• The Journal of Korean Academy of Prosthodontics
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• v.56 no.1
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• pp.17-24
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• 2018

Lost wax technique of casting wax patterns has been used principally to make metal frameworks of removable partial dentures. Since the development of digital technology and CAD, metal frameworks can be built through digital surveying and framework designing. Many cases proved that resin patterns made by CAD printing method were well adapted to internal oral structure and final metal frameworks also showed good internal adaptation as well. The metal frameworks of a removable partial denture were made by both lost wax technique and CAD technique and were applied to a patient with severe alveolar bone loss. Using CAD data and fit checker, internal adaptation of both metal frameworks were evaluated by comparing the gap between surveyed crown and its structure. This study is to prove that metal frameworks by both techniques showed adaptation that can be applied in clinical field.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.3
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• pp.243-250
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• 2006

Due to high esthetic demands from patients, we are driven to fabricate natural-looking(form and color) restorations. In the past decade, the glass-ceramic in dentistry has been used as a material with variable crystals that affects the appearance, characteristics, and mechanical properties of metal-free fixed restoration. The conventional IPS Empress glass-ceramic is a heat-pressed, leucite reinforced material using the "lost wax" principle. This glass-ceramic has been successfully used for esthetic restorations such as all-ceramic crowns, inlays/onlays, and veneers for about 15 years. This article presents that the form and surface texture of clinical crown are duplicated by IPS-Empress system using "lost-wax technique".

• Journal of Korea Foundry Society
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• v.31 no.5
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• pp.249-254
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.74-80
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• 1999

In this study, a stereolithography apparatus (SLA) prototype is used as a master model to be transformed into the silicone pattern by vacuum tool forming. The tool for the first prototype is fabricated by using this silicone pattern. Following this procedure, a temporary tool with metal powder and epoxy for wax injection is prepared for the die set of quick change type which consists of upper and lower base die나 and an insert die. The die set of quick change type appears to be very effective in casting operation by changing tools rapidly. The original wax pattern is formed through the die set, and is made of lost-was. Finally the lost-wax pattern is applied to investment casting. The final casting product is checked regarding its dimensional accuracy.

• Journal of Conservation Science
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• v.28 no.4
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• pp.417-425
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• 2012

Bronze Mirror with fine linear designs in the bronze age shows the greatest alloy and casting skills of the day and presents the highest level of handcrafting and molding techniques. Lately, Lost-wax casting and sand-mould casting were used for the restoration of the national treasures of No. 141 and No. 143 Bronze Mirror with fine linear designs. Also the Principle Component Analysis, Microstructure Analysis, X-ray and SEM-EDS analysis were carried out on the restored Bronze Mirror with fine linear designs. Bronze Mirror that is made of sand-mould casting, hardly has a eutectoid and it is observed as a ${\alpha}$ dendrite. In contrast, Bronze Mirror that is made of lost-wax casting, the eutectoid has found through the ${\alpha}$ dendrite. As we compare lost-wax casting to the sand-mould casting through an analysis of restored Bronze Mirror, mostly, sand-mould casting has better castability and it seems that it brings a clear and equal Bronze Mirror as it has a low cooling rate. In this way, we are able to confirm that there is a big difference between the method by lost-wax casting and by sand-mould casting through an analysis of microstructure and restored Bronze Mirror. If such research will be continued, it will be an opportunity that investigates diverse methods of production techniques.

• Journal of Conservation Science
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• v.36 no.2
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• pp.123-142
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• 2020

We attempted an experimental study of lost-wax casting to reconstruct the Gilt-bronze pensive Bodhisattva; The main object we aimed to reconstruct was the Korean national treasure No.83, Gilt-bronze pensive Bodhisattva(Maitreya); thus, we scientifically analyzed and measured the alloy ratio and casting method. Initially, the alloy ratio we used during the preliminary experiment was Cu:Sn:Pb = 95.5:4.0:0.5; we then increased tin and lead by 2.5% to consider vaporization during the main experiment. After applying lost-wax casting, we realized that 30% rosin contributed to proper hardness after the wax hardness experiment. The microstructure revealed normal casting character(α-Cu, δ), and the results of the chemical analysis are identical to those of previous studies. The analysis of the mold suggests the presence of quartz powder for structural stability and fire-resistance along with other organic materials whose contribution is still unknown. We expect that our research will serve to provide basic data for advanced studies in the future.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.131-136
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• 2002

Protease activity in matured wax gourd sarcocarp was 0.19unit/0.5ml, immatured wax gourd sarcocarp 0.56unit, and matured wax gourd 24.35 unit, immatured wax gourd core 0.35unit. Protease activity in matured wax gourd sarcocarp to raw meat or raw pork was 13,0 unit, 7.4 unit, respectively, and that in wax gourd core to raw beef was 30.2 unit, and raw pork was 24.5 unit. Thermal stability of pretense in matured wax gourd sarcocarp was stable below 70$\^{C}$ when it was heated for 10 minutes. In case of 80$\^{C}$, the remaining activity was 21%, and at 90$\^{C}$, it was lost entirely. The absorption spectrum showed peak at 280nm. According to the HPLC analysis, casein was hydrolyzed into small size by protease in core or sarcocarp of matured was gourd and immatured wax gourd. Wax gourd diluted by 1/10 showed two peaks, one was from casein being hydrolyzed, and the other was from the increased molecular weight with coagulated casein. On the other hand, the molecular weight didin't increase in immatured wax gourd core diluted by 1/10. The result of dilution of 1/10 showed different pattern from undiluted one, but the peak of sarcocarp in matured wax gourd was 1 and the peak of core in immatured wax gourd was 5, and those of core and sarcocarp of immatured wax gourd were 3 respectively.

• Korean Journal of Agricultural Science
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• v.20 no.1
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• pp.9-17
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• 1993

Postharvest treatments such as polyethylene film wrapping, ethylene scrubber, and fruit coatings were compared to find a potential effect on the fruit quality in 'Fuji' apples during storage and simulated marketing. Polyethylene film wrapping appeared to be excellent in preventing weight loss during storage but fruits lost weight at a high rate when exposed to ambient temperature during simulated marketing. Also, surface cracking disorder was observed in parts of film-wrapped fruit under marketing condition after storage of 21 weeks. Ethylene scrubber effectively removed ethylene in polyetheylene bags but this effect reduced along with the increase of storage time. Although Prolong-treated fruits were good in appearance at 12-week storage, no beneficial effect was found on the inhibition of weight loss during storage as well as marketing. In addition, wax-like substances were accumulated on the surface after storage of 21 weeks, resulting in the reduction of marketability. Water soluble wax seemed highly effective on the inhibition of weight loss during storage and marketing. However, parts of fruit were severely injured probably due to the high concentration of wax. Undamaged fruit showed excellent appearance in shape and flesh quality even after 21 weeks of storage. Further study is required to find the proper concentration of wax.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.234-239
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• 2020

Purpose: We investigated the marginal fit between abutment and metal copings according to impression technique, wax block types, and metal types. Methods: We selected the traditional impression method of using rubber impression materials and the digital impression method of using oral scanners, three types of wax blocks, and two types of metal, both of which were domestically and commercially available, were selected to produce metal copings, and the marginal fit was determined through the use of silicon replication. Results: The measurements of axial wall fit revealed that the IYV specimens had the best fit, with a mean gap of 24.11±5.95 ㎛, followed by CEV, CHV, CSS, CSV, CES, CHS, and IYS specimens (mean: 33.44±8.41 ㎛). The differences were not statistically significant. The marginal gap measurements showed that the CEV specimen had the smallest gap, 17.25±4.13 ㎛, followed by the CSV, CHV, CSS, CES, CHS, IYV, and IYS specimen (mean: 43.47±15.63 ㎛). The differences were statistically significant. Conclusion: The axial wall fit of the metal coping (VeraBond2V; Aalba Dent, Inc., Fairfield, CA, USA) produced by the lost wax technique with the traditional impression method was excellent. The marginal fit of the metal coping (VeraBond 2V) produced by wax milling with the use of an oral scanner was also excellent. The marginal fit of the metal coping was within the clinically acceptable limits in all groups.

• The Journal of Advanced Prosthodontics
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• v.7 no.4
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• pp.294-302
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• 2015

PURPOSE. The purpose of this study was to verify the clinical-feasibility of additive manufacturing by comparing the accuracy of four different manufacturing methods for metal coping: the conventional lost wax technique (CLWT); subtractive methods with wax blank milling (WBM); and two additive methods, multi jet modeling (MJM), and micro-stereolithography (Micro-SLA). MATERIALS AND METHODS. Thirty study models were created using an acrylic model with the maxillary upper right canine, first premolar, and first molar teeth. Based on the scan files from a non-contact blue light scanner (Identica; Medit Co. Ltd., Seoul, Korea), thirty cores were produced using the WBM, MJM, and Micro-SLA methods, respectively, and another thirty frameworks were produced using the CLWT method. To measure the marginal and internal gap, the silicone replica method was adopted, and the silicone images obtained were evaluated using a digital microscope (KH-7700; Hirox, Tokyo, Japan) at 140X magnification. Analyses were performed using two-way analysis of variance (ANOVA) and Tukey post hoc test (${\alpha}=.05$). RESULTS. The mean marginal gaps and internal gaps showed significant differences according to tooth type (P<.001 and P<.001, respectively) and manufacturing method (P<.037 and P<.001, respectively). Micro-SLA did not show any significant difference from CLWT regarding mean marginal gap compared to the WBM and MJM methods. CONCLUSION. The mean values of gaps resulting from the four different manufacturing methods were within a clinically allowable range, and, thus, the clinical use of additive manufacturing methods is acceptable as an alternative to the traditional lost wax-technique and subtractive manufacturing.