• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.789-801
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• 1995

Canals with artificially made internal resorption were filled with 4 techniques(Lateral condensation, Ultrafil, Obtura II, Thermafil) to compare the efficacy of canal filling according to the filling techniques. After canal filling, radiographic examination, dye penetration through the apical portion and percentage of G-P filled area on the internal resorption area were evaluated. To examine the degree of crystal-like structure and the interface between filled G-P and canal wall, SM and SEM images were taken too. The results were as follows : 1. There was no statistically significant difference in apical microleakage among the 4 root canal filling techniques. 2. As a result of radiographic examination, Ultrafil was the best and Obtura II was acceptable but Lateral condensation and Thermafil showed unfavorable canal filling pattern similarly. 3. Ultrafil filled most of artificially made internal resorption area and Obtura II, Lateral condensation, Thermafil in that order filled unfavorably. 4. Degree of crystal like structure was the highest in the group filled with Ultrafil and those of Obtura II and Thermafil were similar and that of gutta percha used in Lateral condensation showed the lowest value. 5. Penetration of gutta percha into the dentinal tubules couldn't be seen in all groups. In the contact surface between the filled G-P and the canal wall, Lateral condensation showed relatively close sealing, Obtura II and Thermafil had irregular contact surface and Ultrafil showed regular filling pattern. 6. Contact surface between the core of Thermafil and the gutta percha showed close relationship without gap formation.

• The Journal of the Korean dental association
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• v.56 no.10
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• pp.567-571
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• 2018

Obturation is a important procedure of root canal treatment. Canal filling should be both provide a hermetic seal for the root canal system and eliminate leakage channel from the oral cavity. Gutta-percha have been the standard material of choice for root canal obturation. Canal filling has been aimed at maximizing the amount of gutta-percha and minimizing the amount of sealer. However recently, single cone technique has been introduced that include calcium silicate-based sealer and single gutta-percha cone. It is important to select an obturation technique that offers consistency and is easy to use. From the standpoint of appropriate technology, the single cone technique is thought to be useful for general dentist.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.54-61
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• 2014

Objective: This study aimed to propose clinical guidelines for placing miniscrew implants using the results obtained from 3-dimensional analysis of maxillary anterior interdental alveolar bone by cone-beam computed tomography (CBCT). Methods: By using CBCT data from 52 adult patients (17 men and 35 women; mean age, 27.9 years), alveolar bone were measured in 3 regions: between the maxillary central incisors (U1-U1), between the maxillary central incisor and maxillary lateral incisor (U1-U2), and between the maxillary lateral incisor and the canine (U2-U3). Cortical bone thickness, labio-palatal thickness, and interdental root distance were measured at 4 mm, 6 mm, and 8 mm apical to the interdental cementoenamel junction (ICEJ). Results: The cortical bone thickness significantly increased from the U1-U1 region to the U2-U3 region (p < 0.05). The labio-palatal thickness was significantly less in the U1-U1 region (p < 0.05), and the interdental root distance was significantly less in the U1-U2 region (p < 0.05). Conclusions: The results of this study suggest that the interdental root regions U2-U3 and U1-U1 are the best sites for placing miniscrew implants into maxillary anterior alveolar bone.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.659-664
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• 2004

Dens invaginatus is a developmental variation resulting from invasination of the tooth crown of root before calcification. Teeth most affected are maxillary lateral incisors. The malformation shows a broad spectrum of morphologic variations and frequently results in early pulp necrosis. Root canal therapy may present severe problems because of the complex anatomy of the teeth. So, the early diagnosis of such malformation is crucial and a preventive approach has been recommended. This report describes three cases of dens invaginatus treatment.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.126-131
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• 2014

Among dental traumas, horizontal root fractures are relatively uncommon injuries. Proper initial management and periodical evaluation is essential for the successful treatment of a root-fractured tooth. If pulpal necrosis develops, endodontic treatment is indicated, exclusively for the coronal fragment. Fragment diastases exert a great influence on healing at the fracture line and on pulpal necrosis. An adequately treated root-fractured tooth has a good prognosis. This case report describes the treatment and 2-yr follow up of 3 maxillary central incisors, first with horizontal root fracture, second with horizontal root fracture and avulsion, and third with horizontal root fracture and lateral luxation. All three cases were treated with mineral trioxide aggregate (ProRoot, Dentsply). During 2 yr of follow-up evaluation, the root-fractured teeth of the present patients were well retained in the arch, showing periodontal healing, even after endodontic treatment.

• Korean Journal of Medicinal Crop Science
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• v.23 no.4
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• pp.292-297
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• 2015

This study was carried out to have the basic and applied informations relating to develop the cultivation methods and to increase the productivity and quality of ginseng. 1 to 6 year old ginsengs of Jakyung cultivar were cultivated and the content and synthetic amount of carbohydrates were investigated with different plant tissues, growth stages, and years old. The concentration of total carbohydrates at six year old ginseng including water soluble and water insoluble carbohydrates was about 18.9%, 42.9%, and 43,6% in leaves, tap roots, and lateral roots, respectively. Water soluble carbohydrate of tap and lateral roots was slightly decreased from August until September, and then increased on November, whereas its water insoluble carbohydrate was increased from August to September and then decreased on November. Comparing with the content of carbohydrates of 1 to 6 year old ginsengs, it was continuously increased from one year old ginseng until five year old ginseng, however it was not increased much in six year old ginseng. The highest content of carbohydrates was at five year-old in all tissues of ginseng. Water soluble and water insoluble carbohydrates were significantly shown different in leaves, stems, tap roots, and lateral root at different growth stages and with different years old. The content of water soluble carbohydrate in the leaves was remarkedly higher compared to that of water insoluble carbohydrate, while in the root the content of water insoluble carbohydrate was clearly higher compared to the water soluble carbohydrate. Comparing with the synthetic amount of carbohydrates, water soluble carbohydrates was higher in the shoot than that in the root, whereas water-insoluble carbohydrates higher in the root than that in the shoot. Carbohydrates which would be utilized in ginseng tissues for short and long-term periods as major energy were appeared differently in between shoot and root, with different growth stages, and years old.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.389-393
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• 2004

This study was carried out to investigate the difference of growth characteristics, yield and extract content between upland and paddy ginseng cultured with 4­year-old ginseng in 2003. Although upland ginseng showed larger variation in yield than that of paddy ginseng, the average of it was greater than that of paddy ginseng because it showed better growth of aerial part and higher survival rate than that of paddy ginseng. Moisture content of fresh root was $71.8\%\;(68.5\~73.1\%),\;and\;72.7\%\;(70.2 \~74.9\%)$ on average in upland and paddy ginseng, respectively. Paddy ginseng showed higher hardness in taproot, and higher rate of rusty colored root than that of upland ginseng. The ratio of taproot dry weight in upland ginseng was smaller than that of paddy ginseng, while that of lateral root was larger in upland ginseng. Ratio of marketable root (>60g) to total harvested roots was $13.7\%\;(0.82\~8.0\%)\;and\;7.7\%\;(1.6\~12.6\%)$ in upland and paddy ginseng, respectively. Extract content did not show distinct difference between upland and paddy ginseng, but it showed large variation from $16.1\;to\;25.1\%$ in taproot, and from $24.2\;to\;32.5\%$ in lateral root depanding on the ginseng field examined.

• Journal of Environmental Science International
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• v.24 no.6
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• pp.755-762
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• 2015

The present study was conducted to develop seed treatment for the production of healthy and clean peanut sprout. Dry heat treatment of peanut seeds reduced the incidence of the rot. The seed treatment condition at $52^{\circ}C$ for 10 h. was the most efficient without inhibiting seed viability significantly. Seeds were dark cultured at $27^{\circ}C$ for up to 9 days. The treatment of Indole-B and gibberellic acid influenced germination, T50, fresh, dry weight, hypocotyl length, hypocotyl length diameter, root length, number of lateral root and epicotyl of peanut sprout. There were no differences in the germinability of peanut seeds between gibberellic acid treatment methods but higher fresh weight was observed in the GA3 solution spray after 2 hour water soaking. The general growth and lateral root development of peanut sprouts were suppressed by Indole-B which is used for inhibiting root formation and promoting hypocotyls. The treatment of gibberellic acid promoted hypocotyl elongation, but it did not influence on the growth of hypocotyls and root system.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.339-352
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• 1996

Many dentists have been taken an interest in restoration of severly damaged teeth after endodontic treatment and it is a true that there are lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the effects of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper 1st premolar was severly damaged, and after the root canal therapy, two most common types of restoration were carried out ; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with amalgam core and gold crown. After restoration, in order to present the concentration of stress at internal portion of the tooth and the surrounding periodontal tissue, we doveloped a 2-dimensional finite element model of labiopalatal section, then loaded forces from 2 long perpendicular to the lingual incline of buccal ridge an the middle point, parallel to the long direction axis of tooth at the fossa-were applied. The analyzed results were as follows : 1. Stress of the normal first premolar was concentrated on the most weakest anatomical structure, that is, cervical area, and no stress on the bifurcated area of the canal. 2. Crown restoration after root canal therapy causes large stress concentration on the bifurcated area of the canal. This stress concentration has larger value in case of lateral movement of mandible, and there are decrease in the stress concentration compared with natural tooth. 3. Coronal-radicular amalgam restoration method transports more stress to the tooth structure than restoration using Para-Post. 4. There are more stress concentration around Para-Post in the case of lateral movement, and we have more favo rable result when restored with Para-Post. 5. Generally, stress in the lateral movement is larger than stress in the perpendicular load.