• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.119-128
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• 1992

In order to evaluate the relationship of age with the developmental stage on mandibular second molars in female, the author examined the radiographs in standard films taken by intraoral paralleling technic and analysed the development of 620 roots of 310 females ranged from 10 to 18 years. The development was divided into 7 stages : Crown complete (Cr.C.), Root lengthed 1/4(R.1/4), Root length 1/2 (R.1/2), Rooth length 3/4 (R.3/4), Rooth length complete (R.C), Apex 1.2 closed (A. 1/2), Apical closure complete (A.C) The obtained results were as follows : 1. The formation of roots in fulllength of mandibular second molars was completed at 14.21-year-age in mesial root and at 14.96-year-age in distal root. 2. The formation of apical foramen of mandibular second molars was completed at 17.11-year-age in mesial root and at 17.53-year-age in distal root. 3. The mesial root of mandibular second molar was generally developed earlier than distal root (p<0.01) 4. Coefficients of correlation and regression equations between for age(Y) and the developmental stage of mandibular second molar(X) were "Y=1.53X+6.54, r=0.91 (p<0.01)" in mesial root and "Y=1.52X+7.11, r=0.92(p<0.01)" in distal root respectively.l root respectively.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.281-286
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• 1995

Tooth length determination is a crucial step in endodontic treatment. Traditionally, radiographs are used to confirm working length of the root length. This study was performed to evaluate the radiographic distortion(magnification) and calculate correction coefficients for the object-film distance. Ninty-six radiographs were made of eight extracted teeth(two upper first premolars, two lower first premolars, two upper first molars, and two lower first molars) by using the 16 inch long cone paralelling techniques with 1mm interval from 5 to 16mm tooth-film distance. The results were as follows. 1. The least mean radiographic distortion from 5 to 16mm tooth-film distance was 2.42±0.68％(the length of mesiobuccal cusp-mesial root of lower first molars), the greatest distortion was 4.74±1.36％(the length of mesiobuccal cusp-mesiobuccal root of upper first molars). 2. The greatest correction coefficient was 0.986(the mesiobuccal cusp-mesial root of lower first molars, the lowest one was 0.937(the mesiobuccal cusp-mesiobuccal root of upper first molars).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.3
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• pp.63-67
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• 1980

This study was carried out to seek the visible marker and make it easy to select the individuals or lines which have excellent characters. Ginseng plants of one to five years were used for this study, and agronomic characters, such as stem diameter. stem length, leaf length, leaf width, petiole length. stem weight, leaf weight, number of leaves, number of leaflets, main root length, root length, root diameter and root weight were determined and correlations among them were estimated. Generally, agronomic characters, such as stem diameter, leaf length, leaf width, number of leaves, number of leaflets, leaf weight and stem weight had positive and highly significant correlations with root weight per plant, the character that has great influence on yield.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.289-299
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• 1996

It is necessary to measure the length of a root canal in order to attain a satisfactory prognosis after root canal therapy. There are several methods for determining root canal length, such as tactile sensation by the dental practitioner, the utilization of x-ray film, and electronic root canal measurement. Among these, the electrical measurement methods, in which the impedence between the oral mucous membrane and periodontal membrane is determined, have advantages of simplicity and accuracy. During root canal treatment, the root canal contains a solution of high electrical conductivity such as pus, blood, sodium hypochlorite and so on. Recently a new electronic root canal measurement device of frequency-dependent type has been developed, which is capable of measuring the length of root canal under moist conditions. Endex and Root ZX, which are frequency-dependent type, were evaluated for accuracy of measuring root canal length in vivo by stereomicroscope. The result were as follows ; 1. 82.5% of Endex and 87.5% of Root ZX measured in the range of ${\pm}0.5$ mm from the apical foramen and both showed 57.5 % in the range of 0.1 mm to 0.5 mm. 2. Endex showed significantly higher accuracy in vital teeth than nonvital teeth(p<0.05). But in case of Root ZX, there was no significant difference between vital and nonvital teeth. 3. As a result of this study, there was no significant difference in accuracy between Endex and Root ZX, and both devices showed file passes the apical foramen in more than half of the cases, and it is thought that this must be considered clinically.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.13
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• pp.77-81
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• 1973

The experiment was carried out to make clear the root characters and relationships among some quantitative characters of soybeans. The results obtained are summarized as follows: 1. Stem diameter was shown the greater growing in thickness after one month from sowing than the earlier stage, and the greater growing was shown in fertile bed soil than in sand soil. 2. The elongation of plant top in soybean plant was also shown the greater rate in bed soil than in sand soil 3. The length of plant root was longer than the length of plant top in the earlier stage of growing, and the length of root was much greater in sand soil than in fertile bed soil. 4. Weight of plant top was shown more in bed soil than in sand soil, but this tendency was shown more greater rate in the length of plant top than in weight of plant top. 5. Weight of root was more compared with weight of plant top in the earlier stage of growth, and also more greater rate was shown in sand soil than in fertile bed soil. 6. Highly significant correlations were shown among five quantitative characters, namely stem diameter, length of top, weight of top, length of root and weight of root, etc.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.1-8
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• 2021

A series of pot experiments were conducted to quantitatively estimate inhibitory effects of reclaimed soil on the growth of Lentil (Lens culinaris) with two soils remediated by land farming (DDC) and low temperature thermal desorption(YJ), respectively. After cultivation in a growth chamber for 8 days, plants were harvested for the analysis of 8 indices including chlorophyll-a and carotenoid in leaves, shoot fresh weight, root dry weight, root length, number of later roots, specific root length (SRL) as well as germination rate in comparison to control experiment conducted on nursery soil. Root length was estimated by SmartRoot program from the digital images of the roots. The results showed germination rate on YJ and DDC soil decreased 29 and 71%, respectively. In comparison to the control, the averaged value of the 8 indices for YJ and DDC soil showed overall growth inhibition was 48 and 68%, respectively. When the same experiment was conducted with 25% (W/W) vermiculate amended soil, plant growth on each soil was comparable to that of the control. The results implies reclaimed soils requires additional processes and/or amendments to reuse for plant growth.

• Journal of Soil and Groundwater Environment
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• v.24 no.5
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• pp.1-10
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• 2019

The effects of liquid phase ozonation on seed dormant alleviation and subsequent seedling growth were studied using two plant seeds of Indian jointvetch (Aeschynomene indica L.) and Indian mallow (Abutilon avicennae Gaertn.). At a constant ozone concentration ($80g/m^3$), contact time varied from 10 to 60 min with 10 min interval. Germination rate, root length, and specific root length were compared after 3-day incubation on gel-medium. The germination rate increased significantly (p<0.05) in the 50 min treatment of Indian mallow by 30% compared to the control. Enhanced root elongation was observed in the seeds of 30 min treatment of Indian jointvetch and 30~50 min treatment of Indian mallow. Specific root length, an indicator of environmental change, did not show significant changes, suggesting the level of ozone treatment has no adverse effect on seedling development. The results indicate that liquid phase seed ozonation can be an effective on-site germination alleviation method in the application of phytoremediation.

• Restorative Dentistry and Endodontics
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• v.38 no.2
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• pp.59-64
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• 2013

Apical surgery cuts off the apical root and the crown-to-root ratio becomes unfavorable. Crown-to-root ratio has been applied to periodontally compromised teeth. Apical root resection is a different matter from periodontal bone loss. The purpose of this paper is to review the validity of crown-to-root ratio in the apically resected teeth. Most roots have conical shape and the root surface area of coronal part is wider than apical part of the same length. Therefore loss of alveolar bone support from apical resection is much less than its linear length.The maximum stress from mastication concentrates on the cervical area and the minimum stress was found on the apical 1/3 area. Therefore apical root resection is not so harmful as periodontal bone loss. Osteotomy for apical resection reduces longitudinal width of the buccal bone and increases the risk of endo-perio communication which leads to failure. Endodontic microsurgery is able to realize 0 degree or shallow bevel and precise length of root resection, and minimize the longitudinal width of osteotomy. The crown-to-root ratio is not valid in evaluating the prosthodontic prognosis of the apically resected teeth. Accurate execution of endodontic microsurgery to preserve the buccal bone is essential to avoid endo-perio communication.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.134-138
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• 2000

Most parts of alfalfa plant have been reported to contain autotoxic substances that inhibit seed germination and early seedling growth, however, the chemical(s) is not still studied much. Effect of seed leachates of 'Vernal' alfalfa (Medicago sativa L.) was evaluated for inhibition of alfalfa germination and root growth through bioassay. Alfalfa seeds were extracted in 1 L deionized water for 1 h after soaking and the leachates caused to reduce root length of alfalfa significantly as the soaking time increased. Crude seeds at 4 g L$L^{-1}$ exudated autotoxins that reduce significantly root length by 34 % compared to the control, when the seeds soaked in deionized water for 24 h. However, the extracts did not affect final germination as well as speed of germination. Extracts from ground seeds significantly reduced speed of germination (GT 50) and root length. The results indicate that release of autotoxic substances from seeds during seed imbibition was increased with increase of soaking time and seed amount, and that autotoxicity was more occurred in ground seeds than in crude seeds.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.435-459
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• 1998

In order to achieve a successful endodontic treatment, root canals must be obturated three-dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora/sup (R)/(digital imaging system) and Root ZX/sup (R)/(the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems. whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with #15, #20, #25 files by 3 different dentists each using the periapical radiography. Digora/sup (R)/ and Root ZX/sup (R)/. The measurements were then compared with the true length. The results were as follows: 1. In comparing mean discrepancies between measurements obtained by using periapical radiography(mean error: -0.449±0.444 mm), Digora/sup (R)/(mean error: -0.417±0.415 mm) and Root ZX/sup (R)/(mean error: 0.123±0.458 mm) with true length. periapical radiography and Digora/sup (R)/ system had statistically significant differences(p<0.05) in most cases while Root ZX/sup (R)/ showed none(p>0.05). 2. By subtracting values obtained by using periapical radiography, Digora/sup (R)/ and Root ZX/sup (R)/ from the true length and making a distribution table of their absolute values. the following analysis was possible. In the case of periapical film. 140 out of 261<53.6％) were clinically acceptable satisfying the margin of error of less than 0.5 mm. 151 out of 261 (53,6％) were acceptable in the Digora/sup (R)/ system while Root ZX/sup (R)/ had 197 out of 261(75.5％) within the limits of 0.5mm margin of error. 3. In determining whether the thickness of files has any effect on measuring methoths, no statistically significant differences were found(p>0.05). 4. In comparing data obtained from these methods in order to evaluate the difference among measuring methods, there was no statistically significant difference between periapical radiography and Digora/sup (R)/ system(p>0.05), but there was statistically significant difference between Root ZX/sup (R)/ and periapical radiography(p<0.05). Also there was statistically significant difference between Root ZX/sup (R)/ and Digora/sup (R)/ system(p<0.05). In conclusion, Root ZX/sup (R)/ was more accurate when compared with the Digora/sup (R)/ system and periapical radiography and seems to be more effective clinically in determining root canal length. But Root ZX/sup (R)/ has its limits in determining root morphology and number of roots and its accuracy becomes questionable when apical foramen is open due to unknown reasons. Therefore the combined use of Root ZX/sup (R)/ and the periapical radiography are mandatory. Digora/sup (R)/ system seems to be more effective when periapical radiographs are needed in a short period of time because of its short processing time and less exposure.