The aim of this study was to compare wear resistance of resin denture teeth opposing various restorative materials. The wear resistance of conventional acrylic resin teeth (Trubyte Biotone) and three high-strength resin teeth(Bioform IPN, Endura, SR-Orthosit-PE) opposing different restorative materials (gold alloys, dental porcelain, composite resin) was compared. Wear tests were conducted with a sliding-induced wear testing apparatus which applied 100,000 strokes to the specimen in an mesio-distal direction under conditions of 100 stroke/min and constant loading of 1Kgf/tooth. Wear resistance of the resin denture teeth was evaluated by the following criteria : 1) wear depth, 2)weight loss, and 3) SEM observation. Results were as follows. 1. When opposed to gold alloys and composite resin, high-strength resin teeth showed superior wear resistance compared to acrylic resin teeth. But, in cases opposing dental porcelain, differences between the wear of the high-strength and acrylic resin teeth were not statistically significant (p<0.05). 2. When comparing wear resistance among high-strength resin teeth, opposing gold alloys, Endura was slightly more resistant and while in cases opposing dental porcelain, SR-Orthosit-PE was showed to be slightly resistant(p<0.05). 3. The wear of high-strength resin teeth was greater by 5 to 7 times when opposing porcelain and 2 to 3 times when opposing composite resin compared to gold alloys(p<0.05). 4. SEM observations of the wear surface showed that wear of resin teeth opposing gold alloys is a fatigue type of wear and wear of resin teeth opposing dental porcelain is fatigue and abrasion type of wear. Trubyte Biotone showed more severe fatigue type of wear than high-strength resin teeth. In conclusion, the use of dental porcelain should seriously be considered as restorative material in cases opposing resin denture teeth and improvement seems to be needed on resin teeth in the areas of wear resistance.
Dental Alloys ; Dental Porcelain ; Dentures* ; Fatigue ; Gold Alloys ; Stroke ; Tooth*

Although many studies on the cytotoxicity of the dental cast metal alloys and their components have been carried out, the results are rather conflicting because of the different type of cells used and the various experimental procedures taken. Recently, a number of scientists have claimed that it would be preferable to focus on the use of cells from relevant specific location of the human bodies. Consequently, the primary cultured oral keratinocyte derived from oral mucous along with nickel chloride and several of widely used dental cast base metal alloys(two-Ni-Cr alloys and one Co-Cr alloy)in domestic were selected for this study, from which 1) The amounts of released metal ions were determined using atomic absorption spectrometry, 2) The cytotoxicity of nickel chloride and dental cast base metal alloys was evaluated via MTT assay, and finally, 3) The amounts of released metal ions and the cytotoxicity of nickel chloride were correlated with the cytotoxicity of dental cast base metal alloys And, the results were summarized as follows ; 1. Nickel ion from Ni-Cr alloys and Cobalt ion from Co-Cr alloys resulted in maximum releasing rate during first 24 hours, followed by a decrease in releasing rate with time. Chromium ion were found to be minimal in all alloys. 2. In cytotoxic test, with 40muM, 80muM of nickel chloride, there were observed an increase in the relative cell number compared to control samples after 24 hours. With 160muM, there was found to be no difference in the relative cell number with control, except that 48 hour showed a increase in relative cell number. With 320muM, the relative cell number remained constant and decreased after 48 hours, and with 640muM, a continuing decrease in relative cell number was observed throughout test period. 3. The sensitivity of primary cultured oral epithelium to nickel was lower compared to the cells used in other studies. 4. CB-80 Soft and Regalloy showed no cytotoxicity to primary cultured oral epithelium and New crown resulted in a slight cytotoxicity. In conclusion, it was shown that the primary cultured oral keratinocytes could be applied successfully as testing cells in cytotoxicity test. Futhermore, the dental cast base metal alloys used in this study were found to be biocompatible.
Absorption ; Alloys* ; Cell Count ; Chromium ; Cobalt ; Crowns ; Epithelium ; Human Body ; Humans* ; Ions ; Keratinocytes* ; Nickel ; Spectrum Analysis

The principal cause of avulsion fracture of anterior superior iliac spine is sudden powerful contraction of sartorius muscle in strenuous sporting activities. The condition usually occurs in young people in whom the apophysis has still not firmly united to the ilium. We presented the three cases of avulsion fracture of anterior superior iliac spine which occurred during sprinting in Physical Fitness Test.
Ilium ; Physical Fitness ; Spine ; Sports

It appears that frequency of fractures of the aceta ulum is increasing with the number of automobiles on our roads and when they occur they seem to pose difficulties of management. Because, the anatomy of this region is complicated, making surgical approaches difficult. Second, the patients often have major associated injuries, making early operative treatment hazardous. Third, the fractures are often severly comminuted, leading many surgeons to beleave that operative reduction is impossible. Finally, and unfortunately, the fractures are often missed. The aim of treatment must be to restore the fractured acetabulum to its normal anatomy followed by early motion to promote healing and restore function. Undisplaced acetabular fractures have a good prosis with conservative treatment but patients with displaced fractures of the acetabulum not reduced by manipulation and traction should be considered candidates for open reduction. The author experienced 72 cases of acetabular fracture patients who were admitted to the department of Orthopaedic Surgery of Catholic Medical College and Center from January 1979 to August 1983. The results of 48 patients who were followed up over 6 months period were as follows; l. Among 72 cases(44 were male and 28 were female), the most common causes of acetabular fracture was pedestrian struck by car. 2. 56 were treated conservatively and 16 were treated surgically. The result were as follows; Excellent-15(31%), Good-23(48%), Fair-8(17%), Poor-2(4%). 3. 72 cases were classified by Letournel classification. The most common type was posterior wall fracture(14 cases), and second most was T-shaped fracture(13 cases). 4. If the grossly displaced fragments are present they should be reduced and fixed surgically if surgical approach can be done. 5. It is essential to understand the pathologic anatomy of the acetabulum in order to approach the acetabular fracture sefely and with maximum ease.
Acetabulum ; Automobiles ; Classification ; Clinical Study ; Humans ; Male ; Surgeons ; Traction

In order to evaluate the effects of trichloroethylene (TCE) on the central and autonomic nervous system, the brain stem auditory evoked potentials (BAEPs) and the electrocardiographic R-R interval variability (CV(rr)) were measured in three groups of workers (11) working in TCE degreasing process, workers (4) exposed to lead and two groups of workers (12) not exposed to any kinds of neurotoxicants. Two components of the CVrr reflecting parasympathetic activity (C-CV(rsa)) and sympathetic and parasympathetic activities (CCV(mwsa)) were examined. The TCE workers were exposed to TCE at the level of less than 1 hour per week while the degreasing material was changed. There were no differences in the latencies of BAEPS and CV(rr) and the components of the CV(rr) between control and TCE and lead groups. However, two lead workers had the blood lead level of less than 60 g/dl recommended as present biological guideline by the Ministry of Labor, showed the delayed latencies of V5 and I-V in BAEP. This results suggested that intermittent TCE erposure didn't affect the auditory nervous pathway and the autonomic nervous system, however, lead exposure might affect the central nervous system at the level of less than 60 g/dl in blood lead.
Autonomic Nervous System ; Brain Stem* ; Brain* ; Central Nervous System ; Electrocardiography ; Evoked Potentials, Auditory, Brain Stem* ; Trichloroethylene*

The aim of the spine fusion is to obtain the stability of the spine. Spinal fusion have been used for the treatment of tuberculosis and arrest of the progress of spinal deformity such as scoliosis. Nowadays the spine fusion is used often in conditions which present the instability; spondylosis, spondylolisthesis and the unstable postlaminectomy spine. Unilateral posterolateral fusion plus hemiposterior fusion were done only in the cases who had wide hemilaminectomy, while in rest of cases bilateral posterolateral fusion was indicated in this series. Fifty-two cases, treated with posterolateral lumber fusion during the period from June 1980 to Dec. 1985, were analysed clinically and radiologically and the following results were obtained. l. Among the 52 cases, 25 cases(48.1%) were male; and 27 cases(51.9%) were female; The youngest was 16 years of age and the oldest one was 63 years of age. Average age of the patient was 39.6 years. 2. Fifteen patients had spinal stenosis, 14 cases of spondylolisthesis, 11 cases of H.N.P., 6 cases of spondylolysis, 4 cases of tuberculous spondylitis and 2 cases of fracture-dislocation of lumbar spine. 3. As a method immobilization after operation, postoperatively hips spica cast was applied in 4 cases for 12 weeks, Norton-Brown back brace in 9 cases following 6 weeks of posloperative hip spica cast immobilization and Norton-Brown brace 39 cases following 2 weeks of postoperative bed rest. 4. In 41 cases bilateral posterolateral fusion was done, and in 11 cases unilateral posterolateral fusion plus hemiposterior fusion were done. The bony union was established within 4 months after bilateral posterolateral fusion in 37 cases and after unilateral posterolateral fusion in 9 cases. In 2 cases complete union was obtained within 6 months after fusion. 5. The union rate was 92.7% in bilateral posterolateral fusion and 90.9% in unilateral posterolateral fusion. There was no significant differences of the union rate between bilateral and unilateral fusion groups. Therefore, the unilateral posterolateral fusion is a suitable method in the treatment of mild spinal instability regardless of its causes. The procedure has benefits, such as short operation time, less blood loss, and less surgical burden to the patient.
Arthrodesis ; Bed Rest ; Braces ; Clinical Study ; Congenital Abnormalities ; Female ; Hip ; Humans ; Immobilization ; Male ; Methods ; Scoliosis ; Spinal Fusion ; Spinal Stenosis ; Spine ; Spondylitis ; Spondylolisthesis ; Spondylolysis ; Spondylosis ; Tuberculosis

No abstract available.
Blood Platelets* ; Hypertension, Pulmonary* ; Lung Diseases, Obstructive* ; Platelet Activation*

BACKGROUND: Melanocytes synthesize melanin pigment by the action of specific enzyme tyrosinase. Melanogenesis inhibitors such as ascorbic acid, kojic acid, arbutin, hydroquinone have been developed for use in cosmetic preparations for the skin hyperpigmentation,but they are still unsatisfactory to efficacy and tolerance. OBJECTIVES: In this study, the inhibitory effects of seaweed extract(SCH-T2)on tyrosinase activity and melanogenesis were investigated with B-16 melanoma cell line. METHODS: The patients were randomly assigned to one of three groups;control, diazepam, and ketorolac plus diazepam groups. Pain intensity was assessed 5 times at every ten minutes from the beginning of the peeling using visual analog scale(VAS). RESULTS: The seaweed was added with 21 organic solvents and extracted during 12 hours at 20-To evaluate the inhibitory effects of SCH-T2 on tyrosinase activity following to extraction time and temperature, this study was done at 4, 8, 12, 24, 72 hours and 4, 10, 20, 30, 40℃. Also, the effects of whitening agents (kojic acid, arbutin, licorice extracts,SCH-T2)on tyrosinase activity were compared by measuring the IC50,the concentration of the compound at which half of the original tyrosinase activity is inhibited. RESULTS: 1.The inhibitory effects of SCH-T2 on tyrosinase activity were high at 60-80% ethanol as an extraction organic solvent and showed increase in proportion to concentration following to extract concentration, but showed little differences following to extraction time and temperature. 2.SCH-T2 has relatively stronger inhibitory effects on tyrosinase activity than arbutin and licorice extracts. 3. The inhibitory effects of SCH-T2 on melanogenesis following to extract concentration were greatly increased at more than 20㎍/ml. CONCLUSION: This study showed that SCH-T2 seaweed extract has strong inhibitory effect on tyrosinase activity and melanogonesis. So, the results of this study suggest that SCH-T2 seaweed extract can be used as a new whitening agent.
Arbutin ; Ascorbic Acid ; Bleaching Agents ; Cell Line ; Diazepam ; Ethanol ; Glycyrrhiza ; Humans ; Ketorolac ; Melanins ; Melanocytes ; Melanoma ; Monophenol Monooxygenase ; Seaweed* ; Skin ; Solvents

No abstract available.

No abstract available.
Lichen Planus*