The purpose of this study was to analyse the center of resistance of the maxillary first molar using the 3-dimension finite element method. An extracted maxillary first molar of normal shape and average root length was selected and sectioned every 1.5mm parallel to the cementoenamel junction. Each section was traced and digitized to construct 3-D finite element model of the maxillary first molar. After a certain magnitude of counterbalancing moment(M) was applied to the tooth, a varying single force(F) of distomesial direction was applied to a certain point of the tooth until the tooth was translated. The force producing translation(Ft) was substituted to the equation deltad = M/Ft to calculate the center of resistance of the maxillary first molar. And reducing the alveolar bone level 1.68mm, and 3.36mm below to the cementoenamel junction, the tooth movement was analysed to see the effect of reducing the alveolar bone level to the location of the center of resistance. The results were as follows; 1. The center of resistance of the maxillary first molar was 3.72mm apical, 1.10mm buccal, and 0.71mm mesial to the geometric center of the horizontally sectioned surface at the cementoenamel junction. This point was 0.36mm apical, 1.20mm buccal, and 0.71mm mesial to the trifurcation point, indicating that it was not on the tooth root. 2. As the alveolar bone level was reduced, the center of resistance of the maxillary first molar was moved to the apical direction.
Finite Element Analysis* ; Molar* ; Tooth ; Tooth Cervix ; Tooth Movement ; Tooth Root

Forty five cases of adult tibial shaft fractures were treated with flexible intramedullary nails under image intensifier at the department of orthopaedic surgery, Capital Armed Forces General Hospital during between April 1986 to July 1988. The results were summarized as follows: 1. 45 cases were all male, the average age was 24.3 years and the most common cause of fractures was sports injury(20 cases) and the second most common cause was traffic accident(18 cases). 2. 11 cases out of 45 cases were open fracture and 34 cases were closed fracture. Eight cases of open fraeture were grade I and three cases were grade II. Twenty eight cases were comminuted fracture. The most common level of the fracture was middle third of the tibial shaft. 3. Average interval from injury to Ender nailing was 13.5 days and the mean duration of permission to full weight bearing was 9.2 weeks. 4. Out of 2 cases of delayed union, the average time of clinical bone union was 9.7 weeks and that of roentgenological bone union was 14 weeks. 5. 11 cases of complication were noted among the 45 cases of tibial shaft fracture which were treated by PGP nailing such as angulation, rotation, ankle joint stiffness, delayed union, shortening, and soft tissue infection. 6. PGP nailing is considered to be a valuable method in treating tibial shaft fracture because of their relative ease of nailing, allowing early weight bearing and decreased complication.
Adult ; Ankle Joint ; Arm ; Fractures, Closed ; Fractures, Comminuted ; Fractures, Open ; Hospitals, General ; Humans ; Male ; Methods ; Soft Tissue Infections ; Sports ; Tibial Fractures ; Weight-Bearing

Dislocation of the clavicle at its sternal end is relatively rare, as compared with acromioclavicular dislocation. Among them, the posterior dislocation of the sternoclavicular joint was extremely rare. So, not more than fifty cases had been reported in the literature. Of these three main typesanterior, superior, and posterior-the anterior one is by far the most common. Most authors have stressed the difficulty in confirming the diagnosis with routine radiographs. We experienced a case of traumatic posterior dislocation of the sternoclavicular joint treated successfully by manipulative reduction. So, we report it with review of literature.
Clavicle ; Diagnosis ; Dislocations ; Sternoclavicular Joint

There are some controversies on the mechanism of the lumbar disc degeneration and disc prolapse. But,it is clear that many factors are related to the disc degeneration. Configurations of the lower lumbar and lumbosacral spine have long been proposed as one of the important factors of disc degeneration in these areas. To look for the configurational risk factors and the probability of disc degeneration by the combinations of these factors, we analyzed simple radiographs and MRI of 73 patients who complaints of low back pain and are between 20 years and 39 years of age. We performed chi-square test and multivariate logistic regression analysis: L4-5 disc degeneration and L5-Sl disc degeneration as dependent variables and lumbar lordosis, sacral inclination, height of intercrest line, transitional vertebra and facet joint asymmetry as independent variables. We could not find any of these variables significantly related to the L4-5 intervertebral disc degeneration. For L5-S1 disc degeneration, only the presence of transitional vertebra was signicantly related. When there is no transitional vertebra, the probability of disc degeneration is 9 times(8.889) as large as that of presence of transitional vertebra. The probability of L4-5 disc degeneration without the degeneration of L5-S1 is 3 times as large as that of degeneration of both of L4-5 and L5-S1 disc in case of the presence of transitional vertebra.
Animals ; Humans ; Intervertebral Disc Degeneration* ; Logistic Models ; Lordosis ; Low Back Pain ; Magnetic Resonance Imaging ; Prolapse ; Risk Factors ; Spine* ; Zygapophyseal Joint

BACKGROUND: We aimed to determine the major contributing component of metabolic syndrome (MetS) that results in an elevated small dense LDL cholesterol (sdLDL-C) concentration and sdLDL-C/LDL-C ratio. METHODS: Four hundred and forty-seven subjects (225 men; 222 women) with MetS were randomly selected from the Korean Metabolic Syndrome Research Initiatives-Seoul cohort study. Age- and sex-matched healthy controls (181 men; 179 women) were also randomly selected from the same cohort. RESULTS: A comparison of the median values of the sdLDL-C concentration between subgroups, divided according to whether subjects met or did not meet the criteria for each MetS component in patients with MetS, revealed a significant difference in the sdLDL-C concentration only between subgroups divided according to whether subjects met or did not meet the triglyceride (TG) criteria (P<0.05 for each gender). The TG level showed a good correlation with sdLDL-C concentration (correlation coefficients [r]=0.543 for men; 0.653 for women) and the sdLDL-C/LDL-C ratio (r=0.789 for men; 0.745 for women). Multiple linear regression analyses conducted for the MetS group concordantly identified TG as one of the most significant contributors to sdLDL-C concentration (beta=0.1747+/-0.0105, P<0.0001) and the sdLDL-C/LDL-C ratio (beta=6.9518+/-0.3011, P<0.0001). CONCLUSIONS: Among five MetS components, only the abnormal TG level was a differentiating factor for sdLDL-C concentration and sdLDL-C/LDL-C ratio. These results were reproducible in both genders, with or without MetS.
Adult ; Case-Control Studies ; Cholesterol, LDL/*blood ; Cohort Studies ; Female ; Humans ; Hypertriglyceridemia/*complications/diagnosis ; Linear Models ; Male ; Metabolic Syndrome X/*complications/diagnosis ; Middle Aged ; Risk Factors ; Triglycerides/blood

PURPOSE: In this study, patients in whom two computed tomography (CT) scans had been obtained within 24 hours of injury were analyzed to determine the incidence, risk factors and clinical significance of a progressive intracerebral hematoma (PIH). METHODS: Participants were 182 patients with a traumatic intracerebral hematoma and contusion who underwent a repeat CT scan within 24 hours of injury. Univarite and multivariate statistics were used to define growth (volume increase) and to examine the relationship between the risk factors and hemorrhage expansion. RESULTS: Fifty-four percent of the patients experienced progression in the size of the lesion in the initial 24 hours postinjury. A PIH was independently associated with worsened Glasgow coma scale (GCS) score (2.99, 1.04~8.60), the presence of subarachnoid hemorrhage (6.29, 2.48~16.00), the presence of a subdural hematoma (6.18, 2.13~17.98), the presence of an epidural hematoma (5.73, 1.18~27.76), and the presence of a basal cistern effacement (10.93, 1.19~99.57). CONCLUSION: For patients undergoing scanning within 2 hours of injury, the rate of PIH approaches 61%. Early repeated CT scanning is indicated in patients with a nonsurgically-treated hemorrhage revealed on the first CT scan. Worsened GCS score, significant hematoma growth and effacement of the basal cisterns on the initial CT scan are powerful predictors of which patients will require surgery. These findings should be important factors in understanding and managing of PIH.
Contusions ; Craniocerebral Trauma ; Glasgow Coma Scale ; Head ; Hematoma ; Hematoma, Subdural ; Hemorrhage ; Humans ; Incidence ; Risk Factors ; Subarachnoid Hemorrhage

No abstract available.
Hypercholesterolemia* ; Lipoprotein-X* ; Lipoproteins*

Sodium and potassium intake was assessed on the basis of its respective excretion levels in 24 hr urine samples. However, owing to the inconvenience of collection, we evaluated random spot urine for alternative sodium and potassium excretion markers. We included 250 patients who submitted 24 hr- and spot urine for clinical tests. However, 22 patients who showed 24 hr urine creatinine excretion levels <500 mg/day were excluded, because these samples possibly resulted from incomplete urine collection. Moreover, 24 patients were excluded because of their use of diuretics during the urine collection period. We observed significant correlations between 24 hr urine sodium excretion and both the sodium/creatinine (r=0.34, P<0.0001) and the sodium/specific gravity unit (SGU) ratios (r=0.19, P=0.007) in random urine samples. Similarly, 24 hr urine potassium excretion and both the spot urine potassium/creatinine (r=0.47, P<0.0001) and potassium/SGU ratios (r=0.28, P<0.0001) were significantly correlated. Although the estimated sodium/creatinine and potassium/creatinine ratios showed a significant correlation with 24 hr urine sodium and potassium excretion, respectively, further studies are required to develop a spot urine test for individualized monitoring of sodium and potassium excretion.
Biomarkers/urine ; Creatinine/*urine ; Humans ; Hypertension/pathology/urine ; Potassium/*urine ; Sodium/*urine ; Urinalysis ; Urine Specimen Collection

No abstract available.
Pelvic Bones*

Recent reports indicate that shorter etching times than 60 seconds can be adopted without affecting the bond strength and clinical disadvantages. The purpose of this in vitro study was to compare the shear bone strength and to measure depth of etch at different etching time length. One hundred and eight extracted bovine lower central incisors were embedded each in a tooth cup with cold-cure acrylic resin, The facial surfaces of the teeth were ground wet with 600-, 800-, 1000-, and 1200-grit Sic papers, and finally polished with a water slurry of extrafine silicon carbide powder, washed with tap water, and dried with hot air. Nine groups of nine prepared teeth were etched with a commercial(38% phosphoric acid solution) for 0, 5, 10, 15, 20, 30, 60, 90, and 120 seconds, respectively, rinsed with tap water, and dried with hot air. One conditioned teeth from every group was selected randomly for the scanning electron microscopic examination, and the remaining eight teeth of the groups were used for measuring the push shear bond strength after bonding brackets and immensing them in the 36.5degrees C water for 24 hours. Another nine groups of three teeth were used for measuring the depth of etch and surface roughness with a surface profilometer. after pieces of adhesive tape of 3mm inner diameter positioned on the ground enamel surfaces, and etched with the above mentioned. The data obtained form the above experiments were analysed statistically with one way ANOVA and Dunkan's multiple range test with the 95% confidence level. The results and conclusion of the study were as follows; 1. The results of shear bond strength for the given experimental etching times were not statistically different, but showed the tendency of decreasing shear bone strength after over 60 seconds etching times. 2. On the scanning election microscopic examination, it was observed that the morphological patterns of etched enamel surface for 5 to 20 seconds were similar and consitent, and those for 30 to 120 seconds showed increasing over-etched patterns depending on the length of etching times. 3. The depth of etch was increased almost proportionally by the length of etching times, but it was not associated with the shear bond strength. 4. The surface roughness increased depending on the length of etching times, but it was not associated with the shear bond strength. 5. This experiment indicated that proper etching time with 38 % phosphoric acid solution is in the range of 5 to 30 seconds.
Adhesives ; Dental Enamel* ; Incisor ; Tooth ; Water