• Economic and Environmental Geology
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• v.17 no.3
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• pp.215-230
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• 1984

Petrological, paleomagnetic, geomorphological and structural studies on the southern part of, so called, Chugaryeong rift valley, have been carried out in order to clarify the nature of the rift valley. Three stages of volcanic activities characterized by Jijangbong acidic volcanic rocks and tholeiitic and andesitic basalt of Cretaceous age(?), and Jongok Quaternary olivine basalt occurred along the Dongducheon fault line. Jijangbong acidic volcanic rocks distributed in the central part of the studied area consist of rhyodacite, acidic tuff and tuff breccia, which are bounded by Dongsong fault on the east and Daegwangri fault on the west. The Jongok basalt differs from those of Ulrung and Jeju islands in mineralogy, chemical composition and differentiation. Jongok basalt distributed along the Hantan river dilineates the vesicles curved toward downstream direction and increment of numbers and thickness of lava flow toward upstream direction. These facts suggest that lava flowed from upstream side of the river. Rectangular drainage patterns also support the presence of the Dongducheon, Pocheon, Wangsukcheon and Kyonggang faults which were previously known. LANDSAT image, however, does not show any lineaments which could be counted as a graben or rift valley. Displacement of Precambrian quartzite and Jurassic Daedong supergroup along the southwestern extension of the Dongducheon fault shows the right lateral movement. The Paleomagnetic study of the tholeiitic and andesitic basalts from Baegeuri, Jangtanri and Tonghyeonri located at 2. 3km east, 0km east, and 1.5km west of Dongducheon fault respectively shows that their VGP(Virtual Geomagnetic Pole) being to intermediate geomagnetic field of short duration which suggests that they formed in almost same period. Mean VGP of Jongok basalt is located 82.4N and 80.6E. This is in good coincidence with worldwide VGP of Plio-Pleistocene indicating that Jongok basalt was extruded during Plio-Pleistocene epoch, and suggesting that the studied area has been tectonically stable since then. From the present study, the tectonic episode of the region is concluded as following three stages. 1. The 1st period is worked by the Daebo orogeny of Jurassic during which granodiorite was intruded in Precambrian basement. 2. The 2nd period is the time when right lateral strike-slip fault of NNE-SSW direction was formed probably during late Cretaceous to Paleogene and the Jijangbong acidic volcanic rocks and the older basalts were extruded. 3. The 3rd period is the time when the fault was rejuvenated during Pliocene or Pleistocene accompanied by the eruption of Jongok basalt. As a conclusion, geologic structure of the studied area is rather fault line valley than graben or rift valley, which is formed by differential erosion along the Dongducheon fault suggesting a continuation of the Sikhote-Alin fault. The volcanic rocks including the Jijangbong acidic rocks, tholeiitic-andesitic basalt and olivine basalt are associated with this fault line.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.292-299
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• 2000

The purpose of this study was to investigate parental knowledge and attitude and practices relating to infant oral health care and to promote their motivations to their children's oral health care. Authors interviewed 350 persons in Ilwon-Dong and whose children were between 0 to 36 months old and acquired questionnaire from them. The questionnaire constituted of questions about general knowledge of tooth eruption, methods of oral hygiene care, and opinions about preventive dental visit. The collected data were analysed and compared with other researches. The important results obtained from this study were : 1. Females and highly educated persons had more dental knowledge than males and poorly educated persons. But age and economic status did not affect their level of dental knowledge. 2. Fifty nine percents of respondents thought that tooth began to be formed before birth. 3. Seventy six percents of respondents thought that infant oral health care should begin before tooth eruption, but actually only 63% started oral hygiene care before age one. 4. Seventy percents of respondents used gauze for infant oral care. 5. Fifty seven percents of respondents still gave bottles to their children after they reached age one or more and 55% of respondents never heard of nursing caries. 6. Ninety percents of respondents agreed that carious deciduous teeth need restorations, and 31% of respondents thought that age two is the appropriate time for the first dental visit. 7. Forty seven percents of parents did not think that dental caries is an infectious disease. 8. Only Thirty three percents of parents visited dental clinics for examination and prevention during pregnancy and only 11% of expecting parents were offered dental health care education in pediatric or obstetrician clincs. 9. Information about oral health care was mostly given from baby megazines. 10. Overall parental knowledge about infant oral health care was not sufficient to maintain appropriate dental care for infants.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.140-149
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• 2007

Cleft lip and palate are congenital craniofacial malformation. Reconstruction of dental arch in patient with alveolo-palatal clefts is very important, because they have many problems in functions and esthetics. Malnutrition, poor oral hygiene, respiratory infections, speech malfunctions, maxillofacial deformity, and psychological problems may be occured without proper treatment during the long period of management of the cleft lip and palate. So the treatment should be managed with a multidisciplinary approach. Bone grafting is a consequential step in the dental rehabilitation of the cleft lip and palate patient A complete alveolar arch should be achieyed of the teeth to erupt in and to form a stable dentition. And the presence of the cleft complicate the orthodontic treatment. Therefore bone grafting in patients with cleft lip and palate is a widely adopted surgical procedure. Grafted bone stabilizes the alveolar process and allows the canine or incisor to move into the graft site. After the bone grafting, orthodontic closure of the maxillary arch has become a common practice for achieving dental reconstruction without any prosthodontic treatment. Various grafting materials have been used in alveolar clefts. Iliac bone is most widely fovoured, but tibia, rib, cranial bone, mandible have also been used. And according to its time of occurrence, the bone graft may be divided into primary, early secondary, secondary, late secondary. Bone grafting is called secondary when performed later, at the end of the mixed dentition. It is the most accepted procedure and has become part of treatment of protocol A secondary bone graft is performed preferably before the eruption of the permanent canine in order to provide adequate periodontal support for the eruption and preservation of the teeth adjacent to the cleft. In this report, we report here on a patient with unilateral cleft lip and palate, who underwent iliac bone graft. The cleft was fully obliterated by grafted bone in the region of the alveolar process. The presence of bone permitted physiologic tooth movement and the orthodontic movement of adjacent tooth into the former cleft area. Satisfactory arch alignment could be achieved in by subsequent orthodontic treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.439-443
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• 2002

The purpose of this study was to analyze the parental consultation. Also, it was to investigate the tendency divided into different subjects. The subjects were 2142 questions on korean academy of pediatric dentistry homepage. The questions were categorized into 7 subjects, 37 subdivided subjects and children age. The results were as follows: 1. Age group was divided into $0{\sim}6months$, $7{\sim}12months$, $13{\sim}24months$, $25{\sim}36months$, $3{\sim}6years$, $7{\sim}12years$ 12years and over 13 years. $13{\sim}24months$ and $3{\sim}6years$ age group had the largest number of questions. 2. The subject were growth & development, development disturbance & oral disease, behavior management, operative & endodontic treatment, dentition & occlusal guidance, traumatic injury & surgery and etc. Development disturbance & oral disease had the largest number of questions. 3. In subdivided subjects, operative & endodontic treatment showed the most, followed by development & eruption of teeth, traumatic injury, cross-bite, tooth brushing methods in sequence. 4. In age group within subdivided subjects, the most frequent question was neonatal & natal tooth in $0{\sim}6months$, development & eruption of teeth in $7{\sim}12months$, $13{\sim}24months$, operative & endodontic treatment in $25{\sim}36months$, $3{\sim}6years$, time & method of orthodontics in $7{\sim}12years$ and operative & endodontic treatment in over 13years. 5. The questions about cross-bite, traumatic injury and soft tissue disease were distributed evenly in age group.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.84-88
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• 2009

Tooth impaction refers to situations where a tooth fails to erupt due to mechanical blocking and remains unerupted beyond the normal time of eruption. It is commonly found in permanent dentition, but rarely in deciduous dentition. Tooth impaction is caused by systemic or local factors, and most common etiology is odontoma. Odontoma is also commonly found in permanent dentition, and rarely in deciduous dentition. We are presenting case of 4 year and 4 month year old girl, who had impacted and disto-angulated lower left deciduous second molar due to odontoma. We removed odontoma and performed orthodontic traction of impacted lower left deciduous second molar. Then, the impacted primary molar was erupted and acceptable occlusion was obtained.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.91-95
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• 2009

The use of stainless steel crowns are indicated for restoration of primary or permanent molars with proximal dental caries, extensive dental caries, or previous pulp treatment with increased danger of tooth fracture. Stainless steel crowns were introduced by Humphrey in 1950. For their improved durability, longevity, and success rate, they have been strongly considered for restoring extensive and multi-surfaced dental caries of molars in pediatric dentistry. However, they also have shortcomings, such as possibility of pulpal exposure or damaging proximal surface of adjacent teeth. In addition, when oversized stainless steel crowns are used, eruption of the adjacent permanent teeth may be disturbed by their prominent margin. As a means to compensate the shortcomings of stainless steel crowns, use of orthodontics bands may be considered. It is an alternative restoration method, where an orthodontic band is placed on a tooth first and cavity is restored with filling material, such as composite resin, glass ionomer, or amalgam. The use of an orthodontic band is indicated for molar restoration with cervical dental caries, extensive dental caries, enamel hypoplasia, or previous pulp treatment. Because it requires shorter chair time compared to stainless steel crown, its application is very useful for children with poor behavior. However, restoration using an orthodontic band requires good oral hygiene after its application. This case report illustrates the conservative restoration of primary molars and permanent molars with extensive dental caries using orthodontic bands.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.246-251
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• 2010

Impactions can occur because of malpositioning of the tooth bud or obstruction in the path of eruption. However, the exact mechanism is still unknown. The impaction of mandibular first molar is rare with prevalence rates of 0.01~0.25%, but it is important to deimpact the tooth as soon as possible to avoid complications such as dental caries, root resorption, and periodontal problems on the adjacent teeth. Several biomechanical strategies have been proposed for uprighting mesially tipped mandibular first molars. However, most of these have had problems with movement of the anchorage unit because of the reciprocal force. The recent development of skeletal anchorage system(SAS) allows direct application of precise force systems to the target tooth or segment, producing efficient tooth movement in a short time. In this case, an impacted mandibular left first molar with dilacerated roots was treated with a miniplate, which provided skeletal anchorage to upright the tooth. The miniplate was installed in the mandibular ramus, and 10 months after the application of orthodontic force, the impacted tooth was exposed in the oral cavity and uprighted. At this point, the mandibular left first molar was included in the orthodontic appliance with fixed mechanotherapy, the tooth could achieve a normal occlusion. Therefore, the use of SAS simplified the orthodontic procedures and reduced the orthodontic treatment period, and had few side effects.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.157-166
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• 2020

The first dental visit is recommended at the time of the eruption of the first tooth and no later than 12 months of age. However, even before the age of 1, children can visit the dental hospital for various reasons. The purpose of this study was to analyze the reasons for the dental visit of infant. From January 2006 to December 2015, medical records of infants who visited the Department of Pediatric Dentistry of Kyung Hee University were analyzed. The total number of patients was 419 (238 males and 181 females). The reasons for the dental visits were trauma (47.5%), natal/neonatal tooth (19.8%), dental caries (8.1%), teething problem (4.3%), abnormal frenum (3.6%), soft tissue swelling (3.6%), Bohn's nodule (3.3%), cleft lip and palate (2.9%), gingival neoplasm (1.9%), tongue ulceration (1.7%), oral examination (1.4%), enamel hypoplasia (1.2%) and abnormal temporomandibular joint sound (0.7%). According to this study, there were various oral diseases that could occur in infants. Since infants are usually cared by caregivers, pediatricians, and obstetricians, education of oral diseases of infants is needed to manage the oral symptoms properly.

• The korean journal of orthodontics
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• v.29 no.1 s.72
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• pp.23-35
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• 1999

Lateral cephalograms or 251 males md 286 females were taken and pubertal growth pattern or cranial base, maxillary and mandible of 7 to 17 years old Korean children was evaluated. 10 landmarks and 16 analytical measurements were evaluated. Analytical measurement and annual difference for each age group was calculated and tested for statistical significance. Analytical measurements were classified into three groups which were cranial base, maxillary and mandibular measurements and also classified into make and female measurements. Following results were achieved. 1. The circumpuberal growth spurt was earlier in Korean females than in males. 2. Cranial base, maxilla and mandible showed circumpuberal growth. The cranial base showed a relatively smaller amount of growth than the facial complex. 3. Middle and posterior cranial base length showed a floater increase than anterior cranial base length and circumpuberal growth spurt was also more definite. 4. the forward and downward growth or maxilla results from maxillary growht itself and transposition or the maxilla due to circumsutural growth aroud the maxilla. Ar-ANS and Ar-Pr which represent maxillary position relative to the cranial base showed more growth than ANS-PNS which represents maxillary bone growth. 5. mandible showed more vertical growth than horizontal growth but without significance. 6. Alveolar gwoth of maxilla and mandible show maximum growth rate of the time of permanent teeth eruption following loss of deciduous teeth . After this period alveolar growth shows a decreasing tendency.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.737-743
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• 2008

Regional odontodysplasia is a relatively rare developmental anomaly of dental hard tissue with characteristic clinical, radiographic and histologic features. It requires a continuous and multidisciplinary approaches, and the aim of treatment for these patients should include aiding mastication, improving aesthetics, maintaining normal vertical dimension and space, allowing normal jaw growth and eruptional management of affected teeth. This report describes three cases of regional odontodysplasia with 2-5 years of follow-up. Conservative treatment is chosen to preserve the affected teeth as long as possible, and periodic radiographic and clinical examination was done. During this time, all teeth except one showed progressive development. An interesting finding observed in our cases was that each tooth even in the same person showed different degree of tooth development and eruption rate. Thus, we colcluded that the treatment plan for regional odontodysplasia should be conservative and individualized and based on the assessment of each tooth.