• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.504-509
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• 1994

Achondroplasia is characterized by undergrowth of long bones and cartilages and by low height. The name of this disease had been called classical chondrodystrophy, dyschondroplasia, chondrodystrophy and micromelia before Parrot reported the term of this disease as Achondroplasia. We are reporting in this paper on an 3-year and 4-month-old boy with achondroplasia. The dental findings are as follows: 1. Open bite and relatively mandibular prognathism were observed in the front teeth. 2. The size, number, shape, structure of the teeth were usual and the tongue was a little bigger than the normal. 3. The metacarpal bones were short and broadening. Mesial, distal border of the prox. phalanges were irregular and also trabecular pattern was abnormal in the hand-wrist P-A view. 4. According to lat. cephalometric analysis, the cranial basis was underdeveloped.

• Restorative Dentistry and Endodontics
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• v.2 no.1
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• pp.27-31
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• 1976

Eighty mandibular first premolars were injected with china ink, decalcified, cleared and used in an in vitro study to determine the number of root canals, the frequency and location of lateral canals, the location of apical foramens, the frequency of apical deltas, and the curvature of root canals. The results were as follows: 1. Most of the teeth demonstrated single canal, but 22.5% of the teeth were found to have bifurcated or trifurcated canals. 2. Of the 99 canals studied, 37.3% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. 27 apical foramens were located directly on the root apex and 66 foramens laterally. 4. 6 canals showed mesial curvature, 49 canals distal curvature, 11 canals buccal curvature, and 25 canals lingual curvature.

• The Korean Journal of Zoology
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• v.7 no.1
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• pp.6-8
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• 1964

1. A total of 260 individuals of carp was collected from Nakdong and Hyungsan Rivers. 2. The normal dental form of carp is 3, 1, 1-1, 1, 3, but the author observed abnormal dental forms (3, 2 or 1, 1, (+1)-1, 1 or 2, 3). 3. Variation ratios of dental forms are : A. Normal form; 3, 1, 1-1, 1, 3..........88.85% B. Abnormal forms; a. 3, 2, 1-1, 1 or 2, 3..........2.31% b. 3, 1, 1, 1-1, 1 or 2, 3..........5.00% c. 3, 2, 1, 1-1, 1 or 2, 3..........3.07% d. with 2 or 3 bone processes..........0.77% 4. The ratios among the length of first row (I), length of second tooth in first row ($I_{-2}$) and mid line(M) are as follows; 5. The growth of bone process beside second row tooth is not concerned with the body growth. 6. The number of the groove on second tooth in first row increases according to the growth of body.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.108-111
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• 2002

It is important to predict forming procedure for minimizing trial-and-error in the application of cold forging of gears. In this study, 3-dimensional simulations of cold forging processes of spur and bevel gear were carried out using finite element method to investigate the characteristics of the processes. From the simulation result it was found that incomplete teeth forming of spur gear was occurred with increase of teeth number in forging by forward extrusion. It can be reduced through division of material flows at the initial forming state using forward/backward combined extrusion.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.83-86
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• 1980

Fifty human maxillary second molars were injected with china ink, decalcified, cleared, and used in vitro study to determine the number of root canals, the frequency and location of lateral canals, canals per root, and frequency of apical deltas. The results were as follows. 1. The mesiobuccal root was found to contain a single primary canal in 62% of the teeth studied and two canals in 38% of the teeth studied. 2. In mesiobuccal roots with two canals, the seperated apical foramen appeared 24% of the specimens and the common apical foramen 14% of the specimens. 3. Of the 169 canals studied, 23.1% of the canals were found to contain lateral canals and these ramifications were mainly located in the apical third of the root.

• Tribology and Lubricants
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• v.24 no.5
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• pp.221-227
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• 2008

This paper presents a step-by-step design of noncircular gears. From the diagram of angular velocity ratio of a noncircular gear pair, the pitch curves of the two mating gears are determined, and the perimeter of the pitch curve has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. A noncircular gear pair has been designed by imposing the master tooth on the divided points of the pitch curve, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of the noncircular gear is a composite curve of arcs only, and consequently NC codes for wire EDM can be easily generated.

• Tribology and Lubricants
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• v.23 no.4
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• pp.149-155
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• 2007

The CAD model of a elliptical gear for wire cutting has been developed. The rolling contact of pitch ellipses whose rotation axes coincide with their focus has been analyzed, and the perimeter of the pitch ellipse has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. The elliptical gear has been designed by imposing the master tooth on the divided points of the pitch ellipse, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of an elliptical gear is a composite curve of arcs only, and consequently NC codes for wire cutting can be easily generated. Furthermore, a computer simulation program is developed to verify the mesh of the elliptical gear.

• Restorative Dentistry and Endodontics
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• v.15 no.2
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• pp.115-121
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• 1990

Forty extracted human mandibular second molars with C-shaped canal were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified and cleared with Winter green oil, in vitro, to study the number of root, root canal, canal per root, frequency and location of lateral canal and transverse anastomosis. 1. All teedth had one root. 2. Mesial roots with two canals were 25%, and mesial roots with one canal were 75%. All distal roots had one canal. 3. In the roots with two canals, the common apical foramen appeared in 20% and the separte apical foramen appeared in 80%. 4. The frequence of lateral canal was 33.3% and the most frequent region was middle 1/3. 5. All teeth had the transverse anastomosis in all region of the roots.

• The Journal of the Korean dental association
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• v.48 no.1
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• pp.56-62
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• 2010

In recent years, a number of special treatment procedures have been introduced to reestablish new tooth supporting tissues with varying degrees of success including guided tissue regeneration(GTR), bone grafting(BG) and the use of enamel matrix derivative(EMD). EMD is an extract of enamel matrix and contains amelogenins of various molecular weights. Emdogain(EMD) might have some advantages over other methods of regenerating the tissue supporting teeth lost by gum disease, such as less postoperative complications. Emdogain contains proteins(derived from developing pig teeth) believed to regenerate tooth attachment. The decrease in probing depth after EMD treatment is achieved primarily by clinical attachment gain and bone regeneration and only to a minor extent by gingival recession. In conclsion, EMD seems to be safe, was able to regenerate lost periodontal tissues in previously diseased sites based on clinical parameters.

• Animal Systematics, Evolution and Diversity
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• v.29 no.1
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• pp.84-91
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• 2013

Two species of the hippolytid shrimps, Lebbeus speciosus and Lebbeus comanthi, are described and illustrated for the first time in Korea. They were collected from the East Sea. Lebbeus speciosus was found in a scallop farm of Jumunjin, Gangneung, and L. comanthi associated with crinoids, was found in Gampo, Gyeongju. The difference between these two related species is in the number of dorsal teeth of the rostrum, five teeth in L. speciosus and a single tooth in L. comanthi. The Korean Lebbeus species has increased to 6 species by the present report. They are L. grandimana, L. polaris, L. unalaskensis, L. groenlandicus, L. speciosus, and L. comanthi.