The purpose of this study was to compare the corrosion characteristics between implant fixture and two types of abutment screw; gold screw, titanium screw. The anodic polarization behavior, the galvanic corrosion behavior, and the crevice corrosion behavior of prepared samples were investigated using potentiostat and scanning electron microscope. The results were as follows : 1. Anodic polarization behavior of samples: The primary passivation potential of implant fixture was -420mV, implant abutment was -560mV, titanium screw was -370mV and gold screw was -230mV. All samples were shown to have a high corrosion potential and good formation of passive film. The critical passive current density of gold screw was higher than of other samples and the sample of gold screw showed a unstable passive film formation at passive region. 2. Galvanic corrosion behavior of samples: Contact current density between implant fixture and titanium screw showed 8.023x 10-5C/cm2. Contact current density between implant fixture and gold screw showed 5.142x 10-5C/cm2. 3. Crevice corrosion behavior of samples : The crevice corrosion resistance of sample using titanium screw was higher than that of sample using gold screw, and a severe corrosion morphologies were observed at the fixture-screw interface by the scanning electron microscope.
Corrosion* ; Titanium

No abstract available.
Hamartoma*

No abstract available.
Bacteremia* ; Staphylococcus aureus* ; Staphylococcus*

We measured poiyethylene wear radiographically in 85 cementless primary total hip arthroplasties by the modified technique of Livermore et al. All the patients were followed up for at least five years (mean, 6.31 years; range, 5 years-8 years 2 months). The mean extent of linear wear was 0.88mm (range, 0.0083-3.2839mm), and the mean rate of linear wear was 0.14mm/year(range, 0.00-0.47mm /year). The mean volumetric wear was 539.42mm (range, 5.11 2022.09mm), and the mean rate of volumetric wear was 87.69mm/year(range, 0.65-290.12mm/year). The polyethylene wear was correlated inversely with the patients age only, but was not influenced by weight or gender of the patients, Harris hip score, thickness of the polyethylene, the abduction angle of acetahular cup, or the duration of in situ implantation. Osteolysis developed in the femur of 34 hips(40%) and in the acetabulum of 11 hips(12.9%). Radiographic loosening was found in one case in the femur and none in the acetabul pm. The extent of polyethylene wear was significantly correlated with frequencies and sizes of the osteolytic lesion and was not directly associated with radiographic loosening of the prostheses. Calcar resorption was observed in 39 hips(45.9%) and was not associated with polyethylene wear. These results indicated that polyethylene wear of primary total hip arthroplasty should be considered one of major causes of osteolysis and has no direct relationship with prosthesis loosening. To reduce the extent of polyethylene wear, the material characteristics of polyethylene should be improved or new, durable, articulating materials should be researched.
Acetabulum ; Arthroplasty ; Arthroplasty, Replacement, Hip* ; Femur ; Hip ; Humans ; Osteolysis* ; Polyethylene* ; Prostheses and Implants ; Prosthesis Failure

No abstract available.
Stents*

No abstract available.
Pulmonary Atelectasis*

No abstract available.
Carcinoma, Endometrioid*

No abstract available.
Animals ; Linoleic Acid* ; Mice* ; Sarcoma 180* ; Sarcoma*

STATEMENT OF PROBLEM: Implant screw loosening has been remained problem in restorative practices. Surface treatment of screw plays a role of preventing screw from loosening in implant screw mechanism. PURPOSE: The purpose of this study was to investigate surface characteristics of TiN and ZrN film ion plated screw with titanium and gold alloy screw and to evaluate wear resistance, surface roughness, and film adhesion on screw surface using various instruments. MATERIAL AND METHODS: GoldTite screws and titanium screws provided by 3i (Implant Innovation, USA) and TorqTite screws or titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, korea) were selected. Ion plating which is much superior to other surface modification techniques was carried out for gold screws and titanium screws using Ti and Zr coating materials with nitrogen gas. Ion nitrided surface of each abutment screw was observed with field emission scanning electron microscopy(FE-SEM), micro-diamond scratch tester, vickers hardness tester, and surface roughness tester. RESULTS: 1) The surface of gold screw and GoldTite is more smooth than ones of other kinds of non coated screw. 2) The ZrN and TiN coated surface is the more smooth than ones of other kinds of screw. 3) The hardness of TiN and ZrN coated surface showed higher than that of non coated surface. 4) The TiN coated titanium screw and ZrN coated gold screw have a good wear resistance and adhesion on the surface. 5) The surface of ZrN coated screw showed low surface roughness compared with the surface of TiN coated screw. CONCLUSION: It is considered that the TiN and ZrN coated screw which would prevent a screw from loosening can be appilcable to implant system and confirmed that TiN and ZrN film act as lubricant on surface of screw due to decrease of friction for recycled tightening and loosening.
Alloys ; Dental Implants* ; Friction ; Hardness ; Hardness Tests ; Nitrogen ; Tin ; Titanium

Since the introduction of percutaneous mitral valvotomy(PMV) in 1984, PMV was an effecive alternative to surgical commissurotomy in selected patients with severe mitral stenosis. Also PMV was an excellent palliative strategy in such patients who were high risk for operative management or longterm anticoagulation was not feasible. We performed PMV in a patient with very tight mitral stenosis and severe pulmonary hypertension under the general anesthesia because the patient was anticipated to be uncooperative due to mental problem, who was diagnosed as schizophrenia 16 years ago. Robinol was used for premedication and i.v fentanyl was used for maintenance of anesthesia. Inoue balloon was introduced into the LV and gradual ballooning was performed with favorable results. Total anesthesia time and interval from internal jugular vein puncture to the completion of valvuloplasty were 1 hour 45 min and 40 minutes respectively. Hemodynamic variables were improved immediately after intervention and mitral valve area was increased from 0.5cm2 to 1.3cm2.
Anesthesia ; Anesthesia, General* ; Fentanyl ; Hemodynamics ; Humans ; Hypertension, Pulmonary ; Jugular Veins ; Mitral Valve ; Mitral Valve Stenosis* ; Premedication ; Punctures ; Schizophrenia*