No abstract available.
Crowns*

This study measured the relative displacements of the five-unit fixed partial dentures as cast with the same fixed partial dentures sectioned and assembled by investment-soldering, soldering stand-soldering, and cast-joining techniques. A total of fifteen specimens using a type IV gold alloy wee one-piece cast as control and then sectioned and assembled five test specimens for each method were prepared. A computerized three dimensional coordinate measuring machine and specially designed cylinder for this study were used. Displacement was defined by six displacement variables for the each of cylinders incorporated in each casting: three component displacements ( Lx, Ly, and Lz) and rotational displacements( thetax, thetay, thetaz). The global displacement was computed using the mathematical formula R= Global displacement ={{{{rm SQRT { (x'-x)^2 +(y'-y)^2 + (z'-z)^2} }} }} Under the conditions of this study, the following conclusions were drawn: 1. The investment-soldering group showed the largest mean value of final global displacements, followed by stand-soldering group, cast-joining group and one-piece cast group. However, between the mean values of final global displacement for the cast-joining group and one-piece cast group, there was no significant difference. 2. For investment-soldering and stand-soldering groups, the greater global displacements were recorded in soldering phase than in indexing or investing phase. 3. For one-piece cast group, the displacements occured mostly in the casting phase. And for castjoining group, there was no significant difference in global displacements among the fabrication procedures. 4. Intercentroidal distance decreased in framework-pattering, solder-indexing, solder-standing, and soldering phases, but increased in investment block-investing and casting phases. 5. Specially designed cylinder for touch-trigger type coordinate measuring machine was validated.
Abstracting and Indexing as Topic ; Alloys ; Denture, Partial, Fixed ; Investments ; Methods

The purpose of this study was to investigate the displacements of cast framework by torch soldering and electric soldering techniques. Specimen had two cylinders and connecting bar that had sectioned with 0.3mm gap at mid point. 10 of total specimens were divided into two groups. In torch soldered group, soldering investment block was made and conventional torch soldering procedure was carried out. In electric soldered group, electric soldering was carried out on the master cast without soldering investment block by using electric soldering machine(Dentapunkt DP 7, Kulzer, Germany). After soldering procedure, three dimensional coordinates of two centroids of each cylinder were measured by three dimensional coordinate measuring machine. The intercentroidal displacement and global displacement were calculated and then, these values were compared and evaluated. The results were obtained as follows: 1. Intercentroidal distances of specimens decreased after both soldering procedures, and the decrease in intercentroidal distance was greater for torch soldered group than for electric soldered group 2. Global displacements of torch soldered group were greater than those of electric soldered group
Investments

PURPOSE: The purpose of this study was to compare the fracture strength of the zirconia monolithic all-ceramic crowns according to the thickness (0.5mm, 0.8mm, 1.1mm) and metal-ceramic crowns (1.0mm, 1.5mm). MATERIAL AND METHOD: Twelve crowns for each of 3 zirconia crown groups were fabricated using CAD/CAM system (Kavo, Germany) and twelve crowns for each of 2 metal-ceramic crown groups were made by the conventional method. All crowns were luted to the metal dies using resin cement. Half of the specimens were exposed to thermocycling (5-55degrees C, 1 Hz) and cyclic loading (300,000 cycles, 50N). Subsequently, all crowns were mounted on the testing jig in a universal testing machine. The load was directed at the center of crown with perpendicular to the long axis of each specimen until catastrophic failure occurred. Analysis of variance and Tukey multiple comparison test (P<.05) were used for statistical analysis of all groups, and paired t-test (P<.05) was followed for statistical comparison between each groups'fracture load before and after cyclic loading. RESULTS: 1. The fracture strength of the zirconia monolithic crowns and the metal-ceramic crown increased as thickness increased (P<.05). 2. The cyclic loading and thermocycling significantly decreased the fracture strength of the zirconia monolithic crowns (P<.05). 3. The standard deviation of fracture strength of the zirconia monolithic crowns was very low. CONCLUSION: The fracture strength of the zirconia monolithic crowns for the posterior area tends to be higher with thickness increased and 0.8mm or over in thickness is recommended to have similar or over the fracture strength of metal-ceramic crowns.
Axis, Cervical Vertebra ; Crowns* ; Resin Cements

The purpose of this study was to investigate the effects of investing conditions on the marginal discrepancy of conical telescope outer crown with Co-Cr-Ti alloy(Dentitan) and to compare the marginal discrepancy and the retention force of outer crowns using different pattern materials (plastic foil, casting wax, pattern resin). To evaluate the effects of investing conditions on the marginal discrepancy, patterns with plastic foil were invested under three different liquid/powder ratio conditions using phosphate bonded investment (Univest-nonprecious): standard, 10% decreased and 10% increased. At each liquid/powder ratio condition, metal ring was lined with single or double layers of ceramic ring liner. The marginal discrepancy of outer crown at different investing conditions was measured by x 100 compact measuring microscope(STM5, Olympus, Japan). For measurement of the marginal discrepancy and the retention force of outer crown using different pattern materials, the investing condition of 10% decreased liquid/powder ratio and double layers of ring liner was selected because this investing condition resulted in the best fit of outer crown. Marginal discrepancy was measured in the same way above and retention force on universal testing machine. Under the conditions of this study, the following conclusions were drawn: 1. The thickness of ring liner had more influence on the marginal discrepancy of outer crown than the liquid/powder ratio, and the acceptable marginal fitness could not be expected at the investing condition directed by investment manufacturer. 2. There were no differences in the marginal discrepancy of outer crown among three different pattern materials 00.05). 3. Casting wax showed the greatest retention force(1640g) of outer crown, followed by pattern resin(1110g), plastic foil(820g). However, there was no significant difference between plastic foil and pattern resin(p>0.05). 4. Plastic foil showed the least variation in marginal discrepancy and retention force.
Alloys* ; Ceramics ; Crowns* ; Investments ; Plastics ; Telescopes*

STATE OF PROBLEM: Zirconia all-ceramic restoration fabricated with CAM system is on an increasing trend in dentistry. However, evaluation of the marginal and internal fits of zirconia bridge seldomly have been reported. PURPOSE: This study was to evaluate the fit of margin and internal surface in posterior 3-unit zirconia bridge framework fabricated with CAM system(DeguDent, Germany). MATERIAL AND METHOD: Preparations of secondary premolar and secondary molar on artificial resin model were performed for fabrication of 3-unit posterior bridge framework. Fits of 5 zirconia bridge framework were compared with 5 precious ceramo-metal alloy framework(V-GnathosPlus, Metalor, Switzerland), and prepared margins were designed to chamfer and shoulder finishing line. Each framework was cemented to epoxy resin model with reinforced glass ionomer(FujiCEM, GC Co., Japan), embedded in acrylic resin and sectioned in two planes, mesiodistal and buccolingual. Samples were divided into six pieces by sectioning and had two pieces of each surface(i.e. mesial, distal, buccal and lingual surface) per abutment, so there were eight measuring points in each abutment. External gap was measured at the margin and internal gaps were measured at the margin, axial and occlusal surface. Gaps were observed under the measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of * 100. T-test were used to determine the statistic significance of the different gaps between zirconia and metal framework. RESULTS AND CONCLUSION: 1. External and internal marginal gaps of zirconia and metal framework were in clinically acceptable range. External marginal gaps were not different significantly between zirconia(81.9 micrometer) and metal(81.3 micrometer) framework and internal marginal gaps of zirconia(44.6 micrometer) were smaller than those of metal framework(58.6 micrometer). 2. Internal axial gaps of zirconia framework(96.7 micrometer) were larger than those of metal framework(78.1 micrometer) significantly and adversely, internal occlusal gaps of zirconia framework(89.4 micrometer) were smaller than those of metal framework(104.9 micrometer) significantly. 3. There were no significant differences in external and internal marginal gaps between chamfer and shoulder finish line when zirconia frameworks were fabricated.
Alloys ; Bicuspid ; Dentistry ; Glass ; Molar ; Shoulder

No abstract available.
Cholestasis, Intrahepatic*

The authors report a case of giant-cell tumor of the right middle cranial fossa floor a 43-year-old man. His presentation, characteristic magnetic resonance image findings, treatment, and 2-year follow-up result are described. The patient about this rare neoplasm of the skull base are also reviewed.
Adult ; Cranial Fossa, Middle* ; Follow-Up Studies ; Humans ; Skull Base

This study was conducted to figure out the prevalence of symptomatic peripheral arterial disease among teachers. The data used in the analysis were based on 831 questionnaires, filled out by elementary, middle and high school teachers in Taegu, between September 5, 1994 and October, 4 in 1994. The prevalence of symptomatic peripheral arterial disease was 1.7% among teachers, 1.2% for definite claudication, 0.5% for atypical claudication, 1.7% for serious illness grade I, and 0% for the walk pain grade II. The prevalence was 1.9% for the male and 1.4% for the female. The prevalence by age group was 1.3% for less than 39, 1.6% for the forties, and 2.9% for the over fifties. The results shows that the prevalence increases as the age. The prevalence was 1.8% for the smoking group, 1.6% for the non-smoking group, 2.0% for the alcohol drinking group, and 1.5% for the non-alcohol drinking group. The prevalence for the lean group based on Body Mass Index(BMI) was 1.3%, 1.8% for the normal group, 2.1% for the obese group, 2.2% for the behavior pattern A, and 1.4% for the behavior pattern B. This study shows that the peripheral arterial disease may be considered as an important health problem among teachers.
Alcohol Drinking ; Daegu ; Drinking ; Female ; Humans ; Male ; Peripheral Arterial Disease* ; Prevalence* ; Questionnaires ; Smoke ; Smoking

Malignant transformation of benign cystic teratomas of the ovary is rare, with an incidence rate of 1-3%. The most common malignancy associated with benign cystic teratoma of the ovary is squamous cell carcinoma, which represents 90% of malignant transformations, followed by adenocarcinoma and carcinoid. Primary malignant neuroectodermal tumor in a mature cystic teratoma is extremely rare and microscopically can be subclassified as differentiated, primitive, and anaplatic. We experienced a case of primitive neuroectodermal tumor (PNET) associated with mature cystic teratoma of the ovary in a 11-year-old girl. Grossly, the ovary was a unilocular cyst which contained sebum material and disclosed several large, yellow to gray-tan polypoid excresences attached to the inner cystic wall. Except a large, fish-flesh, soft mass, the other polypoid masses were covered with sebum and contained small pieces of cartilage and tooth, and microscopically represented as mature teratoma. The large, fish-flesh, soft mass disclosed sheets and lobules of closely packed small cells with thin fibrovascular septa, which frequently replacing and encroaching the mature cystic teratoma. The small tumor cells were uniform and made up of round to oval nuclei with coarse chromatin and prominent nucleoli, very similar to those of PNET of the central nervous system.
Incidence ; Cysts ; Adenocarcinoma