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PubMed1998

Mechanical strength of fracture plates made of titanium for functionally stable mandibular reconstruction.

Plates for functionally stable mandibular reconstruction are successfully introduced with biocompatible titanium. While screws have been the subject of numerous investigations, only few results are available for the mechanical stability of plates. This contribution gives an overview about experimental possibilities to test plates in tensional, bending, and torsional strength as well as fatigue, and reports results about plates made of titanium and oxygen-alloyed titanium. The alloyed material is harder, stiffer and shows higher tensile strengths. In contrast to softer titanium, contouring procedures during implantation can lead to structural defects and an associated higher fracture risk.

Biomechanical Phenomena↗
PubMed2003

Bacterial adhesion on titanium nitride-coated and uncoated implants: an in vivo human study.

Titanium nitride (TiN) has been used in many fields as a surgical instrument coating that makes the surgical materials more resistant to wear and corrosion. The aim of the present study was an in vivo evaluation of the bacterial adhesion to TiN-coated (test) and uncoated (control) titanium implants. Six patients aged between 21 and 25 years and in excellent systemic health participated in the study. All of the participants gave their informed consent. The participants were selected on the basis of good periodontal health and no signs of mouth breathing. In each of the 6 participants, a removable acrylic device was adapted to the molar-premolar region of each quadrant of the jaws. One 4 x 13 mm titanium implant was glued to the buccal aspect of each device. The plasma spray covered 11.5 mm of the body of the implant, whereas the neck was machined titanium. Test implants were glued to the right devices and control implants were glued to the left devices. After 24 hours, the implants were removed from each device and processed for scanning electron microscopy for evaluation of the machined portion of the implant covered by bacteria. A total of 24 implants were used in this study, 12 test and 12 control. Surface characterization of the machined portion of the neck of the implant was performed on an additional 10 implants (5 test and 5 control). On test implants the implant surface covered by bacteria was significantly lower compared with that of control implants (P = .0001). The surface roughness was similar in both groups. TiN surfaces showed a significant reduction of the presence of bacteria, and this fact could probably be important in the decrease of the inflammation of the peri-implant soft tissues.

Adult↗
PubMed2006

Use of titanium mesh for staged localized alveolar ridge augmentation: clinical and histologic-histomorphometric evaluation.

The use of titanium mesh for localized alveolar ridge augmentation was evaluated by clinical, radiographic, laboratory, and histologic-histomorphometric evaluation. Seventeen patients participated in this study. All patients required localized alveolar ridge augmentation before placement of dental implants. An equal mixture of autogenous bone graft and inorganic bovine mineral (Bio-Oss) was used as a bone graft material. Autogenous bone graft was harvested intraorally. Titanium mesh was submerged for 8.47 months (SD 2.83). Impressions were taken intraorally before bone grafting, 6 months after bone grafting, and 6 months after implant placement. Impressions were used to measure the volume of alveolar ridge augmentation and provide linear laboratory measurements regarding the results of bone augmentation. Bone quality (type II-IV) was recorded during implant surgery. Standardized linear tomographs were taken before bone grafting and before implant placement. A biopsy was harvested with a trephine bur from the grafted area during implant surgery for histologic-histomorphometric evaluation. In all cases the grafted area had adequate bone volume and consistency for placement of dental implants. Early mesh exposure (2 weeks) was observed in 2 patients, and late exposure (>3 months) was observed in 4 patients. Volumetric laboratory measurements indicated 0.86 cc (SD 0.69) alveolar augmentation 1 month after bone grafting, 0.73 cc (SD 0.60) 6 months after bone grafting, and 0.71 cc (SD 0.57) 6 months after implant placement. This indicated 15.11% resorption 6 months after bone grafting, and no further resorption occurred after implant placement. Linear laboratory measurements indicated vertical augmentation of 2.94 mm (SD 0.86) 1 month after bone grafting, 2.59 mm (SD 0.91) 6 months after bone grafting, and 2.65 mm (SD 1.14) 6 months after implant placement. The corresponding measurements for labial-buccal augmentation were 4.47 mm (SD 1.55), 3.88 mm (SD 1.43), and 3.82 mm (SD 1.47). Radiographic evaluation indicated 2.56 mm (SD 1.32) vertical augmentation and 3.75 mm (SD 1.33) labial-buccal augmentation. Histomorphometric evaluation indicated 36.47% (SD 10.05) new bone formation, 49.18% (SD 6.92) connective tissue, and 14.35% (SD 5.85) residual Bio-Oss particles; 44.65% (SD 22.58) of the Bio-Oss surface was in tight contact with newly formed bone. The use of titanium mesh for localized alveolar ridge augmentation with a mixture of autogenous intraorally harvested bone graft and Bio-Oss offered adequate bone volume for placement of dental implants. Intraorally harvested autogenous bone graft mixed with Bio-Oss under a titanium mesh offered 36.47% new bone formation, and 15.11% resorption occurred 6 months after bone grafting.

Adolescent↗
PubMed2003

Performance of double acid-etched surface external hex titanium implants in relation to one- and two-stage surgical procedures.

BACKGROUND: The use of external hex titanium implants is widely accepted; however, in the past few years, they have been placed by using not only the traditional two-stage surgical protocol, but also the one-stage surgical protocol. The aim of the present study was to compare the success rates that can be obtained from two-stage surgeries (conventional protocol) and one-stage surgeries when double acid-etched surface external hex titanium implants are used. METHODS: A total of 654 double acid-etched surface external hex titanium implants were studied in 195 patients (109 females and 86 males) aged 18 to 79 (mean 49.20). These patients were followed-up both clinically and radiographically for 3 years. Among these implants, 338 were inserted by means of two-stage surgery and 316 were placed following the one-stage surgery protocol. RESULTS: The success rate of the whole sample of double acid-etched surface implants was 99.23%. The results showed a 99.05% success rate for one-stage surgeries and 99.40% rate for two-stage surgeries. Only three of the implants inserted by performing one-stage surgery and two of the implants placed using two-stage surgery failed before they were loaded. No implants were lost after the loading was completed. The bone level at 12 months was 0.58 mm for one-stage-placed implants and 0.54 mm for two-stage-placed implants. At 24 months the bone level was 0.77 mm and 0.68, respectively, and at 36 months 0.89 and 0.83. CONCLUSION: The similar and high success rates obtained in one- and two-stage surgeries using double acid-etched surface external hex titanium implants demonstrate that it is possible to choose the most convenient surgical procedure for each particular case without increasing the risk of failure.

Acid Etching, Dental↗
PubMed2005

Analysis of failed commercially pure titanium dental implants: a scanning electron microscopy and energy-dispersive spectrometer x-ray study.

BACKGROUND: The failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure. METHODS: Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant. RESULTS: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium. CONCLUSION: These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.

Biocompatible Materials↗
PubMed2006

Effect of cigarette smoke inhalation and estrogen deficiency on bone healing around titanium implants: a histometric study in rats.

BACKGROUND: It has been shown that cigarette smoke inhalation (CSI) and estrogen deficiency (OVX) may affect bone quality around titanium implants; however, their association has not been evaluated. Therefore, this study aimed to verify the effects of CSI associated with OVX on bone healing around titanium implants. METHODS: The tibia surface of 45 female Wistar rats was surgically exposed, and screw-shaped titanium implants were placed. The animals were randomly assigned to OVX (ovariectomized rats; n = 15), SHAM (sham-operated rats; n = 15), and CSI + OVX (4 months of intermittent cigarette smoke inhalation, starting 2 months before implant placement in ovariectomized rats; n = 15). The implants were placed at the time of OVX or SHAM surgery. After 60 days, the animals were sacrificed and undecalcified sections obtained. The percentages of mineralized tissue (bone density [BD]) in a 500-microm-wide zone lateral to the implant, bone filling (BF) within the limits of the threads, and bone-to-implant contact (BIC) were measured in cortical (zone A) and cancellous (zone B) bone. RESULTS: In zone A, the CSI + OVX group showed a significant difference regarding BIC and BD (P <0.05) compared to the other groups. In zone B, data analysis showed that the CSI + OVX group presented the lowest percentage of BD and BIC, followed by the OVX and SHAM groups, respectively (P <0.05). CONCLUSION: Within the limits of the present study, it can be concluded that cigarette smoke inhalation amplified the deleterious effects of estrogen deficiency, affecting both preexisting and newly formed bone in the cortical and cancellous bone around titanium implants.

Animals↗
PubMed1993

The differences in toxicity and release of bone-resorbing mediators induced by titanium and cobalt-chromium-alloy wear particles.

We investigated the relationship between the toxic effects of metal wear particles and their ability to stimulate the release of inflammatory mediators implicated in bone resorption. In vitro studies were carried out with use of rat peritoneal macrophages, which were exposed to either cobalt-chromium-alloy or titanium-aluminum-vanadium particles, milled from the metal components of hip prostheses. The particles were in the size-range of, and at concentrations similar to, those found in the tissues surrounding failed prostheses in humans. The titanium-aluminum-vanadium particles showed little toxicity even at high concentrations, while the cobalt-chromium particles were very toxic. The titanium-aluminum-vanadium particles induced significantly more release of prostaglandin E2 than did the cobalt-chromium particles, and this was true for a wide range of concentrations. Exposure to titanium-aluminum-vanadium increased the release of prostaglandin E2, interleukin-1, tumor necrosis factor, and interleukin-6. In contrast, exposure to cobalt-chromium particles was associated with a decreased release of prostaglandin E2 and interleukin-6, and it had little effect on the release of interleukin-1 and tumor necrosis factor.

Alloys↗
PubMed1994

The influence of a hydroxyapatite and tricalcium-phosphate coating on bone growth into titanium fiber-metal implants.

A study was done in rabbits to determine the effect of a hydroxyapatite and tricalcium-phosphate coating on bone growth into titanium fiber-metal implants. Titanium fiber rods with a solid titanium core were implanted bilaterally into the distal aspect of the femora of fifty-five New Zealand White rabbits. One rod was uncoated and the other rod was surface-coated with hydroxyapatite and tricalcium phosphate by the plasma-spray technique. Thirty-five rabbits were labeled sequentially with fluorochromes; killed at one, two, three, four, six, twelve, or twenty-four weeks after the operation; and studied histologically and histomorphometrically. The implants in the remaining twenty rabbits were subjected to pull-out testing to determine the shear strength at the implant-bone interface at three, six, twelve, and twenty-four weeks after the operation. Histomorphometry revealed significant effects of the hydroxyapatite and tricalcium-phosphate coating. When whole-group means (which included all time-points) were compared, it was found that 44 per cent of the perimeter of the hydroxyapatite and tricalcium-phosphate-coated implants was covered with bone compared with 12 per cent of the perimeter of the uncoated implants. The percentage of the internal surface of the implant that was covered with bone was also significantly higher in the hydroxyapatite and tricalcium-phosphate-coated implants: 27 per cent of the internal surface of the coated implants was covered compared with 8 per cent in the uncoated implants. The amount of bone in the pores of the implants was also higher in the hydroxyapatite and tricalcium-phosphate-coated implants: 12 per cent of the available pore space in the hydroxyapatite and tricalcium-phosphate-coated implants was filled with bone compared with 4 per cent in the uncoated implants. Scanning electron microscopy of the implants, done in backscatter mode, demonstrated apposition of new bone directly on the hydroxyapatite and tricalcium-phosphate coating, with variable degrees (amounts) of hydroxyapatite and tricalcium-phosphate resorption and new-bone replacement over time. Bone was never directly apposed to uncoated titanium fiber-metal. The pull-out strength of the hydroxyapatite and tricalcium-phosphate-coated implants was consistently greater than that of the uncoated implants, at all time-periods.

Animals↗
PubMed1999

Signaling pathways for tumor necrosis factor-alpha and interleukin-6 expression in human macrophages exposed to titanium-alloy particulate debris in vitro.

BACKGROUND: Loosening of the implant after total joint arthroplasty remains a serious problem. The activation of macrophages by wear debris from implants, mediated by the release of cytokines that elicit bone resorption, may lead to loosening. The purpose of the present study was to elucidate the mechanisms of macrophage activation by titanium particles from the components of implants and to identify the signaling pathways involved in particle-mediated release of cytokines. METHODS: Macrophages were isolated from mononuclear leukocytes obtained from healthy human donors and were exposed to titanium-alloy particles that had been obtained from periprosthetic membranes collected at revision total joint arthroplasties and then enzymatically prepared. The experimental protocols included examination of the effects of the inhibition of phagocytosis and the binding of antibodies to macrophage complement receptors on particle-induced macrophage activation. The release of the proinflammatory cytokines TNF-alpha (tumor necrosis factor-alpha) and IL-6 (interleukin-6) was used to assess macrophage activation. The signaling pathways involved in the induction of cytokine release were analyzed by identification of phosphorylated proteins with use of the Western blot technique and by translocation of the transcription factors nuclear factor-kappa B (NF-kappaB) and nuclear factor-interleukin-6 (NF-IL-6) into the nuclear protein fraction with use of electrophoretic mobility shift assays. The role of serine/threonine and tyrosine kinase pathways in the activation of nuclear factors and the release of cytokines was examined with use of selective pharmacological agents. RESULTS: Exposure of macrophages to titanium-alloy particles in vitro for forty-eight hours resulted in a fortyfold increase in the release of TNF-alpha and a sevenfold increase in the release of IL-6 (p<0.01). Phagocytosis of particles occurred in approximately 73 percent of the macrophages within one hour of exposure. Pretreatment of the macrophages with cytochalasin B reduced phagocytosis by 95 percent but did not reduce the release of TNF-alpha or IL-6. Thus, phagocytosis of particles was not necessary for induction of the release of TNF-alpha or IL-6 in the cultured macrophages. Ligation of the macrophage CD11b/CD18 receptors by integrin-specific antibodies also increased the release of TNF-alpha and IL-6. Antibodies to CD11b/ CD18 receptors (macrophage Mac-1 receptors) reduced phagocytosis of particles by 50 percent (p<0.05). (The CD11b/CD18 macrophage receptor is the macrophage receptor for the complement component CR3bi. The CD11b/CD18 macrophage receptor can also bind to ICAM-1 and ICAM-2. CD is the abbreviation for cluster of differentiation, and ICAM is the abbreviation for intercellular adhesion molecule.) Inhibition of phagocytosis was not accompanied by a decrease in the release of TNF-alpha and IL-6. Blocking RNA synthesis with actinomycin D or preventing protein synthesis with cycloheximide abolished or decreased particle-induced release of TNF-alpha and IL-6 from the macrophages. Macrophage release of TNF-alpha and IL-6 in response to particles coincided with increased tyrosine phosphorylation and mitogen-activated protein kinase activation. Inhibition of tyrosine and serine/threonine kinase activity decreased the particle-induced release of cytokines. Exposure of macrophages to either titanium-alloy particles or to antibodies to the receptor proteins CD11b and CD18 for thirty minutes activated the transcription factors NF-kappaB and NF-IL-6. Inhibition of particle phagocytosis did not block activation of the transcription factors. However, inhibition of tyrosine and serine/threonine kinase activity decreased the activation of NF-kappaB and NF-IL-6. CONCLUSIONS: These data suggest that particle induced macrophage release of TNF-alpha and IL-6 does not require phagocytosis but is dependent on tyrosine and serine/threonine kinase activity culminating in activation of

Alloys↗
PubMed2003

Comparison of porous-coated titanium femoral stems with and without hydroxyapatite coating.

BACKGROUND: The purpose of this prospective, randomized study was to evaluate the clinical and radiographic results associated with proximally porous-coated titanium stems that were identical in geometry but differed with regard to proximal surface treatment (with or without hydroxyapatite coating). METHODS: A prospective, randomized study was performed to evaluate fifty patients (100 hips) who had undergone sequential bilateral primary total hip replacement. A proximally porous-coated titanium stem with hydroxyapatite coating was implanted on one side and a proximally porous-coated titanium stem without hydroxyapatite coating was implanted on the other side during the same operative setting in all fifty patients. A cementless acetabular component made of titanium was used in all hips. There were thirty-six men and fourteen women; the mean age at the time of the operation was 45.3 years. The mean duration of follow-up was 6.6 years. Clinical and radiographic evaluations were performed preoperatively; at six weeks; at three, six, and twelve months; and yearly thereafter. RESULTS: The Harris hip scores in the hydroxyapatite-coated group (mean, 94 points) and non-hydroxyapatite-coated group (mean, 92 points) were similar at the final follow-up examination. The prevalence of transient pain in the thigh was 4% in each group. No acetabular or femoral component demonstrated aseptic loosening. Bone-remodeling patterns, including calcar atrophy, were similar in the two groups. No acetabular or femoral osteolysis was seen. CONCLUSIONS: At a mean of 6.6 years postoperatively, the clinical and radiographic results associated with proximally porous-coated femoral prostheses with identical geometries that differed only with regard to the presence or absence of hydroxyapatite coating were similar.

Adult↗
PubMed1999

Osseointegration around titanium screws placed into the areas between guided bone augmented sites compared with osseointegration around guided bone graft augmented sites in rabbit tibia.

The aim of this study was to compare the degree of osseointegration around titanium screws placed into the areas between guided bone augmented sites and guided bone graft augmented sites in 8 Japanese white rabbit tibia. The skin and periosteum were incised and lifted to expose the inner surfaces of both tibia. Eight rabbits were divided into 2 groups: 1) a guided bone augmentation (GBA) group of 2 rabbits, and 2) a guided bone graft augmentation (GBCA) group of 6 rabbits. In the GBA group, the bone marrow was penetrated several times in both tibial bones. Three titanium screws were inserted into the bone so that the top of each screw was 3 mm above the bone surface and covered with an expanded polytetrafluoroethylene membrane (ePTFE). In the GBGA group autogenous cortical bone (10 mm x 10 mm x 1 mm) was taken from the left tibia and grafted on the inner surface of the right tibial bone, titanium screws being similarly inserted. The surgical site was covered by ePTFE. After healing for 2 months, the animals were euthanatized, and the experimental area was prepared for histological investigation. New bone had formed on the surgical sites in the GBA group and grafted bone had survived in the GBGA group, with no sign of infection or membrane exposure. The degree of osseointegration around the screw was 67.6 +/- 11.2% (mean +/- SD) in the GBA group and 78.8 +/- 11.9% in the GBGA group. There was no significant difference between the groups (p = 0.29). The ratio of mineralized bone to bone marrow was 45.7 +/- 6.2% in the GBA group and 64.4 +/- 4.4% in the GBGA group. There was a significant difference between the groups (p < 0.05). Although there was no significant difference for osseointegration around the screw placed into the GBA and GBGA sites, the quality of newly generated bone or grafted bone was quite different. Therefore, we suggest that predictable bone augmentation beyond the bone surface can be achieved by either the GBA or the GBGA procedure with ePTFE. However, it was difficult to conclude which procedure was superior with respect to the osseointegration around the titanium screw.

Animals↗
PubMed2000

A case of localized ridge augmentation from using a titanium membrane: a pilot study.

The aim of this investigation was to histologically compare the effects of new titanium membranes with those of proven expanded polytetrafluoroethylene (ePTFE) membranes on alveolar ridge augmentation. The study was carried out using a canine mandible where the right and left premolar teeth were previously extracted. At the second month of healing following extraction, a total of seven similar defects were created on both sides of the mandible. Three defects received the titanium membrane, one of which was in the right side of the mandible. Two defects, one on each side, received the ePTFE membrane. The remaining two defects, both on the right side, served as control. Fixation and stabilization of the membranes were accomplished by using the Frios Augmentation System. After three months of healing, the animal was sacrificed, block sections were taken and processed for histological examination according to the cutting and grinding technique. The results revealed that the ePTFE and titanium-treated defects, and the controls, showed complete bone fill with the exception that there was a more pronounced and thicker connective tissue formation in titanium-treated sites as compared to the ePTFE treated and control sites.

Alveolar Ridge Augmentation↗
PubMed2001

Titanium casting: the surface reaction layer of castings obtained using ultra-low-temperature molds.

To examine whether the surface reaction layer of titanium castings can be reduced by lowering the mold temperature during casting, we cast titanium at three mold temperatures, including an ultra-low temperature produced by cooling the mold with liquid nitrogen, then measured the tensile strength and elongation of the castings. The titanium was cast using a centrifugal casting machine, and the molds were incinerated according to the manufacturers' instructions. Castings were then made with the molds at 200 degrees C, 600 degrees C, and an ultra-low temperature (-196 degrees C). The castability of titanium cast in the mold at the ultra-low temperature was good. The Vickers hardness near the surface layer of castings decreased as the mold temperature decreased.

Cold Temperature↗
PubMed1988

Laser welding of titanium in dentistry.

Unalloyed titanium of the quality used for osseointegrated implants by the method of Brånemark is also sometimes used for the metallic part of the prosthetic superstructure placed on the fixtures and for crowns and bridges of conventional type. Forty bars of titanium, 8 of ASTM B 348 grade-1 quality and 32 of ASTM B 348 grade-2 quality, were laser-welded, using dissimilar laser joint variables. Tensile strength, 0.2% proof stress, and percentage elongation of the welded bars were measured and compared with the corresponding values for the titanium bars as delivered and with those of brazed type-3 gold alloy bars of similar dimensions. The type of fracture was evaluated from fractographs. The results showed that the use of certain defined laser joint variables during welding produced values for the mechanical properties studied which were more favorable than those obtained from the brazed gold bars. The fracture of the titanium specimens was ductile, with dimples occurring at the fracture surfaces.

Dental Alloys↗
PubMed1994

Imaging after titanium cranioplasty.

Titanium cranioplasty has been used in our unit for reconstruction of cranial defects following trauma, tumour resection and bone loss due to postcraniotomy infection. It has previously been assumed that imaging to assess recurrence of disease progression after cranioplasty would be severely compromised in the presence of metallic material. Titanium is a non-ferrous metal of low atomic number, which is relatively radiolucent and allows exceptionally clear images to be obtained without significant degradation of image quality, on CT and magnetic resonance (MR) imaging. Cases are presented that demonstrate the use of CT contrast cisternography and MR imaging after titanium cranioplasty. On the basis of its strength, biocompatibility and excellent handling characteristics, allied to its suitability for all post-operative imaging techniques, we conclude that titanium plate is the material of choice for cranioplasty.

Brain Diseases↗
PubMed1991

Backscatter radiation at tissue-titanium interfaces. Analyses of biological effects from 60Co and protons.

It has been claimed that implanted metals can cause backscatter radiation in radiation therapy with a dose enhancement at the bone-metal and tissue-metal interfaces on the beam entrance side. Theoretical calculations and experimental measurements with ionization chambers have indicated that such effects might be significant. Titanium implants are increasingly used in oral and maxillo-facial surgery for reconstruction purposes. A more detailed knowledge of backscatter-induced effects is therefore desired when head and neck cancers in patients with implants are treated with radiotherapy. We have made comparisons of cell survival after irradiation of two types of cultured cells grown directly on titanium metal and on plastic control supports. The cell cultures were irradiated with either 60Co photons or range modulated protons. No significant differences in the colony-forming capacity were found between the irradiated cells grown on titanium and those grown on plastic control supports. This was the case for both radiation types and the results were also observed to be dose-independent. The only observed phenomena were that the two cell-lines differed in radiosensitivity and that protons gave higher biological effects than gamma radiation. The results show that there were no significant changes in cell survival at the interface between the tissue equivalent medium and titanium support indicating that a dose increase induced by backscatter radiation, which possibly could demolish the osseointegration or induce osteoradionecrosis, are minimal when high energy photons or range modulated protons are applied.

Animals↗
PubMed2002

Prospective controlled study of rectangular titanium cage fusion compared with iliac crest autograft fusion in anterior cervical discectomy.

OBJECT: The complications of autogenous bone grafting compel spine surgeons to seek alternative methods for cervical spinal fusion. This prospective study was conducted to evaluate the safety and efficacy of using rectangular titanium cage fusion compared with the widely performed iliac crest autograft fusion. METHODS: A total of 36 patients with cervical disc disease in whom an anterior approach was indicated for discectomy were included in this prospective controlled study. The first 18 consecutive patients received iliac crest autograft; the next 18 consecutive patients received rectangular titanium cages. The intergroup demographic and clinical data were comparable. All patients attended follow up for 1 year. According to Odom criteria, 15 (83%) of 18 patients in both groups experienced good to excellent functional recovery. According to the Patient Satisfaction Index, 17 (94%) of 18 patients in both groups were satisfied. The evaluation of neck pain and arm pain did not indicate statistically significant differences between either group. Fusion was present after 1 year in 16 (89%) of 18 patients who received iliac crest autografts and in 15 (83%) of 18 patients who received rectangular titanium cages. In the autograft group, a pseudarthrosis was present in one patient and marked hip pain was observed in three patients. In the cage group, there was one case of temporary vocal cord paresis but no implant-related complications. CONCLUSIONS: The authors conclude that the use of titanium cages in anterior cervical discectomy constitutes a safe and efficient alternative to iliac crest bone autograft.

Adult↗
PubMed1999

Biodegradable semirigid plate and miniscrew fixation compared with rigid titanium fixation in experimental calvarial osteotomy.

OBJECT: To determine the biocompatibility and suitability of resorbable plates and miniscrews, consolidation of symmetrical, bilateral frontal bone craniotomies that had been closed using various methods was studied in 20 growing lambs. METHODS: Bone fixation with a flexible, punched polylactide plate and four slowly degradable, self-reinforced poly-levolactide (SR-PLLA) or rapidly degradable, self-reinforced polyglycolide (SR-PGA) miniscrews (10 animals in each group) was compared intraindividually with rigid fixation by using a titanium miniplate and four miniscrews. Plain x-ray films, magnetic resonance images, histological studies, and histomorphometric studies were obtained at 4 to 104 weeks. CONCLUSIONS: No dislocation, instability, clinical foreign body reactions, infections, or loss of fixation were observed. Bone consolidation of the 2.35-mm-wide craniotomy lines was incomplete; connective tissue-filled defects through the bone were observed in 13 of 28 lines at 26 to 52 weeks. Statistical analyses based on histomorphometric studies showed no difference in consolidation with SR-PLLA miniscrew and titanium plate/screw fixation or between the two resorbable fixation methods. Fixation with rapidly degradable SR-PGA miniscrews resulted in less effective consolidation than on the contralateral titanium-treated side (p<0.05), but the bone segment was thicker (p<0.005). The SR-PGA miniscrews had disappeared by 6 weeks, the polyactide plate by 104 weeks, and the SR-PLLA miniscrews had been mostly resorbed at 104 weeks. Passive translocation of the titanium plates and screws into the bone tissue was seen at 52 and 104 weeks. In rapidly growing lamb frontal bone, comparable consolidation results, without complications, can be achieved with semi-rigid resorbable fixation compared with rigid metallic fixation.

Absorbable Implants↗