retrieval procedures were reviewed, and mechanical tests using many currently available devices were performed. Problems occurred with both stainless steel and titanium devices if implanted for > 1 year. This tendency for increased problems was statistically significant for the titanium group, and analysis of a retrieved titanium screw showed evidence of osseointegration (direct bone-metal contact at > 90% of the interface) using backscattered image scanning electron microscopic analysis. These clinical data and data from mechanical testing suggest that stainless steel screws or trocar-tipped Steinmann pins are better suited for fixation of slipped capital femoral epiphysis.

Adolescent↗
PubMedDate not supplied

Flexible titanium nailing for the treatment of the unstable pediatric tibial fracture.

Tibia fractures in the skeletally immature patient can usually be treated without surgery. The purpose of this study was to assess the use of flexible titanium nails in the tibia that requires operative stabilization. Over a 5-year period, 16 unstable tibia fractures in 14 patients were treated with flexible titanium intramedullary nails. All charts and radiographs were reviewed. The average age was 10 years 4 months. There were three open fractures. All fractures healed. Closed injuries obtained union by an average of 8 weeks, open fractures by an average of 15 weeks. There were no malunions. The average follow-up was 1 year 5 months. There were no instances of growth arrest, remanipulations, or refracture. In the unstable pediatric tibia fracture, flexible titanium nails are an effective treatment to obtain and maintain alignment and stability.

Bone Nails↗
PubMed2000

Torsional properties of stainless-steel and nickel-titanium files after multiple autoclave sterilizations.

This study tested the hypothesis that multiple sterilizations of endodontic stainless-steel and nickel-titanium files will lead to a continuous decrease in the resistance of files to separation by torsion. One hundred stainless-steel and 100 nickel-titanium #30 K-type files were divided into 20 groups of 10 and sterilized in increments of 10 cycles, using a full cycle and a fast cycle autoclave. These files were tested by twisting each of them in a clockwise direction until fracture (torque g-cm). Samples of the fractured files were embedded in an epoxy resin and polished for Knoop hardness tests. In addition, the samples were chemically etched to reveal changes in microstructure. The findings of this study indicate that neither the number of sterilization cycles nor the type of autoclave sterilization used affects the torsional properties, hardness, and microstructure of stainless-steel and nickel-titanium files.

Acid Etching, Dental↗
PubMed2003

Evaluation of single-use rotary nickel-titanium instruments.

The purpose of this study was to analyze the number and types of defects observed in single-use, rotary nickel-titanium instruments. Every ProFile Series 29.04 taper nickel-titanium instrument used during a 4-week period in an endodontic specialty practice was collected. All instruments were new and were used by experienced clinicians during a single patient visit. The instruments were routinely used in a crown-down manner with RC Prep lubrication and copious irrigation. The instruments were used in a MicroMega 324 air motor in a 6:1 gear reduction contra-angle at 333 rpm. The instruments were collected, ultrasonically cleaned, sterilized, and inspected at x16 magnification. Torsional, flexural, and fracture defects were recorded and statistical analysis was performed using the Kruskal-Wallis one-way analysis of variance. A total of 786 ProFile Series 29 nickel-titanium rotary instruments were evaluated; 115 (14.63%) showed some type of defect after one clinical use. Size 3 instruments had the highest defect rate (22.66%) followed by size 5 (17.30%), size 2 (17.24%), and size 4 instruments (16.10%). However, there was no statistically significant difference. The size 6 and size 7 instruments showed minimal defects (2.38% and 4.76%, respectfully). Seven of 786 files had fractured (0.891%). There was no statistically significant difference in the type of failure seen within each file size. This study does show that defects can occur even with new files in the hands of experienced endodontists, and for absolute safety a single-use approach should be followed.

Analysis of Variance↗
PubMed2003

Evaluation of an ultrasonic technique to remove fractured rotary nickel-titanium endodontic instruments from root canals: an experimental study.

The use of nickel-titanium rotary instruments in endodontic practice is increasing. One frequently mentioned problem is fracture of an instrument within the root canal. To date, there is no consistently safe and successful technique for removing these fractured instruments. This study evaluates the use of an ultrasonic technique to remove fractured rotary nickel-titanium instruments from narrow, curved canals in both simulated (resin blocks) and mesiolingual canals of extracted mandibular first molars. A technique using ultrasonic tips, combined with the creation of a "staging platform" and the use of the dental operating microscope, was consistently successful and safe at removing fractured rotary nickel-titanium instruments from curved root canals, when some part of the fractured instrument segment was located in the straight portion of the canal. When the fractured instrument segment was located entirely around the curve, the success rate was significantly decreased and major canal damage often occurred.

Analysis of Variance↗
PubMed1989

Anterior and posterior cervical spine fixation using titanium implants to facilitate magnetic resonance imaging evaluation.

Magnetic resonance (MR) imaging of the cervical spine is useful in the evaluation of both acute and chronic injuries to the spinal cord and meninges as well as in demonstration of mechanical impingement on the spinal canal and nerve roots. Anterior or posterior plate fixation of unstable cervical spine injuries has limited the postoperative use of MR imaging due to the extensive magnetic field distortion produced by the stainless steel implants commonly used in these procedures. We have compared titanium implants in a cadaver against stainless steel implants in two patients and show no significant MR artifacts produced in the spinal canal by titanium plates as opposed to extensive image distortion and obliteration by the steel plates. We recommend consideration of titanium (Ti6A14V) as a substitute for stainless steel in cervical spine fixation to preserve the option of subsequent examination by MR scanning.

Bone Plates↗
PubMed1995

Titanium anchors for the repair of rotator cuff tears: preliminary report of a surgical technique.

We used titanium anchors for the surgical repair of rotator cuff tears in 34 selected patients, all of whom were < 60 years of age, had good bone quality, and had no known metabolic bone diseases. Nine tears were repaired within 6 months, 15 within 6-12 months, and 10 later than 12 months after injury. Tear size was graded as small (10 patients), medium (15 patients), and large (nine patients) during open operation. After 6-24 months of follow-up, 30 patients reported satisfactory pain relief, function, active forward flexion, and muscle strength [18 excellent and 12 good results based on the University of California at Los Angeles rating system (UCLA scores)]; there were no implant failures (p < 0.001). Two patients had unsatisfactory function but good relief of pain, whereas two patients were dissatisfied with their overall result (four poor results based on UCLA scores). Although trans-bone suturing is presently the most common and successful surgical technique for rotator cuff tears, we found that use of titanium anchors shortens operative time and has results comparable with the traditional technique. Titanium anchors should not be used when bone quality is poor or good patient compliance is doubtful. They are also contraindicated, as our four poor results indicate, when the tear is old (> 6 months) and large (diameter > 5 cm with significant tissue degeneration).

Adult↗
PubMed2002

Revision ossicular reconstruction with the titanium Kurz prosthesis.

OBJECTIVE/HYPOTHESIS: One European multicenter study has reported favorable outcomes after ossicular reconstruction with the titanium Kurz prosthesis. At the time of this study, however, no study has analyzed its outcomes when used for reconstruction after prior failure with another implant (revision reconstruction). The study reports our experience with the titanium Kurz prosthesis for revision ossicular reconstruction. STUDY DESIGN: A retrospective review was made of all revision ossicular reconstructions at our institution from October 1998 to September 2001. METHODS: Seventeen cases were reviewed. Patients were divided into two groups: patients who underwent revision ossicular reconstruction with the Kurz prosthesis and patients who underwent revision ossicular reconstruction with another prosthesis (the "other" group). Audiograms were reviewed and air-bone gaps were calculated for each patient. RESULTS: The average postoperative air-bone gap after Kurz revision was 15.6 dB, a statistically significant improvement over the average postoperative air-bone gap from the "other" revision group (P =.022). CONCLUSION: The titanium Kurz prosthesis has been an effective implant at our institution for revision ossicular reconstruction. Future research should focus on a prospective, randomized trial comparing the Kurz prosthesis with other prostheses currently in use.

Adolescent↗
PubMed2003

Functional results after external vocal fold medialization thyroplasty with the titanium vocal fold medialization implant.

OBJECTIVES/HYPOTHESIS: A persistent insufficiency of glottal closure is mostly a consequence of a unilateral vocal fold movement impairment. It can also be caused by vocal fold atrophy or scarring processes with regular bilateral respiratory vocal fold function. Because of consequential voice, breathing, and swallowing impairments, a functional surgical treatment is required. The goal of the study was to outline the functional results after medialization thyroplasty with the titanium vocal fold medialization implant according to Friedrich. METHODS: In the period of 1999 to 2001, an external vocal fold medialization using the titanium implant was performed on 28 patients (12 women and 16 men). The patients were in the age range of 19 to 84 years. Twenty-two patients had a paralysis of the left-side vocal fold, and six patients, of the right-side vocal fold. Detailed functional examinations were executed on all patients before and after the surgery: perceptive voice sound analysis according to the "roughness, breathiness, and hoarseness" method, judgment of the s/z ratio and voice dysfunction index, voice range profile measurements, videostroboscopy, and pulmonary function tests. In case of dysphagia/aspiration, videofluoroscopy of swallowing was also performed. The respective data were statistically analyzed (paired t test, Wilcoxon-test). RESULTS: All patients reported on improvement of voice, swallowing, and breathing functions postoperatively. Videostroboscopy revealed an almost complete glottal closure after surgery in all of the patients. All voice-related parameters showed a significant improvement. An increase of the laryngeal resistance by the medialization procedure could be excluded by analysis of the pulmonary function test. CONCLUSIONS: The results confirm the external medialization of the vocal folds as an adequate method in the therapy of voice, swallowing, and breathing impairment attributable to an insufficient glottal closure. The titanium implant offers, apart from good tissue tolerability, the advantage of an easy, time-saving, and individually adjustable application during the operation.

Adult↗
PubMed2004

Ossicular reconstruction with titanium prosthesis.

OBJECTIVES: To evaluate the results when using titanium total ossicular replacement prosthesis (TORP) or partial ossicular replacement prosthesis (PORP) in chronic ear disease. STUDY DESIGN: Retrospective chart review was performed. METHODS: Sixty-eight ossicular procedures using a titanium TORP (n = 30) or PORP (n = 38) were performed at a tertiary referral center between December 1999 and June 2002. The ossiculoplasty was performed either alone or in combination with other chronic ear surgery. Cartilage grafts were used universally. Nineteen percent were primary operations, and 6% were planned second stages. The majority were revision procedures. Follow-up ranged from 3 months to 2.5 years. RESULTS: The prosthesis is easy to insert, well tolerated, and has a low extrusion rate. Average air-bone gap (ABG) improvement was 13 dB with closure of the ABG to within 20 dB in 57% of cases. Hearing results were better for primary versus revision cases for PORPs versus TORPs and for intact canal wall (ICW) procedures versus canal wall-down (CWD) procedures. CONCLUSION: Titanium is a satisfactory material for use in ossicular reconstruction because of its ease of insertion, tissue tolerance, and low rate of extrusion. Caution is advised when selecting candidates for this procedure during revision surgery, especially if the canal wall and stapes superstructure are absent.

Adult↗
PubMed1989

Titanium mesh and acrylic cranioplasty.

Since June 1985 100 cranioplasties have been carried out using titanium mesh and acrylic. There have been no complications and no infections. Titanium mesh is virtually radiolucent. Titanium is nonmagnetic and is the most biocompatible metal known.

Acrylic Resins↗
PubMed2001

Temporalis muscle resuspension using titanium miniplates and screws: technical note.

OBJECTIVE: To describe the technique for and results of using titanium miniplates and screws for resuspension of the temporalis muscle after osseous detachment during cranial procedures requiring exposure of and access to the frontotemporoparietal region. METHODS: Thirty-four patients, who were being treated with various cranial procedures, underwent resuspension of the dissected temporalis muscle, using 1.5-mm or 1.3-mm titanium plates and screws, after bone flap replacement. RESULTS: The temporalis muscle was successfully and securely resuspended in all cases, using the plates and screws. There were no infections, muscle tears, dislodgement, fractures, or temporal hollowing in any of the cases. In four cases that required re-exploration, the muscle was observed to be rigidly fixated and scarred to the bone. CONCLUSION: The use of titanium plates and screws is a safe, simple, successful alternative for reattachment of temporalis muscles for patients undergoing cranial procedures.

Adolescent↗