• Journal of dental hygiene science
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• v.15 no.5
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• pp.673-678
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• 2015

The purpose of this study was to evaluate the reliability and accuracy of linear measurements in digital models compared to master model. A master model (ANKA-4; Frasaco GmbH, Tettnang, Germany) with the prepared upper full arch tooth was used. Four linear measurements were recorded between landmarks, directly on the master model and the digital models by a single examiner. Measurements were made with a digital caliper from manual model and with the software from the virtual models. The t-test for paired samples and intraclass correlation coefficient (ICC) were used for statistical analysis. The measurement of two methods showed good reliability. The mean differences between master and digital model were 0.06~0.12 mm. These in vitro studies show that accuracy and reliability of the digital impression is similar to that of the gold standard. Therefore digital impression was also considered to be a acceptable for placement clinically.

• Journal of the Korea Fashion and Costume Design Association
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• v.8 no.2
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• pp.1-16
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• 2006

The purpose of this study was to find out the various impressions that tone-on-tone coloration of shirts and ties gives. This experiment was based on the $2{\times}4{\times}4{\times}2$ factorial design: colors(red and blue), shirt tones(vivid, light, dull, and dark); tie tones(vivid, light, dull, and dark) and perceivers' gender(male and female). The materials in the experiment developed for this study were composed of 32 upper body photographs which were color printed and 27 bi-polar adjectives, each of which was graded into seven in its degree, were used to evaluate the impression. We unified those colors of shirts and neckties, and then made shirt and necktie tone different. The subjects of this research were 192 male and 192 female college students in Gyeongnam province including Jinju City The data was analyzed by using SPSS program. Analyzing methods were one-way ANOVA and LSD test. The items of the adjectives were classified into 5 impression dimensions - potency, activity, attractiveness, visibility and tenderness. All the image by the match of shirt and tie could be possible to make various images by the color, the shirt tone and the tie tone. Blue was given more effective potent image, vivid or light tone shirt in blue was the active image. As shirt and tie had different tone, regarded as the attractive image. Vivid tone tie was evaluated the visible image, light tone shirt is the tend image.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.6
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• pp.407-414
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• 2023

In this study, an automated jack-up system, applicable to various fields, was employed for 3D concrete printing and developed as a simultaneous liftable 3D concrete printing system. This developed printing system enables safe and precise jack-up by monitoring the measured jack-up distance using Pearson correlation coefficient analysis and a hydraulic system with interquartile range analysis in real-time during 3D concrete printing operations. It is possible to secure the quality of 3D concrete printing structures, which is essential for expanding the application of 3D concrete printing to construct larger structures. Specimens were printed using both conventional 3D concrete printing and simultaneous liftable 3D concrete printing to evaluate the system performance. The printed specimens were investigated using a 3D scanner. The layer-wise diameter and angle of intersection of the scanned specimens were measured, and an analysis was performed to verify the advantages of the simultaneous liftable 3D concrete printing.

• Korean Journal of Culture and Social Issue
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• v.12 no.4
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• pp.55-75
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• 2006

Most previous research on impression formation has been examined the effects of various informations exclusively within a category, either social category or individual characteristic. The present research examined and compared the priming effects of social category information (we and other) versus personality information (warm and cold) on impression formation. In Study 1, participants primed subliminally with combinations of social category and personality information (we/warm, we/cold, other/warm, and other/cold) were asked to rate faceial pictures on the good-bad and likable-dislikable dimensions. The analysis revealed only the significant main effects of social category information but not any effects of personality information on both the impression dimensions. In Study 2 in which participants were primed with either social category or personality information exclusively, priming of social category information influenced the judgments of likable-dislikable dimension and that of personality information influenced the judgments of good-bad dimension. These results suggest that personality information influences impression in general even though its impacts may be overwritten by social categorical information. The findings were discussed with its implication of everyday's impression formation and the cultural psychological perspectives.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.2
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• pp.105-110
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• 2015

Purpose: The purpose of this study was to evaluate the 3 dimensional accuracy of impression taking on the newly developed healing abutment and impression coping combined system comparing conventional pick-up type impression. Materials and methods: For 10 patients who had a single missing tooth on molar area, dental implants (SuperLine; Dentium, Seoul, Korea) were placed and healing abutment (MyHealing; Raphabio Co., Seoul, Korea) abutments were connected. After 3 months, transfer type impression with MyHealing and pick-up type impression with impression coping were performed twice in the same patients, and master models were fabricated. Customized prosthetic abutments (Myplant; Raphabio Co., Seoul, Korea) were milled and connected to the master casts. Through a dental scanner (Scanner S600; Zirkonzahn, South Tyrol, Italy), the master casts were converted into virtual casts. The length and angulation differences between casts were measured using 3 dimentional analysis program (Geomagic Qualify 12; Geomagic, Morrisville, NC, USA). Statistical significance was calculated using Kruskal Wallis test and Mann-Whitney U test (${\alpha}$=.05). Results: The length differences between the two systems were 0.032 mm in sagittal plane, and 0.029 in coronal plane, and 0.023 mm in horizontal plane. The angulation differences were $0.755^{\circ}$ in sagittal plane, and $1.275^{\circ}$ in coronal plane, and $0.420^{\circ}$ in horizontal plane. Conclusion: The accuracy of newly developed healing abutment system is similar to that of conventional pick-up impression. The new system can reduces chair time by not using separate impression coping.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.175-184
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• 2008

Purpose: This study was designed to investigate the fitness of adjustable dental impression trays on the Chinese and the Japanese. Material and methods: Initial design of the adjustable dental trays was developed from the results of the dental arch size of Korean adults. This design was applied to the CAD-CAM process in order to create tray model samples. Simple silicon-base molds were then replicated based on these sample models. Polyurethane injection into the silicon- base molds completed the process of creating a large number of test products. 60 Chinese dental students (male:30, female:30) from the Shanghai Second Medical University and 60 Japanese alumni from the Kumamoto high school (male:30, female:30) were selected for taking irreversible hydrocolloid impression with these trays. The width and length of the impression body were measured on several measuring points by Vernier caliper. The results were analyzed statistically to evaluate the fitness of the trays. Results: 1. Uniform impression material thickness was achieved on the Chinese and Japanese by controlling the width of the tray using stops and beveled guides. The material thickness was generally within the range of 3 mm to 6 mm. 2. In the maxillary tray of the Chinese, average thickness of the impression material of the labial vestibule of the incisal teeth was 6.2 mm, the canine was 5.9 mm and the midpalatal part 10.5 mm and the posterior palatal part 9.7 mm. These were relatively large values. 3. In the mandibular tray of the Chinese, average length of the impression material of the lingual vestibule of first, second premolar contact point was 8.9 mm, the incisal teeth was 7.8 mm and thickness of the labial part of canine was 6.8 mm and premolars 7.0 mm. These were relatively large values. 4. In the maxillary tray of the Japanese, average thickness of the impression material of the labial vestibule of the incisal teeth was 7.4 mm, the canine was 7.7 mm and the midpalatal part 9.1 mm. These were relatively large values. 5. In the mandibular tray of the Japanese, average thickness of the impression material of the labial vestibule of first, second premolar contact point was 8.4 mm, and thickness of the labial part of canine was 7.4 mm. These were relatively large values. Conclusion: This adjustable dental tray shows good accuracy to Korean because it was designed by the analysis of the dental arch size of Korean adult model. With this result, it can be applied to Chinese and Japanese, we can take more easy and accurate dental impressions.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.122-122
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• 2007

• Journal of dental hygiene science
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• v.6 no.4
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• pp.231-235
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• 2006

This study evaluated the properties of polyvinylsiloxane impression materials: Strain-in-compression, Elastic recovery, Consistency, and Wettability. Four polyvinylsiloxane impression materials(Examixfine, GC, Japan; Aquasilultra, Dentsply, USA; Extrude, Kerr, USA; Perfect-F, Handae, Korea) were used in this study. The measured data were analyzed with SPSSWIN 12.0 program. The results were as follows : 1. The strain-in-compression values showed that Extrude had the lowest value, 4.86% and Examixfine had the highest value, 6.78%. Significant difference between Examixfine and Perfect-F was not found but the other groups had significant differences(p = 0.000). 2. In the elastic recovery test, Extrude had the highest, 99.83% and Perfect-F had the lowest, 96.54%. There is no significant difference between Examixfine and Aquasilultra. The other impression material groups showed significant differences(p = 0.000). 3. The measurement of consistency results that the diameter of Examixfine was the largest, 45.12mm and one of Perfect-F was the smallest, 40.28 mm. No differences were shown between Examixfine and Aquasilultra and between Extrude and Perfect-F(p = 0.001). 4. Aquasilultra had a better hydrophilicity($47.85^{\circ}$) than other materials. Perfect-F had a larger contact angle($94.89^{\circ}$) and was hydrophobic. There were significant differences between groups(p = 0.000). 5. As for correlation among the test types, contact angle correlated with strain-in-compression, elstic recovery and consistency. The strain-in-compression had correlation to contact angle and elastic recovery. The elastic recovery correlated with contact angle and strain-in-compression. And the consistency had correlation to contact angle.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.94-100
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• 2014

The purpose of this study was to evaluate the accuracy of digitized elastomeric impression materials of crown abutment, using non-contact white light scanner and virtual three-dimensional superimpositional analysis. The stone models and impressions were digitized white light scanner to create three-dimensional surface models. Stone models were used as CAD reference model (CRM). The resulting point clouds (ASC file) from digitization of impressions using converting software. Discrepancies between the points in the point clouds and CRM were measured by superimpositional software. Mean and standard deviation of values of discrepancies were analyzed by one-way ANOVA and multiple comparison (${\alpha}=0.05$). The mean discrepancy between the impressions for the extra-light body (XLB), light body (LB), and heavy body (HB) group were $5.10{\pm}1.45{\mu}m$, $6.30{\pm}1.87{\mu}m$, $9.80{\pm}1.52{\mu}m$, respectively. The different impression materials affected the digitization of impressions significantly (p<0.05). As a result, digitization of elastomeric impression materials on dental scanner was influenced by material sort.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.2
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• pp.111-119
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• 2015

Purpose: The objective of this study was to evaluate the accuracy of a stereolithographic surgical guide that was made with information from intraoral digital impressions and cone beam CT (CBCT). Materials and methods: Six sets of resin maxilla and mandible models with missing teeth were used in this study. Intraoral digital impressions were made. The virtual models provided by these intraoral digital impressions and by the CBCT scan images of the resin models were used to create a surgical guide. Implant surgery was performed on the resin models using the surgical guide. After implant placement, the models were subjected to another CBCT scan to compare the planned and actual implant positions. Deviations in position, depth and axis between the planned and actual positions were measured for each implant. Results: The mean deviation of the insertion point and angulation were 0.28 mm and $0.26^{\circ}$, apex point were 0.11 mm and 0.14 mm respectively. The implants were situated at a mean of 0.44 mm coronal to the planned vertical position. Conclusion: This study demonstrates that stereolithographic surgical guides created without the use of impressions and stone models show promising accuracy in implant placement.