• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.6
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• pp.321-325
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• 2012

Collagen is widely used for regenerative therapy and pharmaceutical applications as one of the most useful scaffolds. Collagen is the most abundant protein in vertebrates and the natural substrate of various types of animal cells. Bone and dentin are mineralized tissues and almost similar in chemical components. They consist of collagen (18%), non-collagenous proteins (2%), hydroxyapatite (70%) and body fluid (10%) in weight volume. Pepsin-digested, type I collagen (atelocollagen) and heat-denatured collagen (gelatin) are basic collagenous materials for medical use. Demineralized dentin matrix (DDM) and demineralized bone matrix (DBM) belong to acid-insoluble group, and vital tooth-derived DDM is a unique dentin material including cementum and growth factors. In this review, collagen-based materials will be introduced and discussed for bone regenerative surgery.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.6 no.1
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• pp.18-31
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• 1997

By the concerns of esthetic restoration were increased recently. many all ceramic crowns were developed. But they except In-Ceram Alumina were used only single crown. In-Ceram Alumina, developed by Dr. Sadon, was revealed to have high flexural Strength(450MPa). So it could be used not only anterior bridges but also posterior bridges. But In-Ceram Alumina was seen to be opaque, a little green color in transillumination light by high content of alumina oxide(85%). So new all ceramics with high strength and high translucence were needed. Spinell($MgAl_2O_3$) have a high melting point, high flexural strength, low heat conductivity, high light conductivity. In-Ceram Spinell offers glasslike light transmission by using the spinell cores instead of the alumina cores. And they have a high translucency like to natural tooth, an excellent margin integrity and a high strength(350MPa). The purposes of this study are 1) to know about the construction method of In-Ceram Spinell System, 2) to investigate the its clinical possibiliy through patients and literature reviews.

• Journal of Korean Dental Science
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• v.9 no.1
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• pp.42-48
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• 2016

Prophylactic removal of impacted third molars is a common procedure in dentistry, but the necessity of routine extraction is still controversial. When impacted third molars caused severe apical root resorption of the second molars, orthodontic traction of the third molars after extraction of the damaged second molars could minimize alveolar bone defect and preserve the patient's natural teeth. By well-planned orthodontic treatment, functional occlusion was established avoiding extraction of the impacted teeth and eliminating the possibility of a large bone defect after extraction.

• The Journal of the Korean dental association
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• v.21 no.5 s.168
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• pp.415-423
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• 1983

A total of 202 full coverage crowns from 31 patients was investigated to find out the relationships between crown contour and gingival response. Every experimental crown has its contralateral natural tooth for its control group. Gingival Index and buccolingual width of the crowns were measured on both experimental and control group. Following conclusions were obtained from the study. 1. Most of the crown restorations were overcontoured and the increments were servere at cervical and height of contour area. 2. Height of contour and contact point of the restored crown were located near cervical area. Besides, most crowns had narrow embrasure with wide contact area. 3. Gingival Index around crown restorations was significantly larger than that of control group. 4. the interrelationship between Gingival Index and restored material or restored period was not verified at 5% significant level. 5. When grouping the artificial crowns into overcontoured, normal contoured, and undercontoured group by their width increment, the gingival inflammation was the severest in the overcontoured group and the mildest in the undercontoured group.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.23 no.2
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• pp.70-76
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• 2014

After extraction of tooth, alveolar ridge resorption is inevitable in most cases. Clinicians confront with horizontal and vertical resorption of alveolar bone. Without massive amount of bone and soft tissue graft, dental implant will be placed apically to gain stability. In those cases, not only white esthetic part, but also pink esthetic part should be restored with pink porcelain. The margin of prosthesis should be located apically to reproduce natural look with adjacent teeth. However, when the margin is located apically, it is always hard to remove remaining cement, thus complications may arise. In this report, a novel design of implant prosthesis is introduced to solve those issues. The novel design is consisted of zirconia framework with pink porcelain and separate crowns on top of the framework. It eliminates the possibility of cement remnants by bringing the crown margin coronally. Pink esthetic part is incorporated in abutment part instead of crown part and the screw hole is covered with separate crowns.

• Journal of Technologic Dentistry
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• v.6 no.1
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• pp.27-30
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• 1984

This investigation was performed to study the relationship of the dental midline(an imaginary line between the centeal incisors) to the philtrum. 2,400 subjects with natural dentitions were examined. The group of the subjects was composed of 1,560 men and 840 women who had all of the upper and lower six anteriors and 0 to 4 missing teeth. Ages of the subjects ranged from 18 to 27 years. The obtained results were as follow: 1. The rates of the subjects whose philtrum and maxillary dental midline coincided was 64.92% and that of the subjects whose upper and lower dental midlines coincided was 29.17%and these rates are statistically significant, when compared respectively with those of the subjects whose philtrum and maxillary dental midline, and whose upper and lower dental midline's didn't coincide. 2. The difference between rates for the two sexes is not statistically significant. 3. Tooth missing significantly decreases the rates of the coincidence of the upper and lower dental midlines but its influence on the rates of coincidence of the dental midline to the philtrum is not significant.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.13 no.1
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• pp.31-39
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• 2004

For the prosthodontic results which are compatible with esthetics to be fulfilled, the first prerequisite would be periodontal intervention and stability, the second one may be functional competency and the ultimate goal should be ascribed to esthetic considerations. Other words, esthetic dentistry is a whole entity which encompasses the biological stability of the periodontium, physical accuracy of the prosthodontic structure and finally, the beauty which can be found in natural dentition. It also implies the harmonized lip line which reveals the well-balanced tooth morphology and health gum profiles (Red-White Esthetics). Largely, there lie some differences in the input system of the 3-dimentional data from the prepared abutments between respective computer-assisted systems available now. But the manufacturing systems (CAM) are very similar between them, to say, comprise numeric control systems with whole 3-dimensional milling units according to the restorations to be made. Now the author is going to present CAD/CAM Zirconia All Ceramic Restoration on the topics for the Red-White Esthetics, periodontal control and maintenance, treatment for the discolored teeth, post & core build-up works for the devitalized teeth, characteristics of the Zirconium oxide All Ceramics, fabrication procedures, clinical considerations and its application to diverse clinical situations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.99-104
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• 1999

In this paper, dynamic behavior of a two stage gear train system is analyzed. This system consists of three shafts supported by ball bearing at the ends of them and two pairs of spur gear sets. For exact analysis, the meshing tooth pair of gears is modeled as spring having time-dependent meshing stiffness and damping. The result of this analysis is compared to that of analysis using other model of spring having mean mesh stiffness. The effect of the excitation force by the imbalance of a rotor of a motor on the vibration of a gear train system is also analyzed. Finally, the change of a natural frequency of the whole system due to the change of an angle between three shafts is compared in each case, and from this analysis, the avoiding angle for design is advised.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.135-138
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• 2001

This paper presents micro step driving method using VHDL(Very high speed integrated circuit Hardware Description Language) which can configure CPLD(Complex Programmable Logic Device). Using VHDL which can do abstractive programming is similar to high level language. The whole block divided into five parts with freq. divide part, saw-tooth wave generation part, sine-cosine wave generation part, comparative part, out part. In the result of this study, peripheral circuits are to be simple and using LPM(Library of Parameterized Modules) is more easily to configure circuit. It is easy to verify and implement by using VHDL. To subdivide one natural step, we confirm that using micro step driver is expected that the rotor motion is stepless very smooth.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.26 no.1
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• pp.39-51
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• 2017

In order to solve the problem of repositioning the old hader bar attachment and to restore the non-esthetic facial profile and improper occlusion of the edentulous patient due to inadequate jaw relation, determination of vertical dimension of occlusion and tooth arrangement were performed similar to the natural teeth before the teeth loss. In addition to improving the esthetics by restoring the inadequate facial appearance, the composite resin was used to maximize the patient's secondary esthetic satisfaction with the denture.