• Imaging Science in Dentistry
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• v.42 no.3
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• pp.147-154
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• 2012

Purpose: This study was performed to evaluate the incidence and degree of external apical root resorption of maxillary incisors after orthodontic treatment and to evaluate particular associated factors related to external apical root resorption. Materials and Methods: The records and maxillary incisor periapical radiographs of 181 patients were investigated. Crown and root lengths were measured and compared on the pre- and post-treatment periapical radiographs. Crown length was measured from the center of the incisal edge to the midpoint of the cemento-enamel junction (CEJ). Root length was measured from the CEJ midpoint to the root apex. A correction factor for the enlargement difference was used to calculate root resorption. Results: The periapical radiographs of 564 teeth showed that the average root resorption was $1.39{\pm}1.27$ ($8.24{\pm}7.22$%) and $1.69{\pm}1.14$ mm ($10.16{\pm}6.78%$) for the maxillary central and lateral incisors, respectively. The results showed that the dilacerated or pointed roots, maxillary premolar extraction cases, and treatment duration were highly significant factors for root resorption (p<0.001). Allergic condition was a significant factor at p<0.01. Age at the start of treatment, large overjet, and history of facial trauma were also factors significantly associated with root resorption (p<0.05). There was no statistically significant difference in root resorption among the factors of gender, overbite, tongue-thrusting habit, types of malocclusion, and types of bracket. Conclusion: These results suggested that orthodontic treatment should be carefully performed in pre-treatment extraction patients who have pointed or dilacerated roots and need long treatment duration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.292-296
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• 2003

The lateral root formation in soybean sprout culture declines its quality. This study was done to measure the effect of fluorescent light treatment during 24 hour imbibition and 6-day culture on seed germination and growth of soybean sprout. After 6 day culture, the sprouts were sorted as normal (＞4cm), abnormal (＜4cm) and non-germination by their hypocotyl lengths, and lateral roots, fresh and dry weights were measured. Lateral roots were less formed in the fluorescent light treatment lasted during the whole period of the imbibition than in the treatment for 50 minutes a day during the culture. The fluorescent light treatment during the imbibition mainly affected the germination and growth compared to the treatment done during the culture. Compared to the dark imbibition, the light treatment during the imbibition resulted in more normal sprouts, thicker diameters of hypocotyl and hook, and more fresh weights in cotyledon, hypocotyl, whole sprout, and economic yield. However, these results were reverse in lengths of hypocotyl and root, and fresh and dry weights of roots. It is concluded that the fluorescent lamp mainly irradiating red and blue lights can be used for the sprout production as an alternative light replacing blue and red lights treated during the imbibition because it blocked the lateral root appearance and stimulated growth of the sprout.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.150-160
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• 1996

The present study was to evaluate the accuracy of the frequency dependent type apex locator, Root-ZX. The subjects included 505 root canals of 238 teeth treated by the Department of Conservative Dentistry, and 22 human premolars which were schduled to be extracted for the orthodontic reasons. The results were as follows ; 1. The working lengths determined by Root-ZX were compared with radiographic readings. Of the total 505 root canals, 66 % showed coincidence within ${\pm}0.5mm$ and the average readings of Root-ZX were $0.13mm{\pm}1.05$ longer than those of radiographic readings. 2. The length difference between the file tip determined by Root-ZX and the apical constriction in extracted teeth were measured. Of the total 24 root canals, 70.8 % showed coincidence within ${\pm}0.5mm$ and the average readings of Root-ZX were $0.12mm{\pm}0.50$beyond the apical constriction. 3. The vitality of the teeth did not show any statistical difference(p>0.05) in the accuracy of the Root-ZX readings. The presence of the periapical lesions, however, significantly lowered the percentage of ${\pm}0.5mm$ accuracy in Root-ZX measurements.(p<0.05). In the presence of periapical lesions, the percentage within ${\pm}0.5mm$ was significantly lower.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.381-390
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• 2018

This study was conducted to examine the growth characteristics of seedlings of several major fruit vegetables and compare them between plants grown with the conventional plug seedling system (Plug) and those grown with the cylindrical paper pot system (CPP). There were no significant differences in shoot growth characteristics, such as plant height, leaf area, dry weight, and fresh weight, between tomato, cucumber, and watermelon plants grown with the CPP and Plug systems. The total root lengths of tomato and cucumber plants grown with Plug were longer than those grown with CPP at the beginning of seedling growth, and the total root lengths of watermelon grown with Plug were longer than those grown with CPP throughout the whole seedling period. The length of root that separated five steps according to the diameter of the root of tomato did not differ between CPP and Plug, but those of cucumber and watermelon were 20-251% longer with Plug than with CPP for all kinds of roots. The fresh weight of Plug-grown tomato roots was about 30% heavier than that of CPP-grown tomato during the seedling period, but the difference decreased as growth progressed. Finally, there was no difference between plants before and after transplanting. The fresh weights of the Plug-grown plants were about 20-30% heavier than those of CPP-grown ones in terms of the whole seedling. After transplanting to the Wagner pot, the shoot growth of Plug-grown watermelon plants in terms of dry weight was low until 7 days had passed. However, this tendency was reversed from 8 days after transplantation onward. In conclusion, there were no significance differences in the growth of shoots between plants grown with the CPP and Plug systems. However, root development was better with Plug than with CPP.

• Restorative Dentistry and Endodontics
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• v.30 no.6
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• pp.477-485
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• 2005

The aim of this study was to compare the length between the mesio-buccal and mesio-lingual canal of the mandibular molars before and after early coronal flaring at the different measuring time using several electronic apex locators. Fifty mandibular molars with complete apical formation and patent foramens were selected. After establishing the initial working length of the buccal and lingual canal of the mesial root using a surgical microscope (Carl Zeiss Co Germany) at 25X with #15 K-fle tip just visible at the foramen, radiographs were taken for the working length. After measuring the length of mesio-buccal and mesio-lingual canal (control group), the electronic lengths were measured at different times using several electronic apex locators (experimental groups; I-Root ZX, II-Bingo, III-Propex, IV-Diagnostic). After early coronal flaring using the $K^3$ file, the additional electronic lengths were measured using the same manner The results were as follows: One canal has a correct working length for the mesial root of the mandibular molar, it can be used effectively for measuring the electronic working length of another canal when the files are superimposed or encountered at the apex. In addition, the accuracy of the electronic apex locators was increased as the measurement was accomplished after the early coronal flaring of the root canal and the measuring time was repeated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.146-152
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• 1997

Development of shoot and root, leaf water potential and photosynthetic rate affected by water stress in early growing stage of tobacco were surveyed to interpret stress response in terms of plant physiological and agricultural aspects. The growth of shoot and root was highly suppressed by water stress and the difference in dry weight by rewatering was smaller in root than in shoot. The total root length was highly decreased by water stress and the lengths of root for water stress and non-stress were 74m and 84m, respectively, after rewatering. The root growth treated by water stress was increased between 2nd and 3rd day after treatment indicating that temporary water stress at early growing stage might have increased of root zone activity for early growth stage. The leaf water potentials were decreased to -7.63MPa, -9.47MPa, -11.89MPa, -13MPa at the 2nd, 3rd, 4th and 5th day by water stress. The relative water contents were 75%, 62% and 57% at the 3rd, 4th and 5th day after treatment. Photosynthesis was reduced largely by water stress. The photosynthetic rate after treatment at 2nd day and 3rd day was dropped to 18.15$\mu$mol. $CO_2$/$m^2$ㆍsec$^{-1}$ and 9.35$\mu$mol. $CO_2$/$m^2$ㆍsec$^{-1}$. It was never recovered to the normal, even after rewatering. Stomatal conductance had been reduced since 2nd day after treatment and increased after rewatering.

• Restorative Dentistry and Endodontics
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• v.37 no.3
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• pp.175-179
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• 2012

The aim of this study was to present a method for endodontic management of a maxillary first molar with unusual C-shaped morphology of the buccal root verified by cone-beam computed tomography (CBCT) images. This rare anatomical variation was confirmed using CBCT, and nonsurgical endodontic treatment was performed by meticulous evaluation of the pulpal floor. Posttreatment image revealed 3 independent canals in the buccal root obturated efficiently to the accepted lengths in all 3 canals. Our study describes a unique C-shaped variation of the root canal system in a maxillary first molar, involving the 3 buccal canals. In addition, our study highlights the usefulness of CBCT imaging for accurate diagnosis and management of this unusual canal morphology.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.231-231
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• 2017

Drought limits rice production under upland condition. This study quantified the effect of rhizobacteria inoculation on rice root system developmental response to drought and its role in maintaining high soil water use, and dry matter production under drought using NSIC Rc192 (rainfed lowland rice variety). The source of inoculant was Streptomyces mutabilis, a recently isolated rhizobacteria containing plant growth promoting compounds such as ACC deaminase, indole-3-acetic acid and phosphatase (Cruz et al., 2014, 2015). In the first experiment, pre-germination inoculation of seeds with S. mutabilis significantly increased the shoot and root (radicle) length as well as root hair lengths, relative to the non-inoculated control. In the second experiment, rice plants inoculated with S. mutabilis and grown in rootbox with soil generally had greater total root length under drought regardless of the timing of inoculations, relative to the non-inoculated control. Consequently, improved root system development contributed to the increase in soil water uptake under drought and thus, dry matter production. Among inoculation treatments, one-time inoculation of S. mutabilis either at pre-germination or pre-drought stress at 14 days after sowing (DAS), had significantly greater shoot dry matter production than three-time inoculation at pre-germination, at thinning (3 DAS) and at pre-drought (14 DAS). This study demonstrated the effectiveness of rhizobacteria (S. mutabilis) containing growth promoting compounds for enhancing drought dehydration avoidance root traits and improving the growth of rice plants under drought condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.204-208
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• 2006

Utilization of synthetic benzyladenine (BA) for bean sprout production should be reduced or minimized because of elevating production cost and not ascertaining action mechanism to human body. The study was done to compare the effects of BA concentrations under different watering methods (overspraying or underwatering) on growth and morphological characteristics of mungbean sprouts. Seeds of cv. Zhong-Lu 1 were soaked for 5 hours in the solutions with different BA concentrations (0, 10, 20, 30, 40, 50 ppm) before 4 hour aeration, and then were cultured for 6 days by both watering systems. Their morphological characters, fresh and dry weights were measured. Regardless of watering methods, lateral roots were sharply dropped over 30 ppm BA concentrations, and hypocotyl, root and total lengths were shortened with increased BA concentrations although ratios of hypocotyl to root lengths and hypocotyl diameters were enlarged with their increment. Total fresh weights were increased up to 20 ppm in overspraying method but up to 30 ppm in underwatering method mainly due to increment of hypocotyl fresh weights. The sprouts were faster grown in overspraying method than in underwatering method because the former showed longer lengths of hypocotyl and root, and total fresh weights.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.296-302
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• 1989

The mesocotyl elongation, having much effect on emergence and stand establishment in the direct sowing culture of rice, was investingated and summarized as follows: As to origin of cultivars, the average lengths of mesocotyl were 9.6 mm in the Indica-Japonica hybrid cultivars, 4.4 mm in the native cultivars and 3.2mm in the Japonica type, respectively. The mesocotyl lengths were tjereh, aman, aus, boro and bulu in order, with the mesocotyl lengths of 29.3mm and 5.4 mm in tjereh and bulu, respectively. The mesocotyl lengths were great in Baekkyungjo, Dadajo & Hejo among the native cultivars, in Sangpungbyeo, Paltal & Gokyangdo of the Japonica type and in Weonpungbyeo, Gayabyeo, Milyang 30 & Sujeongbyeo in Indica- Japonica hybrid cultivars, respectively. The mesocotyl length was the greatest at the seeds sampled I week after flowering (39. 3mm in length), and became decreased with the longer grain-filling. The mesocotyl elongated worse with the longer duration of seed storage regardless of seed maturity, and became longer at the 5$^{\circ}C$ storage plot than at the 15 and 25$^{\circ}C$ plots.