No abstract available.

No abstract available.
Denture, Partial, Removable*

The indirect technique for making cast restoration requires that dies be as accurate and durable as possible. Currently, stone is the most commonly used material for die. However, it has some problems such as the weakness in its strength and low abrasion resistance. Recently, epoxy resin die systems have become available. The purpose of this study was to examine two commercially available resin die systems and evaluate some characteristics for their clinical performance. This study evaluated the dimensional accuracy of epoxy resins and their wettability with impression materials. In this study, the first experiment was about dimensional accuracy of different die materials. The master model was made of stainless steel. 10 models were made of two epoxy resins (Die-epoxy, Tri-epoxy) and a die stone (Fujirock) each. Occlusal diameter (Dimension I), occluso-gingival height (Dimension II), and interabutment distance (Dimension III) wee measured in each model. Next, the contact angles of die materials with impression materials were observed. The blocks were made of polyether, hydrophilic additional silicone, polysulfide impression materials. By dropping the same amount (0.05ml) of Tri-epoxy, Die-epoxy, and die stone on the blocks, 10 samples of each die material were made. After setting of materials, the contact angles were measured. The results of this study were as follows. 1. The expansion of stone die and the shrinkage of resin dies in occlusal diameter were observed, and stone and Tri-epoxy were expanded and Die-epoxy was shrinked in occluso-gin-gival height. There was little change among materials in interabutment distance (p>0.05). 2. In comparison with the mater model, Tri-epoxy had the least variation in measurement of the three die systems examined. Did-epoxy was next, and die stone showed the greatest variation. 3. The compatibility of die stone for polyether, hydrophilic additional silicone, polysulfide decreased in order, wherease epoxy materials had the decreased compatibility for polyether and polysulfide, hydrophilic additional silicone in order. It was not statistically different between polyether and polysulifide (p>0.05). 4. The contact angles of Tri-epoxy, Die-epoxy, die stone were getting bigger in order.
Epoxy Resins* ; Silicones ; Stainless Steel ; Wettability

The purpose of this study was to evaluate and compare the fit of denture bases processed by injection pressing technic using laser scanner of reverse engineering technic. The auther duplicated 20 maxillary edentulous models and 20 mandibular edentulous models, which were scanned on HYSCAN 45C 3D SCANNER(Hymarc Co., Canada). The scanned data was stored in the personal computer using SURFACER (Imageware Co., U.S.A.) software program. After 40 dentures were cured by PERform Inkovac system. SR-Ivocap system, Palajet system, and Sulfon system, they were stored in water at room temperature for 24 hours. The dentures were scanned on HYSCAN 45C 3D SCANNER(Hymarc Co. Canada). The scanned data were stored in the personal computer using SURFACER (Imageware Co., U.S.A) software program. By overlapping two images using the same program, the fit between two surfaces was scaled by positive and negative errors. The obtained results were as follows : 1. In the upper denture, most of the positive errors occurred on the lingual side of anterior alveolar ridge and the negative errors were on the flange of denture bases. 2. In the lower denture, most of the positive errors occurred on the inner side of lingual flange and the negative errors were on the border of anterior labial flange areas. 3. There were no statistical differences among the positive errors of the four types of inject-ion denture curing methods and also no statistical differences between negative errors except only in negative maximum errors. 4. In PRERform system and SR-Ivocap system, they have the tendency of inaccurate fit lower denture bases comparing to that of upper denture bases. 5. The negative error scales were greater than the positive error scales in all types of inject-ion denture curing methods.
Alveolar Process ; Denture Bases* ; Dentures* ; Microcomputers ; Water ; Weights and Measures

No abstract available.

No abstract available.

The purpose of this study was to compare the accuracy of currently used elastomeric impression materials for complete arch impression taking. Five elastomers (Impregum, Permlastic, Express, Extrude, Examix) and one Irreversible hydrocolloid (Aroma-fine) were tested. For each material, 5 impressions were made of stainless steel model to which five tapered posts were attached. Custom trays were used for polyether and polysulfide impression materials, and putty/wash two step technique was used for addition polyvinylsiloxane impression materials. Improved stone models were poured to all impressions. Accuracy of the materials was assessed by measuring ten distances on stone dies poured from impressions of the master model. All measurements for master and improved stone models were with three dimensional measuring machine. The results were as follows 1. The dimensional accuracy of polyether, extrude, and examix were significantly superior to polysulfide, exress, and alginate in reproducing full arch mode (p<0.05). 2. There were no statistical differences in dimensional accuracy for full arch impression between polyether, extrude and examix (p>0.05). 3. there were no statistical differences in dimensional accuracy between polysulfide, express, and alginate (p>0.05). 4. There were no statistical differences between addition polyvinyl siloxane materials (p>0.05). 5. There were no statistical differences between anterior-posterior and lateral dimensional changes of all impression materials (p>0.05).
Colloids ; Elastomers* ; Polyvinyls ; Siloxanes ; Stainless Steel

No abstract available.
Carcinogenesis* ; Humans* ; Oncogenes*

No abstract available.
Carcinogenesis*

Deep vein thrombosis is a frequently lethal complication following musculoskeletal surgery and skeletal trauma. For this study on incidence of deep vein thrombosis, we examined the data on 40 patients with contrast venography. Thrombosis limited to the veins in the calf of the leg was shown in 10 patients by venography. None of these patients had clinical symptoms of deep vein thrombosis or indicating embolism. We therefore concluded that the incidence of deep vein thrombosis of the lower extremity after injury or operation in Korea is not so rare as was considered before.
Embolism ; Humans ; Incidence ; Korea ; Leg ; Lower Extremity ; Phlebography ; Thrombosis ; Veins ; Venous Thrombosis