• Journal of Yeungnam Medical Science
• /
• v.11 no.2
• /
• pp.323-331
• /
• 1994

1,050 patients who visited orthodontic dental department from 1983 to 1994, were surveyed on the yearly tendency of orthodontic patient distribution and state by means of Angle's classification. The results were as follows: 1. There was increased visiting rate of patient per year and higher visiting rate in female than in male. 2. 8-15 age group was 61.4% in total visiting patients and over 20 age group was 18.5%, under 7 age group was 8.1% 3. Class I malocclusion was 42.2%, class II div 1 was 22.5%, class II-2 was 3.9%, class III was 29.1% and cleft lip & palate was 2.0% in total visiting patient. 4. As showed the living distribution, Namgu and Susunggu's patients were 43.7% of the total patients. 5. There was increased tendency for the number of the patient to be recieved orthognathic surgery.

• Archives of Craniofacial Surgery
• /
• v.13 no.2
• /
• pp.125-129
• /
• 2012

Purpose: Methylmethacrylate is the most commonly used alloplastic material in cranioplasty. However during the polymerization of methylmethacrylate, a significant exothermic reaction takes place. This reaction may result in thermal injury to the brain tissue and other soft tissues. Also it is difficult to make three-dimensional methylmethacrylate implant that is perfectly matched to the defect during the operation time. We report on the molding technique of methylmethacrylate implant using plaster mold and the rapid prototyping model in cranioplasty. Methods: A 44-year-old male was referred to the department for severe frontal hollowness. He was involved in an automobile accident resulting in large frontal bone defect with irregular margin. The preformed patient-specific methylmethacrylate implant was made using plaster mold and the rapid prototyping model before the operative day. The methylmethacrylate implant was placed in the frontal defect and rigidly fixed with miniplates and screws on the operative day. Results: The operation was performed in an hour. In the 6 months follow-up period, there were no complications. Patient was satisfied with the results of cranioplasty. Conclusion: Safe cranioplasty was performed with the preformed patient-specific methylmethacrylate implant using plaster mold and the rapid prototyping model. The result of this method was satisfactory, aesthetically and functionally.

• Journal of Conservation Science
• /
• v.12 no.1 s.15
• /
• pp.15-25
• /
• 2003

It is well known that the salt in stoneworks impact on damage of stone by various methods. Various kind of salt is detected in high content in the black surface layer of stone monuments and it is required about origin and roles of salts on blackening to considerate. In this study have been investigated the characteristics of salt in the black crust of sandstone and limestone which used in historical monuments in Berlin, Germany. Salt was analyzed for cation by Atomic Absorption and Atomic Emission Spectroscopy and for anion by ion Chromatograph. The representative ions are $Ca^{2+}\;and\;SO_4^{-2}$ in all samples and the most obvious combinations was proved in calcium sulfate by statistical methods. Because gypsum was detected by X-ray diffraction analyses in the black crusts, this calcium sulfate was confirmed by 2 hydrate type. The probable origin of Ca is air particle in atmosphere around sandstone and calcite in mother rock in limestone, and that of S is polluted air and mortar which used as conservation works.

• Journal of Conservation Science
• /
• v.27 no.4
• /
• pp.451-458
• /
• 2011

This study aims at identifying wall painting production technique of Songsanri No. 6 tomb based on optical examination and scientific analysis along with the investigation of written records of ancient wall paintings. The result displays that bricks with mortar were used for the construction of the wall, and masonry joint were made of lime, sand and gypsum. The surface of brick were plastered with black and thereafter with white lime. Finely sifted clay on the top of the white surface, were applied not with plasterer's trowel but with a brush for making ground surface. The clay are mineral particles smaller than $30{\mu}m$ of silt. The wall paintings of Sonsanri No. 6 is the only example of making ground layer with clay for painting of Sasindo (literally four heavenly animals painting) among remaining wall paintings of ancient tombs. The historical value of the painting should be attributed not only in terms that it displays a rare production techniques which were never discovered in any other paintings in Korea and Asia, but also it might had been uncompleted when the tomb were closed, even though it considers the fact that the wall painting were discovered in damaged condition in 1933.

• Economic and Environmental Geology
• /
• v.15 no.4
• /
• pp.205-219
• /
• 1982

The Eosangcheon manganese ore deposits occur as supergene weathering deposits along quartz porphyry dikes developed in the Ordovician Heungweolri dolomite and Samtaesan limestone formations. The manganese ores are composed of manganese oxide minerals and associated other minerals. Rancieite and todorokite are abundantly found, and birnessite, nsutite, pyrolusite and chalcophanite are found in minor quantities. Associated other minerals are calcite, gypsum, goethite, lepidocrosite, quartz, and sericite. Microscopic, chemical, X-ray powder diffraction, infrared absorption spectroscopic and differential thermal analyses have been made for manganese oxide minerals and associated other minerals. The relationship of birnessite and rancieite was studied by means of X-ray powder diffraction and infrared absorption spectroscopic analyses. It is assumed that these minerals are closely related to each other in crystal structure, but separate species. The manganese oxide minerals were formed mainly by replacement, precipitation from solution, and recrystallization in the supergene weathering environment. The trend of formation of manganese oxide minerals is: (Rhodochrosite)-(todorokite)-(birnessite, rancieite)-(nsutite, pyrolusite, chalcophanite).

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.4
• /
• pp.511-517
• /
• 2015

Sound absorption capability of the flame resistant treated sawdust-mandarin peel composite particleboard was were estimated by two microphone transfer function methods. The weight of flame resistant treated board slightly increased by the treatment. The treatment improved fire retardant performance by decreasing the charred area of flame resistant treated board. Sound absorption capabilities of flame resistant treated sawdust-mandarin peel composite particleboard, in the entire estimated frequency range of 500-6,400 Hz was slightly lower than those of the control specimen. Sound absorption capability of both the control and flame resistant treated sawdust-mandarin peel composite particleboards were higher than that of commercial gypsum boards, being widely used as a sound absorber for ceiling at the estimated frequency.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.1
• /
• pp.38-43
• /
• 2012

Sound absorption capability and mechanical properties such as MOE and MOR in bending of miscanthus particle based board were estimated by the two microphone transfer function method and three point bending method, respectively. The results are summarized as follows: The sound absorption coefficients of miscanthus particle based board was higher than those of commercial gypsum board which is well used as sound absorbing barrier. The MOR and MOE of miscanthus particle based board increased with increasing of board density. The sound absorption coefficients of miscanthus particle based board were 50~80% in the frequency range of about 1~2.5 Khz. In entire frequency range, those value increased with target board density decreasing.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.38 no.4
• /
• pp.289-296
• /
• 2012

Cosmetic products which might augment the breast have attracted an attention and objective methods for the evaluation of such products are in high demand. This study was conducted to establish a method for assessing the breast-firmming effects of cosmetics. This study included a total of 30 healthy Korean females aged 20-50 years. A cosmetic product was applied by massaging it onto the breast twice a day for 8 weeks. Measurement of breast girth with a tape ruler, 2D and 3D digital image analyses, and Moir$\acute{e}$ topographic analysis were performed before and following the treatment. The application of a cosmetic onto the breast significantly increased breast girth at 2, 4 and 8 weeks without a significant change in underbreast girth, implicating the breast might be augmented. The 2D image analysis indicated that the arc length of the breast which represents the surface distance from the nipple to the periphery of the under-breast was significantly increased at 2, 4 and 8 weeks. The height of the breast which represents the perpendicular distance from the nipple to the periphery of the under-breast was also increased significantly at 4 and 8 weeks. The 3D image analysis of body surface also demonstrated a significant increase of breast volume at 2, 4 and 8 weeks. Moir$\acute{e}$ topographic analysis indicated that breast sagging was significantly reduced at 2, 4 and 8 weeks. The results of this study suggest that Moir$\acute{e}$ topography in combination with 2D and 3D digital image analyses may be useful for evaluating the breast-augmenting effects of cosmetics.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.36 no.1
• /
• pp.29-40
• /
• 2020

Purpose: The purpose of this study was to compare the accuracy of impression taking method using the encoded healing abutment, scan body and pick-up impression coping with different implant angulations. Materials and Methods: Master model was fabricated by 3D printer and three implants were placed into the model with 0°, 10° and 20° mesial angulation. The abutments were secured to each implants and master model was scanned to make a reference model. Group P model was fabricated using pick-up impression copings and model was scanned after securing the abutments. Encoded healing abutment (Group E) and scan body (Group S) were secured on the master model and digital impression was taken using intraoral scanner 15 times each. Each STL files of test groups were superimposed with reference model using best fit alignment and root mean square (RMS) value was analyzed. Results: The RMS values were lowest in Group P, followed by Group S and Group E. Group P showed significant difference with Group S and E (P < 0.05) while there was no significant difference between Group S and E. Correlation between implant angulation and RMS value was significant in Group E (P < 0.05). Conclusion: The pick-up impression coping method showed higher accuracy and there was no significant difference in accuracy between the healing abutment and the scan body. The clinical use of the encoded healing abutment is possible, but it should be used with caution in the case of angulated implant.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.3
• /
• pp.359-366
• /
• 2010

It was easy to find that children of a skeletal anterior crossbite in the early mixed dentition period showed a stark difference in the dental maturity between their maxillary and mandibular teeth, if they have stronger physical characteristics. If the difference of dental age between maxillary and mandibular teeth which can be identified via panoramic radiographs may serve as an early sign of class III malocclusion, this is considered valuable as a tool of early detection diagnosis. We obtained lateral cephalometric radiographs, panoramic radiographs, working model and clinical images of patients of Hellman dental age IIA and IIC who visited the department of pediatric dentistry, Pusan National University Dental Hospital and examined them to select 50 patents for normal occlusion group and skeletal anterior crossbite group, respectively. Their panoramic radiographs were used for the Demirjian's method to figure out dental ages of maxillary and mandibular teeth of each group and the eruption rate of the first molars. Their differences are as follows: 1. In both groups, the dental ages from Demirjian's method were advanced than the chronological ages. No sexual dimorphism was detected for the chronological or dental age in either group (p>0.05). 2. The difference of dental age of maxillary and mandibular teeth between the normal occlusion group and crossbite group was 0.22 and 0.69 years, respectively, with a higher difference in crossbite group(p<0.05). 3. Compared to the normal occlusion group, the crossbite group showed a higher difference in the eruption rate between maxillary and mandibular first molar(p<0.05).