This study was performed to evaluate the effect of aging and thermal cycling on the biaxial flexure strength of four commercially available veneering resin composites for crown(Dentacolor : DC, Artglass : AG, Esternia : ET and Targis : TG). Disc specimens were fabricated in a teflon mold giving 12mm in diameter and 1mm in thickness. All samples were divided into 4groups. Group 1 was dried in a dessicator at 25degrees C for 30 days. Group 2 was immersed in distilled water at 37degrees C for 30 days. Group 3 was immersed in distilled water at 65degrees C for 30 days. Group 4 was subjected to 10,000 thermal cycles between 5degrees C and 55degrees C, and the immersion time in each bath was 15 seconds per cycle. Biaxial flexure test was conducted using the ball-on-three-ball method at the cross head speed of 0.5mm/min and fracture surfaces were observed with scanning electoron microscope. The results obtained were summarized as follows ; 1. Weibull modulus values, except for the AG group, decreased after thermal cycling treatment. 2. Biaxial flexure strength values of aging group at 37degrees C were th lowest in all sample groups. Except for the DC group, strength values were significntly decreased for the drying group. 3. After thermal cycling test, the highest value of biaxial flexure strength of 188.8 MPa was observed in the ET group and the lowest value of 73.2 MPa was observed in the DC group. The strength values showed the significant differences in each group (p<0.05). 4. Observation of surfaces after thermal cycling test revealed the ditching in the part f surrounding large fillers.
Aging* ; Baths ; Crowns* ; Fungi ; Head ; Immersion ; Polytetrafluoroethylene ; Water

No abstract available.

PURPOSE: The intent of this study was to evaluate the effects of curing conditions on selfcuring denture base resins to find out proper condition in self-curing resin polymerization. MATERIALS AND METHODS: In this study, 3 commercial self-curing denture base resins are used: Vertex SC, Tokuso Rebase and Jet Denture Repair Acrylic. After mixing the self curing resin, it was placed in a stainless steel mold(3x6x60mm). The mold containing the resin was placed under the following conditions- in air at 23 degrees C, or in water at 23degrees C; or in water at 23degrees C under pressure(20psi); or in water at 37degrees C under pressure(20psi); or in water at 50degrees C under pressure(20psi); or in water at 65degrees C under pressure(20psi), respectively. Also heatcuring denture base resin is polymerized according to manufacturers' instructions as control. Fracture toughness was measured by a single edge notched beam(SENB) method. Notch about 3mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed 0.5mm/min and fracture surface were observed under measuring microscope. RESULTS AND CONCLUSION: The results obtained were summarized as follows : 1. The fracture toughness value of self-curing denture base resins were relatively lower than that of heat-curing denture base resin. 2. In Vertex SC and Jet Denture Repair Acrylic, higher fracture toughness value was observed in the curing environment with pressure but in Tokuso Rebase, low fracture toughness value was observed but there was no statistical difference. 3. Higher fracture toughness value was observed in the curing environment with water than air but there was no statistical difference. 4. Raising the temperature in water showed the increase of fracture toughness.
Axis, Cervical Vertebra ; Denture Bases* ; Denture Repair ; Dentures* ; Diamond ; Fungi ; Polymerization ; Polymers* ; Stainless Steel ; Water

BACKGROUND: Hair growth is spontaneously activated from quiescent bulge stem cells or is activated from precocious anagen. Upon spontaneous activation of hair growth or activation induced by nuclear factor of activated T cells c1 (NFATc1) inhibitors, NFATc1 expression is lost and cyclin dependent kinase (CDK4) repression is relieved. OBJECTIVE: The purpose of this study was to investigate the mechanisms of cyclosporine as a hair cycle regulator in the treatment of Alopecia areata (AA). METHODS: In this study, we planned to investigate the hair growing properties of cyclosporine in vitro conditions. Briefly, the effects of different concentrations of cyclosporine (200, 500, 1,000, 2,000 mmol) on the growth of cultured hair follicles were examined through the expression of NFATc1 and CDK4. RESULTS: NFATc1 was downregulated and CDK4 expression was upregulated especially in the bulge areas, outer root sheath and hair bulb matrix cells as the concentration of cyclosporine increased. CONCLUSION: Cyclosporine induces CDK4 expression by NFATc1 suppression, which acts to relieve repressed CDK4, resulting in hair growth. In conclusion, cyclosporine is one of the candidates as a therapeutic agent for the treatment of hair loss.
Alopecia Areata ; Cyclins ; Cyclosporine* ; Hair Follicle ; Hair* ; Phosphotransferases ; Repression, Psychology ; Stem Cells ; T-Lymphocytes

Dental ceramics have good aesthetics, biocompatibility, low thermal conductivity, abrasion resistance, and color stability. However, poor resistance to fracture and shrinkage during firing process have been limiting factors in their use, particularly in multiunit ceramic restorations. A new method for making all-ceramic crowns that have high strength and low processing shrinkage has been developed and is referred to as the Vita In-Ceram method. This study was performed to investigate the effect of Ce02 addition in borosilicate glasses on the strength of alumina-glass composites. Porous alumina compacts were prepared by slip casting and sintered at 1,100 degrees C for 2 hours. Dense composites were made by infiltration of molten glass into partially sintered alumina at 1,140 C for 4 hours. Specimens were polished sequentially from #800 to #2000 diamond disk, and the final surface finishing on the tensile side was received an additional polishing sequence through 1,cm diamond paste. Biaxial flexure test was conducted by using ball-on-three-ball method at a crosshead speed of 0.5mm/min. To examine the microstructural aspect of crack propagation in the alumina-glass composites, Vickers-produced indentation crack was made on the tensile surface at a load of 98.0 N and dwell time of 15 sec, and the radial crack patterns were examined by an optical microscope and a scanning electron microscope. The results obtained were summarized as follows ; 1. The porosity rates of partially sintered alumina decreased with the rising of firing temperature. 2. The maximum biaxial flexure strength of 423.5MPa. in alumina-glass composites was obtained with an addition of 3 mol% Ce02 in glass composition and strength values showed the aspect of decrease with the increase of Ce02 content. 3. The biaxial flexure strength values of alumina-glass composites were decreased with rising the firing temperature. 4. Observation of the fracture surfaces of alumina-glass composites indicated that the enhancement of strength in alumina-glass composites was due to the frictional or geometrical interlocking of rough fracture surfaces and ligamentary bridging by intact islands of materials left behind the fracture front.
Aluminum Oxide ; Ceramics ; Crowns ; Diamond ; Esthetics ; Eyeglasses ; Fires ; Friction ; Glass* ; Islands ; Porosity ; Thermal Conductivity

PURPOSE: Tuberous sclerosis is an autosomal dominant multisystemic neurocutaneous syndrome characterized by the development of multiple hamartoma distributed through the body, skin, brain, heart, kidney, and lung. The classic triad is seizure, mental retardation, and facial angiofibroma. We experienced a case of a tuberous sclerosis associated with the facial lesion and multiple masses on scalp, forehead, and right lower extremity. METHODS: This a 34-year-old male patient had subependymal giant cell astrocytoma in brain and multiple angiomyolipoma in both kidneys. Tangential excision with razor blade and dermabrasion were done on the centrofacial area. We excised other lesions and the mass on scalp was excised and covered with split thickness skin graft. RESULTS: The histopathological finding revealed that the facial lesion was angiofibroma and the others were multiple fibroma. CONCLUSION: In our case of tuberous sclerosis, we chose the tangential excision to remove the large nodules of angiofibroma, and then dermabrasion was used to smooth the final contour. The patient appeared to have a good results from this treatment modality. But, tuberous sclerosis is an disease that needs long term follow-up to check up the recurrence of skin problem.
Adult ; Angiofibroma ; Angiomyolipoma ; Astrocytoma ; Brain ; Dermabrasion ; Extremities ; Fibroma ; Forehead ; Hamartoma ; Heart ; Humans ; Intellectual Disability ; Kidney ; Lung ; Male ; Neurocutaneous Syndromes ; Recurrence ; Scalp ; Seizures ; Skin ; Tuberous Sclerosis

PURPOSE: The aim of this study was to evaluate the shear bond strength between Ni-Cr alloy and composite resin using universal adhesive systems coMPared to conventional method using metal primers. MATERIALS AND METHODS: For this study, a total of 120 cast commercial Ni-Cr alloy (Vera Bond 2V) disks were embedded in acrylic resin, and their surfaces were smoothed with silicon carbide papers and airborne-particle abrasion. Specimens of each metal were divided into 6 groups based on the combination of metal primers (Metal primer II, Alloy primer, Metal & Zirconia primer, MKZ primer) and universal adhesive systems (Single Bond Universal, All Bond Universal). All specimens were stored in distilled water at 37degrees C for 24 hours. Shear bond strength testing was performed with a universal testing machine at a cross head speed of 1 m/min. Data (MPa) were analyzed using one-way ANOVA and the post hoc Tukey's multiple comparison test (alpha=.05). RESULTS: There were significant differences between Single Bond Universal, All Bond Universal, Metal Primer II and Alloy Primer, MKZ Primer, Metal & Zirconia Primer (P<.001). CONCLUSION: Universal Adhesive system groups indicated high shear bond strength value bonded to Ni-Cr alloy than that of conventional system groups using primers except Metal Primer II. Within the limitations of this study, improvement of universal adhesive systems which can be applied to all types of restorations is recommended especially non-precious metal alloy. More research is needed to evaluate the effect of silane inclusion or exclusion in universal adhesive systems.
Adhesives ; Alloys* ; Head ; Water

BACKGROUND/AIMS: It has been acknowleged that diverse factors such as Hepatitis B or C virus, alcohol, food carcinogens, and environmental or genetic factors are involved in hepatocellular carcinogenesis. In the molecular biologic aspect, suppression of tumor suppressor gene or amplification of oncogene, abnormal regulation of cell cycle-related proteins, abnormal apoptosis mechanism, and diverse growth factors are reported to be factors that contribute to hepatocellular carcinogenesis. In this study, the genetic difference between hepatocellular carcinoma tissue and surrounding non-hepatocellular carcinoma tissue has been investigated to identify genes that are deleted, diminished, amplified, or newly developed in hepatocellular carcinoma using differential gene expression. METHOD: We studied each of 12 biopsy samples of hepatocellular carcinoma and surrounding non-hepatocellular carcinoma tissues obtained during surgical resections. Random arbitrarily primed-polymerase chain reaction (RAP-PCR) was applied for differential gene expression. The genes that are deleted, diminished, or amplified, newly developed in hepatocellular carcinoma are cloned, sequenced, and then identified by BLAST search, some genes are characterized by eletrophoresis motility shift assay (EMSA) and in situ hybridization. RESULTS: We identified the various, diverse genes classified as tumor suppressor genes, oncogenes, growth factor genes, and some kinds of transcription factors. Some of these genes were identified to be repressed, deleted or diminished, others were amplified, or newly developed in hepatocellular carcinoma tissues. CONCLUSIONS: RAP-PCR is a good method in the identification of the gene associated with hepatocellular carcinoma. The result in this study shows that so many genes are different between hepatocellular carcinoma and surrounding non- hepatocellular carcinoma tissues, and that the genes related with hepatocellular carcinogenesis may be predicted. Further studies are necessary for analyzing the relationship bet
Apoptosis ; Biopsy ; Carcinogenesis ; Carcinogens ; Carcinoma, Hepatocellular* ; Clone Cells ; Gene Expression* ; Genes, Tumor Suppressor ; Hepatitis B ; In Situ Hybridization ; Intercellular Signaling Peptides and Proteins ; Oncogenes ; Transcription Factors

Human toxocariasis is defined as the infection of a human host by the larval stages of Toxocara canis, a common intestinal parasite of dogs. We experienced a patient with hypereosinophilic syndrome involving liver and stomach caused by human toxocariasis. The diagnosis of toxocariasis was confirmed by detecting serum specific IgE antibody to Toxocara excretory-secretory antigens (TES-Ag) by ELISA and IgG immunoblot analysis, with high sensitivity and specificity for the diagnosis of toxocariasis. Toxocariasis should be considered one of the causative diseases inducing hypereosinophilic syndrome in this country.
Animals ; Diagnosis ; Dogs ; Enzyme-Linked Immunosorbent Assay ; Eosinophilia ; Humans* ; Hypereosinophilic Syndrome* ; Immunoglobulin E ; Immunoglobulin G ; Liver ; Parasites ; Sensitivity and Specificity ; Serologic Tests* ; Stomach ; Toxocara ; Toxocara canis ; Toxocariasis*

Common clinical manifestations in patients with IgG subclass deficiency include recurrent respiratory tract infection, recurrent otitis media and sinopulmonary infection by virus or bacteria. The administration of intravenous immunoglobulin (IVIG) has been regarded as the most effective therapy in these patients. We experienced a 22-year-old patient with IgG3 subclass deficiency and recurrent fungal infection of oral cavity and lips. IVIG was given at 0.2g/kg/dose twice a month for 6 months. After treatment with IVIG, the patient improved clinically.
Bacteria ; Humans ; Immunoglobulin G* ; Immunoglobulins ; Immunoglobulins, Intravenous ; Lip ; Mouth* ; Otitis Media ; Respiratory Tract Infections ; Young Adult