STATEMENT OF PROBLEM: Recently Yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) has been introduced due to superior flexural strength and fracture toughness compared to other dental ceramic systems. Although zirconia has outstanding mechanical properties, the phenomenon of decrease in the life-time of zirconia resulted from degradation in flexural strength after low temperature aging has been reported. PURPOSE: The objective of this study was to investigate degradation of flexural strength of Y-TZP ceramics after various low temperature aging treatments and to evaluate the phase stability and micro-structural change after aging by using X-ray diffraction analysis and a scanning electron microscope (SEM). MATERIAL AND METHODS: Y-TZP blocks of Vita In-Ceram YZ (Vita Zahnfabrik, Bad Sackingen, Germany) were prepared in 40 mm (length) x 4 mm (width) x 3 mm (height) samples. Specimens were artificially aged in distilled water by heat-treatment at a temperature of 75, 100, 125, 150, 175, 200, and 225degrees C for 10 hours, in order to induce the phase transformation at the surface. To measure the mechanical property, the specimens were subjected to a four-point bending test using a universal testing machine (Instron model 3365; Instron, Canton, Mass, USA). In addition, X-ray diffraction analysis (DMAX 2500; Rigaku, Tokyo, Japan) and SEM (Hitachi s4700; Jeol Ltd, Tokyo, Japan) were performed to estimate the phase transformation. The statistical analysis was done using SAS 9.1.3 (SAS institute, USA). The flexural strength data of the experimental groups were analyzed by one-way analysis of variance and to detect statistically significant differences (alpha= .05). RESULTS: The mean flexural strength of sintered Vita In-Ceram YZ without autoclaving was 798 MPa. When applied aging temperature at below 125degrees C for 10 hours, the flexural strength of Vita In-Ceram YZ increased up to 1,161 MPa. However, at above 150degrees C, the flexural strength started to decrease. Although low temperature aging caused the tetragonal-to-monoclinic phase transformation related to temperature, the minimum flexural strength was above 700 MPa. CONCLUSION: The monoclinic phase started to appear after aging treatment above 100degrees C. With the higher aging temperature, the fraction of monoclinic phase increased. The ratio of monoclinic/tetragonal + monoclinic phase reached a plateau value, circa 75% above 175degrees C. The point of monoclinic concentration at which the flexural strength begins to decrease was between 12% and 54%.
Aged ; Aging ; Aluminum Oxide ; Ceramics ; Collodion ; Dental Porcelain ; Electrons ; Humans ; Phenothiazines ; Tokyo ; Water ; X-Ray Diffraction ; Yttrium ; Zirconium

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

One important aspect for patients with spinal cord injury is adjustment to altered sexual activity. We studied for the evaluation of the sexual function in patients with spinal cord injury. The following results were obtained. l. 46 spinal cord injury patients were interviewed concerning erections, coitus, ejaculation and orgasm. 32 (69.6%) of t6 spinal cord injury patients were returned erections: 14 (30.4%) patients attempt coitus were successful, 7 (15.2%) patients could ejaculate, and 3 (6.5%) patients had orgasm. Psychogenic erection occur more with LMN lesions. Reflexogenic erection was shown at a higher incidence in patients with LMN lesion. In incomplete UMN lesions, both psychogenic and reflexogenic erection occur with the reflexogenic erection being more predominat. 2. In 8 impotent patients due to spinal cord injury, PBI, BCRLT and Papaverine test were measured. 1) In all patients PBI were greater than 0.75. This result was thought to be not related with vasculogenic factor in the impotence due to spinal cord injury. 2) In BCRLT LMN lesion and mixed type showed no response and delay, UMN lesion was within normal limit. 3) In 5 impotent patients due to spinal cord injury, 30mg papaverine was injected into the corpus cavernosum. One patient showed partial erection, and in 4 patient the penile rigidity was lasted upto 60-90 minutes. There was no complication. 3. The Jonas Silicone silver penile prosthesis was implanted in 3 spinal cord injury patients associated with the impotence and neurogenic bladder. There was no complication, no change of previous voiding pattern and no increased residual urine after implantation of penile prosthesis.
Coitus ; Ejaculation ; Erectile Dysfunction ; Humans ; Incidence ; Male ; Orgasm ; Papaverine ; Penile Prosthesis ; Sexual Behavior ; Silicones ; Silver ; Spinal Cord Injuries* ; Spinal Cord* ; Urinary Bladder, Neurogenic

Due to an increasing interest in esthetics and concerns about toxic and allergic reactions to certain alloys, patients and dentists have been looking for metal-free tooth-colored restorations. Recent improvement in technology of new all-ceramic materials and composite materials has broadened the options for esthetic single crown restorations. The aim of this investigation was to study the fracture strength of the metal-free posterior single crowns fabricated using two recently introduced systems, Empress 2 ceramic and Targis-Vectris. Forty premolar-shaped stainless steel dies with the 1mm-wide circumferential shoulder were prepared. Ten cylindrical crowns having a diameter of 8.0mm and total height of 7.5mm were fabricated for each crown system respectively (PFM, Empress staining technique, Empress 2 layering technique, and Targis-Vectris). The crowns were filled with cement and placed on the stainless steel dies with firm finger pressure. The crowns were then stored in distilled water at room temperature for 24 hours before testing. The crowns were tested for fracture strength in an Instron universal testing machine (Instron 6022). With a crosshead speed of 1mm/min the center of the occlusal surface of the crown was loaded using a 4mm-diameter stainless steel ball until fracture occurred. The fracture surfaces of the crowns were gold coated and examined using scanning electron microscopy (Jeol JSM-840 Joel Ltd., Akishima, Tokyo, Japan). Within the parameters of this study the following conclusions were drawn: 1. The mean fracture strength for PFM crowns was 5829(+/-906)N; for Empress staining technique the fracture strength was 1697(+/-604)N; for Empress 2 Layering technique the fracture strength was 1781N(+/-400)N, and the fracture strength for Targis-Vectris was 3093(+/-475)N. 2. The fracture strength of the PFM crowns was significantly higher than that of the Empress 2 and the Targis-Vectris crowns (P<0.05). 3. The fracture strength of the Targis-Vectris crowns was significantly higher than that of the Empress 2 crowns (P<0.05). 4. No statistical difference was found when Empress staining technique was compared with Empress 2 layering technique. 5. The SEM image of fracture surface of Empress 2 crown showed a very dense microstructure of the lithium disilicate crystals and the SEM image of fracture surface of Targis-Vectris crown showed indentations of Vectris and some fibers torn off from Vectris.
Alloys ; Ceramics* ; Crowns* ; Dentists ; Esthetics ; Fingers ; Humans ; Hypersensitivity ; Lithium ; Microscopy, Electron, Scanning ; Shoulder ; Stainless Steel ; Water

STATEMENT OF PROBLEM: Recently, resin cements have become more widely used and have been accepted as prominent luting cements. Current resin cements exhibit less microleakage than conventional luting cements. However, the constant contact with water and exposure to occlusal forces increase microleakage even in resin cements inevitably. Most bonding resins have been modified to contain a hydrophilic resin such as 2-hydroxyethylmethacrylate (HEMA) to overcome some of the problems associated with the hydrophobic nature of bonding resins. By virtue of these modifications, bonding resins absorb a significant amount of water, and there may also be significant stresses at bonding interfaces, which may adversely affect the longevity of restorations. Therefore the reinforcement of water stability of resin cement is indispensable in future study. PURPOSE: This study was conducted to examine the influence of water retention on microleakage of two resin cements over the period of 6 months. MATERIALS AND METHODS: 32 ex acted human teeth were used to test the microleakage of a single full veneer crown. Two resin cements with different components and adhesive properties - Panavia F (Kuraray Co., Osaka, Japan) and Super-Bond C&B (Sun Medical Co., Kyoto, Japan)- were investigated. The storage medium was the physiological saline solution changed every week for 1 month, 3 months, and 6 months. One group was tested after storage for 1 day. At the end of the each storage period, all specimens were exposed to thermocycling from 5.C to 55.C of 500 cycles and chewing simulation of 50,000 cycles, and then stained with 50% silver nitrate solution. The linear penetration of microleakage was measured using a stereoscopic microscope at x 40 magnification and a digital traveling micrometer with an accuracy of +/-3 um. Values were analyzed using two-way ANOVA test, Duncan's multiple range tests (DMRT). RESULTS: Statistically significant difference of microleakage was shown in the 3-month group compared with the 1-day or 1-month group in bot systems (p<0.05) and there were statistically significant differences in microleakage between the 3-month group and the 6-month group in both systems (p<0.05). The two systems showed different tendency in the course of increased microleakage during 3 months. In Panavia F, microleakage increased slowly throughout the periods. In Super-Bond C&B, there was no significant increase of microleakage for 1 month, but there was statistically significant increase of microleakage for the next 2 months. For the mean microleakage for each period, in the 3-month group, microleakage of Super-Bond C&B was significantly greater than that of Panavia F. On the other hand, in the 6-month group, microleakage of Panavia F was significantly greater than that of Super-Bond C&B (p<0.05). CONCLUSION: Within the limitation of this study, water retention of two different bonding systems influence microleakage of resin cements. Further studies with the longer observation periods in viro are required in order to investigate water stabilty and the bonding durability of the resin cement.
Adhesives ; Bite Force ; Crowns ; Hand ; Humans ; Longevity ; Mastication ; Resin Cements* ; Silver Nitrate ; Sodium Chloride ; Tooth ; Virtues ; Water*

No abstract available.
Kidney Failure, Chronic* ; Tuberculosis*

We studied the change or serum prostate specific antigen in 12 men of prostate cancer including 9 or stage C and 3 or stage D1 to monitor patients with adenocarcinoma of the prostate after radiation therapy. All patients had a pre-treatment prostate specific antigen level above 100ng/ml Median patient followup was 18 months (range 9 to 28 months) and serum prostate specific antigen levels were determined at 1 month and then 3 to 6 month intervals after radiation therapy. Initially, all patients had a decrease in prostate specific antigen within 6 months after treatment. Of 10 patients who had a decreasing prostate specific antigen to normal values, 1 patient had an increasing prostate specific antigen value at 21 months but 2 patients, a decrease in prostate specific antigen that never approaches normal had an increasing prostate specific antigen values at 12 months and 18 months. 3 patients(clinical stage D1/poorly differentiated ; 2 cases, clinical stage C/poorly differentiated; 1 case) who had an increasing prostate specific antigen values had a bone metastases. These observations indicate that patients who had a decreasing prostate specific antigen to normal values were low risk in disease progression and an increasing prostate specific antigen values after radiation therapy were correlated with progression to metastatic disease. We concluded that serial post-irradiation prostate specific antigen values may be useful in the early identification ofrecurrence and disease progression after radiation therapy for prostate cancer.
Adenocarcinoma ; Disease Progression ; Follow-Up Studies ; Humans ; Male ; Neoplasm Metastasis ; Prostate* ; Prostate-Specific Antigen* ; Prostatic Neoplasms* ; Reference Values

Norfloxacin is a new broad spectrum of antibacterial activity against both Gram-positive and Gram. negative bacteria. After oral administration of Norfloxacin, it produces high concentrations in the urine, so it has the excellent effect for the treatment of urinary tract infection. Norfloxacin was studied with respect to clinical effect in 115 patients with the urinary tract infection and the following results were obtained. 1. Excellent efficacy was 53% and efficacy rate was 90% in upper urinary tract infection(UTI). Efficacy rate for 20 patients with upper UTI without the underlying disease was 100%, and in 29 patients with underlying disease efficacy rate was 83%. 2. In upper UTI resistant for other antibiotics, efficacy rate was 78%. 3. In lower UTI excellent efficacy rate was 36% and efficacy rate was 71%. In gonococcal urethritis excellent efficacy rate was 76% and efficacy rate was 88%. 4. Eliminated rate of bacteria on culture findings were E. coli 93%, pseudononas 89%, proteus 100%, klebsiella 80%, gonococcus 88% and staphylococcus 80%. 5. Mild side effects such as epigastric pain, nausea, dizziness and itching sensation were seen in 5 cases. We consider Neutam-400 is one of the most effective agents in urinary tract infection.
Administration, Oral ; Anti-Bacterial Agents ; Bacteria ; Dizziness ; Humans ; Klebsiella ; Nausea ; Neisseria gonorrhoeae ; Norfloxacin ; Proteus ; Pruritus ; Sensation ; Staphylococcus ; Urethritis ; Urinary Tract Infections* ; Urinary Tract*

This investigation evaluated the fracture toughness (KIC) of eight currently available core materials, and relate the fracture toughness value to fractography analysis and surface characteristics using a atomic force microscope (AFM). Single-edge notched (SEN) test specimens (n=10) and compact tension (CT) test specimens (n=10) were prepared conforming to the ASTM Standard E-399 for a high copper amalgam, three composite core materials (Core-Max II, Core Paste, Bisfil Core), two reinforced composite core materials (Ti-Core, Ti-Core Natural), a resin-modified glass ionomer core material (Vitremer), and a conventional glass ionomer core material (Ketac-Molar). The specimens were tested with an Instron Universal Testing Machine. The maximum loads were measured to calculate the fracture toughness (KIC). Thereafter, fracture surfaces of SEN specimens of each material were investigated for fractography analysis using scanning electron microscope. And, disc-shaped specimens with 1mm thickness were fabricated for each material and were investigated under AFM for surface morphology analysis. The results were as follows : 1. Bisfil Core showed the highest mean fracture toughness regardless of test methods. 2. For the tooth-colored materials, Ti-Core Natural exhibited the highest fracture toughness. 3. Ketac Molar showed a significantly low fracture toughness when compared with the amalgam and the composite resin core materials (p<0.05). 4. The fracture toughness values obtained with the single-edge notched test, except Ketac Molar, were higher than those obtained in the compact tension test. 5. SEM revealed that the fracture surface of high fracture toughness material was rougher than that of low fracture toughness material. 6. AFM revealed that the surface particles of the composite resins were smaller in size, with a lower surface roughness than the glass ionomer core materials.
Composite Resins ; Copper ; Glass ; Molar

No abstract available.
Child* ; Hip Joint* ; Hip* ; Humans ; Synovitis*