• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.601-609
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• 1998

The objects of this study were to analyze the crown angulation, crown inclination, molar offset angle, and crown in and out of the Korean adults having normal occlusion. 14 subjects (7 male, 7 female) were chosen in the 80 subjects who had ideal occlusion and beautiful profile we thought. The casts were obtained from the subjects, and then they were scanned with 3-dimensional scanner machine. We analyzed them with computer program based upon Andrews methods and the following results were obtained. 1. We got the norm of the crown angulation, crown inclination, molar offset angle, and crown in and out in the Korean adults. 2. The analysis using 3 dimensional scanner and computer program was more fast and accurate than the manual methods.

• Journal of Technologic Dentistry
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• v.29 no.2
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• pp.79-85
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• 2007

In this study, We tried to find out the fracture strength of zirconia coping all ceramic crown and collarless porcelain fused gold alloy crown as the compared group. Each of the collarless porcelain fused gold crown and zirconia all ceramic crown has been produced specimen 10 each. And after pasting them on the steel jig, it had load given at porcelain incisal edge by 130$^{\circ}$ and measured fracture strength by Universal Testing Machine and then We have results from that. 1. The average value of fracture strength suggested 950.49 N at collarless porcelain fused gold alloy crown, 656.81 N at zirconia coping all ceramic crown. 2. Fractured pattern showed that the whole of labial part was exposed in collarless porcelain fused gold crown, but porcelain of margin part did not show fracture in advance. In the practice, the concern that collarless might cause fracture strength to be weaken does not matter, we concluded zirconia all ceramic crown made fracture that only a part of labial porcelain was fractured. The combination of zirconia all ceramic crown and turned out to be excellent.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.295-301
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• 2013

The author experienced 8 cases of pericoronal radiolucency involving an incomplete tooth crown that had not developed to form the cemento-enamel junction, and the underdeveloped crown sometimes appeared to be floating within the radiolucency radiographically. The first impression was that these cystic lesions had odontogenic keratocysts, but half of them turned out to be dentigerous cysts histopathologically. There has been no report concerning odontogenic cysts involving an incompletely developed crown. The purpose of this paper is to report that dentigerous cysts may develop before the completion of the cemento-enamel junction of a developing crown.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.115-121
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• 1999

This investing was carried out to evaluate the alteration of stress distribution on teeth and esthetic crowns. Analyzing the stress distribution by the two-dimensional finite element methods, a model of lower 1st molar according to the porcelain fused metal crown an the porcelain fused glass ceramic core crown and the all glass ceramic crown. 1. The pattern of stress distribution showed no apparent differences. 2. The greatest von Mises values were concentrated around the central fossa of all esthetic crowns. The greatest Maximum principle value were concentrated around the interface between the base of esthetic crown and the abutment tooth. It was found that the apatite glass ceramic could be applicable for use in dental crown prosthesis.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.925-933
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• 2009

This research was carried out by analyzing a form and composition in baseball cap targeting 97 marketing products, and we have typified it by frequency analysis. We have carried out comparing and wearing test between comparative pattern and the most preferred three products of sports brand, fashion brand A, and fashion brand B (flex fit). And also, in order to provide basic indices for developing new pattern, we have carried out analysis of variance. 1. As a result of analyzing a form in baseball cap, the most general pattern type for crown is central cutting with six pieces. In a cap, a basic type with no decoration was the most general. In the size adjustment and decoration, belt type and embroidery type (front or side embroidery of the crown) was the most common, respectively. 2. As a result of comparing and analyzing six-piece typed crown pattern, the comparative pattern was the same and symmetric in size and form of three patterns in front, side, and back. However, the patterns of marketing products of three brands were different in size and form of three patterns in front, side, and back. The patterns of sports brand were the largest in crown height and width, thus it was good at providing activity and motion. The patterns of fashion brand A were the shortest in the crown length and well-curved in front pattern, so it was well-matched with head shape. The patterns of fashion brand B were well-described back side of head since its convex and long patterns in the back head. 3. As a result of wearing test by five-point Likert scale among brand, pattern of fashion brand B outperformed the others since it was well-matched with head shape. In the cap, pattern of fashion brand A is the most preferred which was 7.5 cm of length and 18cm of width.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.200-210
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• 2002

In twin roll strip casting process, coupled analyses of heat transfer and deformation for the cast roll are carried out by using the finite element program MARC to examine the thermal crown. Shrink fit effect and plastic deformation are considered. The results shows that the thermal crown is greatly influenced by shrink ft and that the thermal crown for POSCO Pilot Caster 2 Copper Roll has “M” shape. The effects of several factors on thermal crown are also investigated. The amount of thermal crown increases as heat flux, casting speed, steeve thickness and casting roll width increase and decreases as the casting roll diameter increases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.193-197
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• 1982

1t is well known that the stem is filed with shoot units in the rice plant and each internode bears several crown roots. But it has not yet been ascertained that what controls the differential elongation of the crown roots in the same internode. Thereupon, author had been carried out this experiment to ascertain what controls the elongation of the crown roots in the same internode, especially on the conception of sink-source by leaf-cutting method. Generally, one shoot unit has two important sinks: one axillary bud (tiller) and several crown roots. When we removed the axillary bud, namely shoot unit has one sink: several crown roots, the crown roots formed near the midvein (source) were longer than the crown roots born near the axillary bud. And when the shoot unit has two sinks: one axillary bud and several crown roots, the other way, the crown roots formed at the prophyll unit of the tiller were longest, and the crown roots formed near the midvein were shortest and the crown roots born the near the tiller showed interim length. Juding from the present results, we can suppose that, when shoot unit has two sinks, axillary bud is superior sink than the crown roots. So that axillary bud grows faster than crown roots and tiller becomes a new source. Therefore the crown roots which formed at the new source and the crown roots born the near the new source are longer than others.

• Fibers and Polymers
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• v.3 no.2
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• pp.49-54
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• 2002

Radical copolymerization behavior of 4'-vinylbenzo-15-crown-5, a vinyl monomer having a pendant 15-membared crown ether unit (VCE) with di(ethylene glycol) ethyl ether acrylate (DEGEEA) was carried out in toluene solution using 2,2-azobisisobutyronitrile (AIBN) as an initiator. The copolymers were characterized by means of FT-IR, $^1{H-NMR}$, and $^{13}{C-NMR}$ . The reactivity ratio of VCE and DEGEEA, determined by Fineman-Ross and Kelen-Tudos method, gave values 0.55 for VCE, and 0.11 for DEGEEA respectively.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.2
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• pp.101-111
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• 2002

The purpose of this study was to evaluate the fracture strength of porcelain fused to gold crown and gold electroformed crown according to incisal and incisal under 3mm. In this study, 28 gold electroformed crown and 28 porcelain fused to gold crown were fabricated. Fracture strength testing was carried out using an Instron 8871(Instron Corporation, U.S.A) at a cross head speed of 5mm/min. All of the measurements were statistically analyzed by Independent t-testing, and k-s testing. Statistical significance was set in advance at the probability level of less than 0.05. All measurements were analized with Windows $SPSS^{(R)}$ Version 10.0 software for the personal computer. The results of this study were as follows; 1. Comparison by location (1) A compared fracture strength of incisal and incisal under 3 mm, there was statistical significant difference between gold electro -formed crown and porcelain fused to gold crown (p<0.05). 2. Comparison by loading (1) When compared fracture strength of incisal, there was no significant difference between gold electroformed crown ($619.90{\pm}53.54N$)and porcelain fused to gold crown($674.68{\pm}87.42N$). (2) When compared fracture strength of incisal under 3 mm, there was significant difference between gold electroformed crown($688.29{\pm}14.88N$) and porcelain fused to gold crown($1931.81{\pm}29.64N$) (p<0.05). 3. Mode of fracture When compared of fracture mode, gold electroformed crown showed mode of fracture and fracture line reaching coping region and porcelain fused to gold crown showed only in porcelain region.

• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.131-136
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• 2016

PURPOSE. The aim of this study was to observe stress concentration in the implant, the surrounding bone, and other components under the pull-out force during the crown removal. MATERIALS AND METHODS. Two 3-dimensional models of implant-supported conventional metal ceramic crowns were digitally constructed. One model was designed as a vertically placed implant ($3.7mm{\times}10mm$) with a straight abutment, and the other model was designed as a 30-degree inclined implant ($3.7mm{\times}10mm$) with an angled abutment. A pull-out force of 40 N was applied to the crown. The stress values were calculated within the dental implant, the abutment, the abutment screw, and the surrounding bone. RESULTS. The highest stress concentration was observed at the coronal portion of the straight implant (9.29 MPa). The stress concentrations at the cortical bone were lower than at the implants, and maximum stress concentration in bone structure was 1.73 MPa. At the abutment screws, the stress concentration levels were similiar (3.09 MPa and 3.44 MPa), but the localizations were different. The stress at the angled abutment was higher than the stress at the straight abutment. CONCLUSION. The pull-out force, applied during a crown removal, did not show an evident effect in bone structure. The higher stress concentrations were mostly observed at the implant and the abutment collar. In addition, the abutment screw, which is the weakest part of an implant system, also showed stress concentrations. Implant angulation affected the stress concentration levels and localizations. CLINICAL IMPLICATIONS. These results will help clinicians understand the mechanical behavior of cement-retained implant-supported crowns during crown retrieval.