• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.25-35
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• 2020

The purpose of this study is to evaluate the morphological characteristics of the roots and roots canals of primary molar teeth using Cone-Beam Computed Tomography (CBCT). A total of 68 CBCT images of children aged 4 - 5 years was used for this study. A total of 160 molar teeth were analyzed. Various parameters such as the number of roots and canals, length of root and root canal, and the angulation and shape of the roots were analyzed. All maxillary primary molars had 3 roots. The presence of 2 root canals in 1 root was only observed in the mesiobuccal root of maxillary primary second molars. Most mandibular primary molars had 2 roots, and most mesial roots had 2 root canals. Concerning the length of the roots, the palatal root of the maxillary primary molar was found to be longest whereas the distobuccal root was shortest. In mandibular primary molars, the mesial root was longer than the distal root. In maxillary primary molars, the palatal root had the greatest angulation whereas the distal root has the greatest in mandibular molars. The root and root canals of maxillary primary molars were more curved in shape whereas mandibular primary molars were straight.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.4
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• pp.400-408
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• 2019

The purpose of this study is to identify the most common canal type in primary molars and the correlation between their roots and canals. A comprehensive understanding of root canal morphology will lead to more successful root canal treatment. Computed Tomography (CT) images from 114 children (81 boys, 33 girls) aged 3 - 7 years were obtained. The locations and numbers of roots and canals were evaluated, and the relationship between root and canal parameters was determined. The most commonly observed canal morphology in primary maxillary molars were mesio-buccal, disto-buccal and palatal canal. Primary mandibular molars most frequently contain mesio-buccal, mesio-lingual, disto-buccal and distolingual canal. All the roots of the primary maxillary molars except for the mesio-buccal root, each had 1 canal while there were 2 canals observed in each root of primary mandibular molars. Without exception, all mesial roots in primary mandibular 2nd molars had 2 canals. In case when either the palatal root in a primary maxillary molar or the distal root in a primary mandibular molar was separated into 2 roots, each root seemed to have its own canal. Even though the disto-buccal and palatal roots were fused into 1 root in primary maxillary molars, this fused root had tendency to have 2 separate canals. Primary mandibular molars showed similar canal morphologies between left and right molars in the same patient, while the primary maxillary molars did not.

• The Journal of the Korean dental association
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• v.57 no.8
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• pp.474-479
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• 2019

The purpose of the pulp treatment is to make the function of the primary molar in the oral cavity possible for as long as possible until the exfoliation of the tooth or the development of the occlusion is as long as possible. The pulpectomy is a relatively common procedure for the pediatric dentist in the clinic with dental care of the children nowadays. Primary molar is morphologically more susceptible to dental caries than permanent tooth, and the dental pulp treatment is frequently performed. Furthermore, unlike permanent teeth, the root canal has a large degree of curvature and morphological diversity and complexity, careful consideration is needed. Therefore, it is very important to comprehensively understand the morphological characteristics and diversity of the root and root canals for the successful pulp treatment of the primary molars.

• The Korea Journal of Herbology
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• v.33 no.1
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• pp.85-91
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• 2018

Objectives : This study was carried out to evaluate the quality of different drying methods and different roots(primary root and lateral root) of Angelica gigas Nakai. Methods : The experimental method was performed according to the Korea Pharmacopoea Eleventh edition (KP11). Loss on drying, ash, acid insoluble ash, ethanol extract, nodakenin and total decursin contents were tested to evaluate the quality of root tissue of Angelica gigas Nakai. In addition, the treatment of different root parts were prepared in two groups of washing dry process and natural dry process. Results : In comparison of dry processing methods, total contents of nodakenin and total decursin in the primary root and lateral root through washing dry process were ranged from 3.55 to 4.09% and from 5.18 to 6.13%, respectively. And also, those of roots from the natural dry process were from 4.36 to 6.22% and from 6.28 to 8.34%, respectively. In the washing dry process and natural dry process methods, 47.9% and 22.3% higher amount of nodakenin and total decursin were measured in lateral root compared to primary root. In common, lateral roots accumulated higher contents of nodakenin and total decursin compared to primary roots, and samples drying processed with natural dry process compared to washing dry process method contained higher amount of compounds. Conclusions : We sincerely hope that this study will be contributed to the standardization and quality control of Angelica Gigas Root.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.571-577
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• 2008

Root fracture of primary teeth is relatively uncommon because the more pliable alveolar bone allows displacement of the tooth. Root fracture of primary teeth is occupied $2{\sim}7%$ in trauma pattern of primary teeth. A horizontal root fracture is classified based on the location of the fracture in relation to the root tip : the apical third, middle third, or cervical third of the root. The prognosis worsens the further cervically the fracture has occurrer. Root fracture of primary teeth should be treated by splinting the incisor to the adjacent normal teeth with a resin-wire splint for $8{\sim}12$ weeks. However, if a portion of the root is abscessed or extremely mobile, it can be extracted, and the remaining root fragment will resorb normally. For coronal third fracture in primary teeth, the coronal third is extracted, leaving the apical portion of the root to resorb normally. These root fracture cases of primary teeth were treated by resin-wire splinting despite extremely mobile coronal fragment. Even though they seems like healing well, They need to be monitored regularly until their successors erupt.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.605-610
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• 2003

Physiologic root resorption occur from the apex of the primary teeth close to the permanent teeth towards the apex. Pathologic root resorption occur on surfaces of root due to causes such as trauma, replantation, orthodontic treatment, delayed or irregular eruption of teeth, or growing cysts or tumors. In children, the most frequently affected teeth from trauma are the maxillary primary central incisors. After such an event, root resorption initiate from the traumatized pulp or periodontium. In this case report, periapical radiographs were used to evaluate the features of pathologic root resorption by studying patients with history of trauma. The following results were noted. 1. Pathologic root resorption was observed in various patterns in all of the 10 traumatized maxillary primary central incisors. 2. Though teeth with pathologic root resorption were treated with pulpectomy, the resorption process continued to progress.

• Journal of Plant Biology
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• v.26 no.4
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• pp.207-216
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• 1983

Mature embryo and developing seedlings of Ginkgo biloba L. were embedded in a paraplast and serially sectioned at 10${\mu}{\textrm}{m}$ to examine vascular differentiation and vascular transition. Procambium and protophloem formed a continuous system along the epicotylhypocotyl root axis and cotyledons in mature embryo, whereas protoxylem was differentiated discontinuously in the cotyledons and rarely in the upper hypocotyl. The traces of the first and second leaf primordia apeared almost at the same time oppositely to each otehr at the epicotyl and alternately with the cotyledon traces in the upper hypocotyl. The trace differentiated bidirectionally toward the epicotyl and root tips. the young root initially formed a diarch xylem. Then, as the traces of the first and second leaves were superimposed, the diarch xylem. Then, as the traces of the first and second leaves were superimposed, the diarch xylem of the root was changed totriarch and tetrarch xylem, respectively. On the formation of primary vascular system of Ginkgo biloba, it is suggested that the primary phloem forms a continuous system throughout the seedling, whereas the primary xylem of the epicotyl is formed independently from that of the root-hypocotyl cotyledon system.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.116-121
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• 2017

An additional root of the primary maxillary second molar is rarely observed. Two cases are presented herein, and we discuss a possible association between additional root of the primary maxillary second molar and displacement and rotation of the permanent successor. Investigation of crown morphology enables the detection of a potential additional root of the primary maxillary second molar, and eruption of the permanent successor needs to be examined carefully if an additional root is present. Early extraction of primary molar and space maintenance can be used as a conservative treatment if the premolar germ shows an abnormal eruption pattern.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.156-161
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• 2007

Pediatric dentists are frequently encountered with fractured root fragments of primary teeth caused either by the traumatic injuries or by the accidental fractures during the procedure of tooth extractions. In these situations, we often hesitate which method to choose, extract or retain it. In general, it is recommended to retain apical fragments, as the attempts to extract the apical fragments might harm the developing permanent tooth germ. This study was designed to ensure the validity of intentional retention of the root fragments of primary teeth in the situations described above. 6 children with intentionally root fragments who experienced root fracture in primary anterior teeth were available Periodic radiographic assessment was performed at 3 months interval for $7{\sim}37$ months. The results of this study showed that apical fragments had been resorbed through physiologic process in 5 patients. Apical fragment had been gingival emergence along with the erupting permanent tooth in 1 patient. There were no evidence of interference with eruption of permanent successors. In summary we have been ensured the validity of intentionally retention of the root fragments of primary teeth. Children with being remained apical root fragment should be recalled regularly for assessment and parents should be thoroughly informed about the situation with special emphasis on the necessity of periodic check-up.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.305-308
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• 2002

Decursinol angelate, a new anticancer agent, was produced by root cultures of Angelica gigas Nakai. In addition, difference of specific yields between primary and secondary root was investigated. It was found that specific yield of secondary root was much higher than that of primary root at various conditions, so that it was thought that the formation and growth of secondary root were feasible. From this point of view, effects of root segmentation and plant growth regulators (NAA, IBA) on root morphology and decursinol angelate production were examined. Root segmentation increased secondary root mass and product formation. On the other hand, addition of NAA or IBA at various concentrations promoted secondary root formation and production of decursinol angelate significantly. Five-fold increase of production was obtained at 4 mg/L of IBA compared to control without NAA and IBA.