• Journal of Dental Rehabilitation and Applied Science
• /
• v.36 no.4
• /
• pp.242-253
• /
• 2020

Purpose: The aim of this study was to compare the accuracy of dies fabricated using 3D printing system to conventional method and to evaluate overall volumetric changes by arranging the superimposed surfaces. Materials and Methods: A mandibular right first molar from a dental model was prepared, scanned and fabricated with composites of polyetherketoneketone (PEKK). Master dies were classified into 4 groups. For the conventional method, the impression was taken with polyvinylsiloxane and the impression was poured with Type IV dental stone. For the 3D printing, the standard die was scanned and converted into models using three different 3D printers. Each of four methods was used to make 10 specimens. Scanned files were superimposed with the standard die by using 3D surface matching software. For statistical analysis, Kruskal-Wallis test and Mann-Whitney U test were done (P < 0.05). Results: Compared to the standard model, the volumetric changes of dies fabricated by each method were significantly different except the models fabricated by conventional method and 3D printer of Stereolithography (P < 0.05). The conventional dies showed the lowest volumetric change than 3D printed dies (P < 0.05). 3D printed dies fabricated by Stereolithography showed the lowest volumetric change among the different 3D printers (P < 0.05). Conclusion: The conventional dies were more accurate than 3D printed dies, though 3D printed dies were within clinically acceptable range. Thus, 3D printed dies can be used for fabricating restorations.

• The Journal of Korean Academy of Prosthodontics
• /
• v.62 no.1
• /
• pp.6-19
• /
• 2024

With the advancement of Computer-Aided Design/Computer-Aided Manufacturing (CAD-CAM) technology, fabrication of dentures using this technology has gained popularity. As one of CAD-CAM technologies, digital complete denture system has been introduced, which fabricates complete dentures using subtractive manufacturing of monolithic block containing both the color of a denture base and an artificial tooth. In this case, two pairs of upper and lower dentures were fabricated for two patients. Two pairs of complete dentures were fabricated for a 74-year-old male and a 73-year-old female respectively by conventional denture fabrication method and digital method of milling. To obtain a digital complete denture, monolithic block (Ivotion, Ivoclar Vivadent, Schaan, Liechtenstein) was chosen for the materials to fabricate the digital complete dentures. An individual tray was designed using CAD software and manufactured by 3D printing technique. The final impression and interocclusal relationship were recorded using the fabricated individual tray. The final impression was scanned, and the complete denture design and try-in denture were 3D printed using CAD-CAM software. Subsequently, the monolithic block was milled, and the final dentures were fabricated and tried on patients. Previously mentioned two patient cases compared and analyzed stability, fit, speaking, mastication, aesthetics, and patient satisfaction of two pairs of dentures: one fabricated using CAD-CAM system and the other using traditional methods. This was performed to evaluate and report the findings from both denture-making approaches.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.4
• /
• pp.546-554
• /
• 2007

Statement of problem: Die materials require abrasion resistance, dimensional stability with time, and high surface wettability for adequate material properties. Wear of gypsum materials is a significant problem in the fabrication of accurately fitting cast prosthetic devices. So It has been recommended that the use of die hardener before carving or burnishing of the wax pattern. Purpose: The purpose of this study was to compare the abrasion resistance and surface microhardness(Knoop) with 3 commonly used gypsum die materials(MG Crystal Rock, Super plumstone, GC $FUJIROCK^{(R)}$ EP) with and without the application of 2 die hardeners. Material and methods: Three die materials were evaluated for abrasion resistance and surface microhardness after application of 2 die hardeners(Die hardener and Stone die & plaster hardener). Thirty specimens of each gypsum material were fabricated using an impression of resin die(Pattern resin; GC Corporation, Japan) with 1-mm high ridges, sloped 90 degrees. Gypsum materials were mixed according to manufacturer's recommendations and allowed to set 24 hours before coating. Specimens were arbitrary assigned to 1 of 3 treatment subgroups (n=10/subgroup): no treatment(control), coated with Die hardener, and coated with Stone die & plaster hardener. Abrasion resistance(measured by weight loss) was evaluated using device in 50g mass perpendicular to the ridges. Knoop hardness was determined by loading each specimen face 5 times for 15 seconds with a force of 50g. A scanning electron microscope was used to evaluate the surface of specimens in each treatment subgroup. Conclusions: The obtained results were as follows: 1. 3 types of die stone evaluated in this study did not show significant differences in surface hardness and abrasive resistance(P<.05). 2. In the abrasive resistance test, there were no significant differences between GC $FUJIROCK^{(R)}$ EP and MG Crystal Rock with or without 2 die hardener(P<.05). 3. Super plumstone treated with Stone die & plaster hardener showed increased wear loss(P<.05) 4. Die hardener coatings used in this study decreased the surface hardness of the gypsum material(P<.05).

• (The) Research of the performance art and culture
• /
• no.36
• /
• pp.725-750
• /
• 2018

Uigue(儀軌) is the report of court events, and its contents are very detailed and crucial as it is even called as the flower of written culture. Thus, many research theses about Uigue have been accumulated in academic circles so far, and easy books about Uigue targeting ordinary people have also been published. However, Uigue has not been used actively in educational circles yet. From now on, we should develop and induce ways to use Uigue actively in educational spots in order to let students who will lead our future have pride in our culture and know about the superiority of our court music culture. Especially when court music culture is taught in the sector of Korean traditional music education, it is beneficial to use Uigue. Since most of the court music repertory is slow and magnificent, if court music itself is exposed beforehand, it might give them an impression that it is "unexciting and boring". Therefore, this study gropes for teaching methods to 'show' court music culture first through various visual aids contained in Uigue. In other words, it examines how the instrument images, band images, dance images, or concert stages contained in Uigue can be used as teaching materials. Except for the materials selected in this article, there are plenty of teaching materials for court music culture in Uigue. Furthermore, it would be even better if not just Uigue but Oryeseo (五禮書), Akseo(樂書), Dobyeong(圖屛), and Gwanchan Akbo(樂譜) can be added to widen its range for more multilateral court music culture education. And if at the educational spots, showing classic court music culture is accompanied with listening to court music through various materials of court music and dance, we can expect even better educational effects from it.

• The Journal of Korean Academy of Prosthodontics
• /
• v.51 no.4
• /
• pp.269-275
• /
• 2013

Purpose: The aim of this retrospective study was to evaluate the influence of implant diameter, length and placement to implant stability. Materials and methods: Total 90 implants (US II plus$^{TM}$, Osstem co, Busan, Korea) of 72 patients were determined as experimental samples. The factors of diameters(${\phi}$ 4 mm, ${\phi}$ 5 mm), lengths (10 mm, 11.5 mm, 13 mm), and implant placement (maxilla, mandible) were analyzed. The stability of the implants was measured by resonance frequency analysis (RFA) at the time of implant placement and impression taking. The difference of ISQ values according to patient's gender was evaluated by Independent t-test. ISQ values were compared between implant diameter, length and placement using one-way ANOVA and Tukey HSD test (${\alpha}=.05$). To compare ISQ values between at the time of surgery and impression taking, paired t-tests were used (${\alpha}=.05$). Results: The change of implant length did not show significant different on the ISQ value (P>.05). However, 5 mm diameter implants had higher ISQ values than 4 mm diameter implants (P<.05). Implants placed on the mandible showed significantly higher ISQ values than on the maxilla (P<.05). Conclusion: In order to increase implant stability, it is better to select the wider implant, and implants placed on mandible are possible to get higher stability than maxilla. ISQ values at impression taking showed higher implant stability than ISQ values at implant placement, it means that RFA is clinically effective method to evaluate the change of implant stability through the osseointegration. The consideration of the factors which may affect to the implant stability will help to determine the time of load applying and increase the implant success rate.

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.4
• /
• pp.243-250
• /
• 2010

Purpose: This study evaluated the effect of different screw tightening sequences and methods on detorque values in a well-fitting implant superstructure. Materials and methods: A fully edentulous mandibular master model and a metal framework directly connected to four parallel implants (Astra Tech) with a passive fit to each other were fabricated. Six stone casts were made with a splinted impression technique to represent a 'well-fitting' situation with the metal framework. Detorque values were measured twice after screw tightening using 20 Ncm. Detorque values and minimum detorque values for three screw tightening sequences (1-2-3-4, 2-4-3-1, and 2-3-1-4) and for two tightening methods (two-step and one-step) were analyzed using multi-way analysis of variance and two-way analysis of variance, respectively, at a .05 level of significance. Results: The mean detorque values for screw tightening sequences ranged from 12.8 Ncm (2-4-3-1) to 13.1 Ncm (2-3-1-4), and for screw tightening methods were 13.1 Ncm (two-step) and 11.8 Ncm (one-step). The mean of mimimum detorque values for screw tightening sequences were 11.1 Ncm (1-2-3-4) and 11.2 Ncm (2-4-3-1 and 2-3-1-4), and for screw tightening methods were 11.2 Ncm (two-step) and 9.9 Ncm (one-step). No statistically significant differences among three screw tightening sequences were found for detorque values and for mimimum detorque values. But, statistically significant differences between two screw tightening methods were found for two values. Two-step screw tightening method showed higher detorque value (P = .0003) and higher minimum detorque value (P = .0035) than one-step method. Conclusion: Within the limitations of this study, the screw tightening sequence was not a critical factor for the detorque values in a well-fitting implant superstructure by the splinted impression technique. But, two-step screw tightening method showed greater detorque values than one-step method.

• Restorative Dentistry and Endodontics
• /
• v.19 no.2
• /
• pp.641-654
• /
• 1994

This study was executed to evaluate adaptability of dentin bonding agents to dentinal wall with measuring contraction gap on interface between cavity wall and composite resin by SEM study. 6 kinds of dentin bonding agents were investigated for this study : Gluma, Super Bond C & B, All bond 2, Scotchbond multipurpose, Scotchbond 2 and Clearfil photo bond. 30 of fresh extracted teeth were randomly selected and divided into 6 groups with each 5. The round shaped cavities with 3mm dia. and 1.5mm depth were prepared on cementoenamel junction of buccal surface of teeth. Dentin bonding agents were applied to cavity wall and then the composite resin was filled in the cavity. Specimens were sectioned longitudinally on buccal surface. Sectioned aspects of specimens were impressioned with rubber base materials and finally precise replica were made of epoxy resin poured in negative impression. Contraction gaps were examined on interface between cavity wall and composite resin under condition of 200 and 2000 magnification of SEM. The results were as follows. 1. There were no gap on interface between enamel and composite resin in all specimens, but gaps were mainly exhibited on apical side of lateral wall of dentin of cavity. 2. In Gluma, 2 cases of 5 specimens exhibited excellent adaptation to the cavity wall, indicating no gaps on interface between cavity wall and composite resin. The other specimens showed gaps with range of $0{\sim}15{\mu}m$ width. 3. In Super Bond C & B, gaps with range of $0{\sim}10{\mu}m$ width were mainly exhibited on apical side of lateral wall of dentin of cavity. 4. In All bond 2, all specimens showed the most exellent adaptation to cavity wall when compared to the other materials, indicating no gap interface between cavity wall and composite resin. 5. In Scotchbond multipurpose, gaps with range of $0{\sim}10{\mu}m$ width were locally located on cavity wall. 6. In Scotchbond 2, all specimens showed great amount of gap with range of $5{\sim}25{\mu}m$, indicating the worst adaptation to cavity wall compared to the other materials. 7. In Clearfil photo bond, 2 case of 5 specimens exhibited exellent adaptation to cavity wall, indicating no gap. the other specimens showed gap with range of $0{\sim}15{\mu}m$ width on inferface between cavity wall and composite resin.

• The Korean Fashion and Textile Research Journal
• /
• v.14 no.5
• /
• pp.739-748
• /
• 2012

Modern people gratify their self-satisfaction to express their distinctive image and symbolic significance through various and sensible direction. The image that is formed by each factor of coordination and harmony of aesthetic characteristic has emphasized its importance in modern society. And also, the item which is conflated by the wearer's feeling figures the image and it takes a role that lifts the degree of fashion's completion. For the rapid change of fashion trend in modern society, the role of Jewelry has been emphasized. Even though the shape of Jewelry is tiny, but it has risen as one of the fashion items which could be used for various application. Especially, the Brooches are mainly put on her's top where they hold someone's eyes, so it could be regard as Artwork which assists for wearer's distinctive style and lingering impression. Overviews of Researches Trend in Brooch, they have been concerned about Brooch Design, Internal state of the Accessory in clothes and Accessory Design which is expressed in Fashion. But, the study on the relations between Clothes and Brooch is insufficient. So, in this paper, first of all we arrange the terms according to characteristic of Brooch, and then study empirically for the relations between Clothes and Shape of Brooch, Colors of Brooch, Materials of Brooch in Fashion Collection in order to study for the new physical beauty that is expressed by interaction between Clothes and Brooch.

• The Research Journal of the Costume Culture
• /
• v.24 no.5
• /
• pp.670-686
• /
• 2016

The purpose of this study is to delineate and analyze the expression of the kidult and its characteristics and thereby provide data to be used for fashion design in various manners as well as to suggest creative and varied possibilities of fashion design. As a way to study, the author of this paper organized the general terms, concepts and definitions concerning the kidult in the previous papers and journals. The data was collected from the collections represent the characteristics of kidult especially from 2006 to 2015. The results are as follows: Firstly, The characters stimulating the innocence of children were used the most for infantile expression. Parody used characters in the movie or famous logos. Deformation was used to create designs by way of distortion and deformation. Exaggeration thereby showing visually strong impression and inducing surprise and unexpectedness. Depaysement was useful to let us describe concepts and enhance our infinite creativity and interests about objects using surrealistic. Secondly, Infantile characteristics used the images of toys with infantile imagination and sense of humor. Fantasy introduced objects or expressed a dream-like feeling. Unexpectedness used two-faced ideas or conflicting ideas to express conflicts, collision and an interchange with heterogeneous things, avoiding the limit of size and the simplicity of materials. Parody used jocular expressions, satire and ironic expressions to express the original image in a fun manner. Exaggeration transformed changed the structure to restructure objects in a subjective and creative manner, thereby expressing creative patterns using various subject matters by way of special modeling or distortion and transformation.

• The Journal of Advanced Prosthodontics
• /
• v.9 no.2
• /
• pp.93-98
• /
• 2017

PURPOSE. The purpose of this study was to compare the width ratio of maxillary anterior teeth according to age in the Korean population and to evaluate the maxillary central incisor width-to-length (W/L) ratio, given differences in age and gender. MATERIALS AND METHODS. Ninety-three Korean adults were divided into 3 groups (n = 31) by age. Group I was 20 - 39 years old, Group II was 40 - 59 years old, and Group III was over 60 years of age. After taking an impression and a cast model of the maxillary arch, the anterior teeth width ratio and central incisor W/L ratio were calculated from standard digital images of the cast models using a graph paper with a digital single lens reflex (DSLR) camera. The calculated ratios were compared among all groups and central incisor W/L ratio were analyzed according to age and gender. All comparative data were statistically analyzed with one-sample t-tests, one-way ANOVAs with Tukey tests, and independent t-tests. RESULTS. No significant differences in maxillary anterior teeth ratios were found among the age groups. The maxillary central incisor W/L ratios in Group III were the greatest and were significantly higher than those in the other groups. The central incisor W/L ratio of men was higher than that of women in Group II. CONCLUSION. Maxillary anterior teeth width ratios were similar in all age groups in the Korean population. The maxillary central incisor was observed as worn teeth in the group over 60 years of age, and a significant difference between genders was found in 40 to 50 year olds.