• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.284-292
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• 2023

Stable posterior occlusal support is crucial for adequate masticatory function and facial aesthetics. In elderly patients over the age of 65, masticatory ability has a significant impact on nutritional intake and overall health. This case report presents a prosthetic treatment of an elderly patient with edentulous maxilla and bilateral posterior edentulous mandible. The upper jaw was restored with a complete denture to establish an ideal occlusal plane, and the three-dimensional positions of the mandibular implants were determined accordingly. The implants were placed through computer-guided implant surgery and were immediately loaded with fixed provisional restorations. The implant-fixed zirconia final restorations were inserted in the lower posterior region, and the occlusal surface of posterior artificial teeth in the upper denture was substituted with cobalt-chrome alloy to resist occlusal wear. The patient's posterior occlusal support and masticatory function were promptly restored through this treatment process, and long-term stability against wear was also obtained.

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.349-358
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• 2003

The success of dental implant therapy relies mainly upon the presence and maintenance of bone adjacent to implant. An 1-year prospective study was performed, upon the patients who were diagnosed as having chronic adult periodontitis, and had been treated with dental implant. The purpose of this study was to measure the radiographic bone level changes proximal to Astra Tech Single Tooth Implants (ATST, Astra Tech AB, $M{\"{o}}lndal$, Sweden) with microthread and Astra Tech TiOblast Implant (ATTB) without microthread supporting fixed partial prosthesis. Measurements were used to determine mean marginal bone loss during the first year of loading, 17 subjects with its partial prosthesis supported by 37 implants were followed up for an 1-year period. The marginal bone loss of implants was positively correlated with the retention factor, microthread($Microthread^{TM}$) in crestal area of ATST. The results were as follows. 1. The mean marginal bone loss of ATST was 0.226${\pm}$0.395mm, while ATTB was 0.440${\pm}$0.360mm. There was a statistically significant difference between ATST and ATTB (p<0.05). 2. The mean bone loss of the upper jaw fixtures was 0.269${\pm}$0.265mm for ATST and 0.529${\pm}$0.417mm for ATTB . There was a statistically significant difference between ATST and ATTB (p<0.05). In the lower jaw the corresponding figures were 0.167${\pm}$0.231mm and 0.313${\pm}$0.214mm, respectively. There was no significant difference between ATST and ATTB (p>0.05). 3. The mean bone loss of ATST was lower than that of ATTB at all sites according to bone quality. There was a statistically significant difference between ATST and ATTB at bone quality type III(p <0.05). In conclusion, the mean bone loss of ATST was smaller than that of ATTB . Therefore, the retention factor of crestal area, microthread ($Microthread^{TM}$) was effective to maintenance of marginal bone level around fixture.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.5
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• pp.447-453
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• 2010

The hemifacial microsomia is characterized by variable underdevelopment of the craniofacial skeleton, external ear, and facial soft tissues. So, patients with hemifacial microsomia have an occlusal plane canting and malocclusion with facial asymmetry. Distraction osteogenesis (DO) with an intraoral or extraoral device is a technique using tension to generate new bone with gradual bone movement and remodeling. DO has especially been used to correct craniofacial deformities such as a hemifacial microsomia, facial asymmetry, and mandible defect that could not adequately be treated by conventional reconstruction with osteotomies. It has a significant advantage to lengthen soft and hard tissue of underdeveloped site without bone graft and a few complication such as nerve injury or muscle contracture. A 13-years old girl visited our clinic for the chief complaint of facial asymmetry. She had a left hypoplastic maxilla and mandible, occlusal plane canting and malocclusion. We diagnosed hemifacial microsomia and lanned DO to lengthen the affected side. Le Fort I osteotomy, left mandibular ramus and symphysis osteotomy were performed. The internal distraction devices fixed with screw on maxillary and mandibular ramus osteotomy sites. External devices were adapted to lower jaw for DO on symphysis osteotomy site and to upper jaw for rapid maxillary expansion (RME). At 7days after surgery, distraction was started at the rate of 1mm per day for 13days, and after 4months consolidation periods, distraction devices were removed. Simultaneous multiple maxillo-mandibular distraction osteogenesis with RME resulted in a satisfactory success in correcting facial asymmetry as well as occlusal plane canting for our hemifacial microsomia.

• Korean Journal of Ichthyology
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• v.8 no.1
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• pp.83-89
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• 1996

The early life history of Korean bullhead, Pseudobagrus fulvidraco was studied to obtain some information required in aquaculture and reinforcement of natural population. The fertilized eggs were almost spherical in shape and demersal. The egg membranes were transparent with minute folds on the surface, causing them to stick to other substrates. Yolk is yellowish without oil droplets. The eggs just after fertilization were measuring $1.4{\pm}0.03mm$(1.3~1.5mm, n=10) and expanded to $1.7{\pm}0.08mm$(1.6~1.8mm, n=10) in diameter in 1.5 hr. The blastodisc was formed in 30 min and cleavage started in 1 hr after fertilization, and the intervals of each stage of cleavage was about 30 min at $25.0^{\circ}C$. The yolk from 32-cell stage to gastrula stage partly depressed and the depressed part moved clockwise. Hatching occurred in 53 hr after fertilization and hatched embryos had 18~19+20~21(38~40) myomeres measuring 4.2~4.3mm in total length. At the age 7 d after hatching, 4 pairs of barbels were already formed ; 1 pair on the posterior part of the nostril, 1 pair on the upper jaw, and 2 pairs on the lower jaw. And the posterior margin of caudal fin changed into two folds. The lateral band and the form of all fins were completed in 3 weeks.

• Korean Journal of Ichthyology
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• v.27 no.3
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• pp.189-198
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• 2015

This research has been launched in order to observe the osteological development of sevenband grouper, Epinephelus septemfasciatus larvae and juveniles and will be used for the basic data of phylogenetically systematics research. We got some samples of larvae and juveniles from a adult fish which belongs to the sea cage in Geomun-do, Yeosu-si, Jeolla-namdo province, and we have watched them. The average of breeding water temperature was $21.5{\sim}24.5^{\circ}C$ (average $23.0{\pm}1.5^{\circ}C$). In yolk-sac larvae just after hatching, ossification was not observed at all, and when the average total length reached 2.66 mm, the premaxillary and maxillary forming the upper jaw, dentary forming the lower jaw, and parasphenoid forming the skull base were ossified. In addition, the preopercle and opercle forming the opercular region began to be ossified. The caudal skeleton supporting the caudal fin is built with the caudal complex consisting of the malleus and incus. Until the average total length reached 2.59 mm, ossification did not occur at all and the urostyle bent at 45-degree angle. As to the ossification of the pterygiophore, when the average total length was 6.12 mm, the first interhemal spine began to be ossified in articulation with two spines of the anal fin, and the synapse also began to be ossified in articulation with two spines of the dorsal fin. When the average total length was 21.9 mm, individuals with completed ossification of the interhemal spines and synaptic clefts began to appear.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.241-265
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• 1989

The purpose of present study is to describe the taxonomy and early life history of Korean pomfrets, genus Pampus. Egg diameter varied from $0.83\~1.27mm\;and\;1.05\~1.41mm$ in P. argenteus and P. echinogaster respectively. Larvae of P. echinogaster of 16.5 mm in total length has full number of fin rays and enter the juvenile period. The egg is matured at 185.0 mm in total length in P. argenteus and at 95.5 mm in total length in P. echinogaster. P. echinogaster is ossified from jaw bone at $8.5\~10.0mm$ in to1 length and followed by ossification of vertebrae and visceral skeleton. P. argenteus and P. echinogaster are distinguished by the morphology of jaw, fin and isthmus. In P. argenteus, wavy ridges extends over the upper part of pectoral fin and gill membrane is broadly united to isthmus, while in P. echinogaster the ridges are limited to the base of pectoral fin and gill membrane reaching isthmus. These Pampus spp. are easily distinguished based on internal features, such as number of vertebrae, gill raker, pyloric caeca, epipleural bone, esophageal sat and length of intestine.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.258-272
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• 1998

This investigation evaluated patients who received Steri-Oss implants from the Dental Hospital of Chosun University during the period from March 1989 to August 1997. 346 fixtures of 127 patients were included in this study. The results were as follows ; 1.The follow-up period was defined as the period between the surgical placement of the implants and the last follow-up examination. The mean follow-up period was $2.17{\pm}1.21$ years. 2.The period between fixture installation and second surgery was $0.71{\pm}0.44$ years in the maxilla and $0.46{\pm}0.21$ years in the mandible. 3.The number of fixtures which were installed in the upper jaw(112) was less than that in the lower jaw(234) and in the posterior region(260) was more than in the anterior region(86). 4.The length of fixture which was most frequently used was 12 mm and least was 8mm. Screw implants were installed more than cylindrical implants. 3.8mm implant was the most common implans, followed by 4.5mm and 3.25mm. 5.The number of augmentation cases was more than that of non-augmentation cases and the rate of augmentation cases in the maxilla was more than that in the mandible. 6.Implant restorations for partial edentulos patients(94cases) were more than single- tooth implant restorations(33cases) or implant restorations for complete edentulos patients(10cases). 7.Free-standing prostheses for partially edentulous patients were more commom than any other type of connection between implants and natural teeth. 8.Plaque Index($0.95{\pm}0.74$) and Gingival Index($0.31{\pm}0.52$) were very similar around the natural teeth and reflected an acceptable level of plaque and gingivitis control. Mean value for keratinized mucosa index($1.93{\pm}1.20$) remained fairly constant around level 2(1-2 mm keratinized epithelium). 9.Patients were generally satisfied with implant in terms of comfort, function, speech and esthetics. 10.There was not a statistically significant differences in overall survial rate between implants placed in the maxilla (91.5%) and those placed in the mandible (93.8%). Fourteen implants lost before the prosthetic rehabilitation and eleven implants lost following variable periods in function after the prosthetic phase of the treatment. 11.Cause of implant failures was exfoliation or removal of fixture due to non-osseointegration before the prosthetic rehabilitation or due to fracture of fixture, masticatory pain after the prosthetic rehabilitation. 12.The survival rate of Steri-Oss implants using the Kaplan-Meier statistical analysis was 93.8% at 2 year and 86.6% at 5 year, In all cases, implant losses occured predominantly in the healing period. There was a steep decline in the rate of implant loss after the first year. 13.The survival rate of Steri-Oss implants in the anterior region was 94.8% at 2 year and 94.8% at 5 year and that in the posterior region was 92.8% at 2 year and 75.9% at 5 year. In conclusion, this study revealed a number of parameters and guidelines for achieving an optimal success rate in osseointegration.

• Journal of Life Science
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• v.23 no.10
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• pp.1288-1294
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• 2013

Knowledge of morphological changes in eel larvae is very important for artificial rearing of eel larvae. In this study, we investigated the morphological structure of the head region and histological changes of the eye retina in artificially reared larvae at various stages and in glass eel just after metamorphosis. Structural changes were observed in the upper jaw (maxilla) and the lower jaw (mandible) after 100 dah (day after hatchery) and after metamorphosis. Teeth had degenerated by the time of completion of metamorphosis. Major histological changes observed in the eye retina were the formation of the outer plexiform layer and the outer nuclear layer from 100 dah larva and a change in the rod cell layer after metamorphosis. The cornea was not observed at 10 dah in the eel larva. More information is needed on the early developmental stages of eel larvae to enable mass production of glass eels. The results obtained in the present research will be useful when developing novel rearing programs for eel larvae.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.267-273
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• 2014

This research has carried out to make a data base of taxonomic research. That Data base explains about spawning behavior, egg development, and morphologic development of variable sabretooth blenny. Fertilized egg was demersal egg which is white and opaque. The number of oil glouble were 10~11, and the size of egg was 0.90~1.43 mm (average rate $1.11{\pm}0.23mm$, n=10). Breeding water temperature was $25.5{\sim}28.5^{\circ}C$ (average rate $27.0^{\circ}C$), and salinity was 32.5~33.5‰ (average rate 33.0‰). After 24 hours from 2 cells, the process of egg development was reached to Blastula stage. Moreover, after 330 hours from 2 cells, nostrils and eyes were formed. Egg membrane was pierced by the head, and the hatch began. After the hatch, postlarvae had 2.59~3.02 mm (average rate $2.81{\pm}0.25mm$, n=5) of whole length, and the mouth and anus were opened. Yolk sac and oil glouble were absorbed. After three days from hatch, prelarvae were 3.02~3.07mm(average rate $3.04{\pm}0.04mm$) of whole length, and caudal fin was grown with round shape. After 13 days from hatch, prelarvae had 3.04~3.20 mm (average rate $3.12{\pm}0.11mm$) of whole length, and they could eat food with upper jaw and bottom jaw.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.123-129
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• 2017

This study investigated the dental prosthesis condition from the sixth primitive data of Korea National Health and Nutrition Examination Survey to analyze and compare the necessity of existent dental prosthesis condition, dental bridge and dentures in order to determine the real oral health condition by educational level targeting adults aged over 20 years old. From the results, based on demographic-sociologic features, 32.2% of females were under elementary school graduation level, which was lower than males, and the educational level decreased with increasing age, and these trends were statistically significant. As for income level, 45.3% of university graduates had the highest income level and 77.4% of this age group were professionals, which was the highest percentage and was statistically significant. In terms of dental prosthesis condition according to educational level, the under elementary school graduation group had the most dental prosthesis and the greatest need for partial dentures and full dentures. As for the necessary number of fixed implants, the upper jaw had the most number of fixed implants and in the lower jaw, the under middle school graduation needed the most fixed implants.