Dental restorative materials must have the physical properties to withstand wear and corrosion. Base metal alloys possess better mechanical properties and lower price than the gold alloys. For these reason such alloys have largely replaced the precious metal alloys. One aspect to consider is the release of metal substances to oral environment. The release of elements from dental alloys is a continuing concern because the elements may have the potentially harmful biological effects on local tissue. The purpose of this study was to minimize metal release on the nonprecious metal surfaces by ion bea assisted deposition(IBAD) of titanium nitride (TiN). Ni-Cr-Be alloys with and without TiN coatings were secured in an wear test machine opposing ruby ball to determine their relative resistance to wear with 100m, 200m, 300m and 400m sliding distance. And the corrosion behavior of the Ni-Cr-Be alloys with and without TiN coating and 3 dental noble alloys have been studied. Potentiodynamic curves were used to analyse the corrosion characteristics of the alloys. The measurement of the released Ni and Ci ions was conducted by analysis of the electrolyte solution with atomic absorption spectroscopy. The results were as follows : 1. The critical sliding distance that wore down TiN coating of 2.5micrometer thickness in this study condition was 300m. 2. Ion beam assisted deposition of TiN showed a good surface modification with respect to the properties of wear and corrosion resistance. 3. X-ray diffraction showed that the strongest peak of TiN(111) in the coatings. 4. The release of Ni and Cr ions from alloys measured by means of atomic absorption spectroscopy was reduced by ion beam assisted deposition of TiN.
Absorption ; Alloys* ; Corrosion ; Dental Alloys ; Gold Alloys ; Ions ; Spectrum Analysis ; Tin* ; Titanium ; X-Ray Diffraction

No abstract available.
Cerebral Hemorrhage* ; Mucormycosis*

The metal ceramic crown is currently the most popular complete veneer restoration in dentistry, but in many cases, the metal cervical collar at the facial margin is unesthetic and unacceptable. Facial porcelain margin has been used in place of it. But this dose not solve the problems, such as dark gingival discoloration and cervical opaque reflection of porcelain veneer. Recently, metal copings which were designed to terminate its labio-cervical end on the axial walls coronal to the shoulder have been clinically used to solve the esthetic problem of metal ceramic crown. But in this design, porcelain veneer of labio-cervical area which is not supported by metal may not be able to resist the stress during cementation and mastication. The purpose of this study was to evaluate fracture strength and fractured appearance of crowns according to different coping designs. A resin maxillary left central incisor analogue was prepared for a metal ceramic crown, and metal dies were made with duplication mold. Metal copings were made and assigned to one of four groups based on facial framework designs: group 1, coping with 0.5mm metal collar; group 2, metal extended to the shoulder; group 3, metal extended to 1 mm coronal to the shoulder; group 4, metal extended to 2mm coronal to the shoulder. Copings and crowns were adjusted to be same size and thickness, and cemented to metal dies with zinc phosphate cement by finger pressure. Fracture strength was measured with Instron Universal Testing Machine. Metaldies were anchored in Three-way-vice at 3mm below finish line and at 130degree inclined to the lone axis of the crown. Load was directed lingually at 2mm below midincisal edge. Load value at initial crack and at catastrophic fracture was recorded. The results obtained were as follows: 1. Fracture strength values at initial crack were higher in groups 1, 2 than in groups 3, 4 but this difference was not statistically significant(P<0.05). 2. Conventional metal collared crown had greater catastrophic fracture strength than any other collarless crowns. 3. The greater the labial metal coping reduction, the lower the catastrophic fracture strength of crowns but when more than 1mm of labial metal reduction was done, the difference in strengths was not statistically significant(p<0.05). 4. The strongest collarless coping design was group 2.
Axis, Cervical Vertebra ; Cementation ; Ceramics* ; Crowns* ; Dental Porcelain ; Dentistry ; Fingers ; Fungi ; Incisor ; Mastication ; Shoulder ; Zinc Phosphate Cement

20-40% of cases of acute transverse myelitis are attributed to viral infections, although the specific viral etiology is only rarely identified. We have studied one patient with transverse myelitis in association with acute hepatitis B virus infection. Hepatitis virus should be considered as rare cause of transverse myelitis.
Hepatitis B virus* ; Hepatitis B* ; Hepatitis Viruses ; Hepatitis* ; Humans ; Myelitis, Transverse*

Gastrointestinal (GI) stent has been developed for palliation of obstructive symptoms in various diseases causing obstruction of GI tract. Self-expanding metal stent (SEMS) has replaced old type of plastic stent, and endoscopic insertion of stent has replaced fluoroscopy-guided insertion. Nowadays, newly-designed SEMSs have been developed for prevention of complications such as stent migration and re-obstruction, and indications of stent recently have been widened into benign conditions as well as malignant obstruction. In this review, the types, method of insertion, indications and clinical outcomes of stent in the upper GI tract would be discussed.
Gastrointestinal Tract ; Plastics ; Stents ; Upper Gastrointestinal Tract

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed drugs in the world. NSAID-induced lower gastrointestinal (GI) complications are increasing while upper GI complications are decreasing. Lower GI events accounted for 40% of all serious GI events in patients on NSAIDs. Capsule endoscopy and device assisted enteroscopy are available for detection of small intestinal lesions. Capsule endoscopy studies have demonstrated that NSAIDs use in healthy volunteers raised the incidence (55% to 75%) of intestinal damage. It appears that selective cyclooxygenase-2 inhibitors (coxibs) improved upper and lower GI safety based on results of clinical trials. Selective coxibs are still capable of triggering GI adverse events and cardiovascular toxicity issues were the main focus of concerns. Unfortunately, definite strategies are not available to prevent or heal NSAID-induced intestinal injuries. Thus, there is still a strong clinical need for effective drugs with improved safety profiles than the existing NSAIDs.
Anti-Inflammatory Agents, Non-Steroidal ; Capsule Endoscopy ; Cyclooxygenase 2 Inhibitors ; Humans ; Incidence ; Lower Gastrointestinal Tract

Although the global prevalence of peptic ulcer disease (PUD) is decreasing, PUD is still one of the most common upper gastrointestinal diseases in the world due to Helicobacter pylori infection and increased use of non-steroidal anti-inflammatory drugs. In Korea, the prevalence of H. pylori infection is also declining, but it is still the major cause of PUD. The outcomes of H. pylori infection are caused by imbalances between bacterial virulence factors, host factors, and environmental influences. In this review, we describe the prevalence trends of H. pylori infection in Korea, the mechanism of H. pylori infection-related PUD, and treatment strategies.
Epidemiology ; Gastrointestinal Diseases ; Helicobacter pylori* ; Helicobacter* ; Korea ; Peptic Ulcer* ; Prevalence ; Virulence Factors

Stent implantation in the upper gastrointestinal (UGI) tract is now widely accepted for achieving palliative symptom relief of patients who have malignant UGI obstruction and causative symptoms such as nausea, vomiting, malnutrition and acid reflux. With the increased technical progress and clinical experiences, it has become possible to perform this procedure with more safety and convenience. However, clinicians should also focus on the post-procedural management because complications such as stent migration or in-stent tumor growth could occur. On the other hand, temporary stent insertion is an effective treatment option for benign diseases such as pyloric strictures due to benign peptic ulcer, esophageal perforation or leakage on the anastomosis site. In this review, several issues about stent implantation in the UGI tract, such as the main indications, the current status and the expected applications in other fields in the near future, are briefly discussed
Constriction, Pathologic ; Esophageal Perforation ; Hand ; Humans ; Malnutrition ; Nausea ; Peptic Ulcer ; Stents ; Vomiting

The authors performed prospectively the transcranial Doppler monitoring of middle cerebral arteries in 37 patients with ruptured cerebral aneurysm. The entry criteria for the study were confined to the patients who had clinical Grades of 1, 2, or 3, and were operated within 4 days after bleeding. There were several sonographic risk factors of developing delayed ischemic deficits; 1) An early steep increase of flow velocity exceeding 120 cm/sec. 2) An increase of maximum flow velocity more than 140 cm/sec. 3) The flow velocity increasing simultaneously with the onset of delayed ischemic deficit in which case preventive treatment was impossible. 4) Prolonged elevation of flow velocity for more than 7 days despite of aggressive treatment. It seemed to be mandatory to start preventive and aggressive treatment for the asymptomatic patients who showed higher flow velocity than 140 cm/sec. Transcranial Doppler sonography has another potential on deciding the timing of surgery.
Hemorrhage ; Humans ; Intracranial Aneurysm* ; Middle Cerebral Artery ; Prospective Studies ; Risk Factors ; Ultrasonography ; Ultrasonography, Doppler, Transcranial

BACKGROUND/AIMS: The purposes of this study were to investigate various environmental factors for colon polyps and to analyze locoregional clinical characteristics of colon polyps in Gyeongju and Pohang area. METHODS: From October 2005 to September 2006, patients who underwent colonoscopy were analyzed based on their ages, genders, body mass indices (BMI), dietary habits, smoking behaviors, accompaying diseases, and medications as risk factors for the occurrence of colon polyps. Then clinical manifestations, gross appearances and pathologic findings of polyps were investigated. RESULTS: Among 253 patients enrolled, a total of 296 colon polyps were found in 108 patients. The incidence of colon polyps in more than 50-year old patients was 3.2-fold greater compared to less than 50-year old patients. Smoking habits were also significantly associated with the occurence of colon polyps. Among adenomatous polyps, tubulovillous type and moderate to severe dysplasia were frequently observed as the size increased, yet the location of polyps was not significantly associated. CONCLUSIONS: Older age and smoking habit increase the risk of colon polyps. Rectal polyps have less chance to be adenomatous type. The larger the polyp grows, the more likely it to be tubulovillous and dysplastic.
Adenomatous Polyps/pathology ; Adult ; Aged ; Aged, 80 and over ; Colonic Polyps/*diagnosis/epidemiology/pathology ; Colorectal Neoplasms/*diagnosis/epidemiology/pathology ; Female ; Humans ; Korea ; Male ; Middle Aged ; Multivariate Analysis ; Odds Ratio ; Questionnaires ; Risk Factors ; Rural Population