CBCT 및 3D CT를 활용한 상악 유구치 치근과 근관 형태

김준희,김현태,신터전,현홍근,김영재,김정욱,장기택,송지수,Kim, Joon Hee,Kim, Hyuntae,Shin, Teo Jeon,Hyun, Hong-Keun,Kim, Young-Jae,Kim, Jung-Wook,Jang, Ki-Taeg,Song, Ji-Soo 대한소아치과학회 2021 大韓小兒齒科學會誌 Vol.48 No.4

이 연구의 목적은 상악 유구치의 치근 및 근관의 형태학적 특성을 분석하는 것이다. 2006년 1월부터 2020년 4월까지 서울대학교 치과병원에서 CBCT 및 3D CT를 촬영한 3 - 7세 환자 총 268명(남자 175명, 여자 93명)이 연구에 포함되었으며, 치근 흡수와 치수병변이 없는 총 1002개의 상악 유구치의 치근과 근관 수를 분석하였다. 218개의 치아에 대해 치근과 근관의 형태, 이개각도, 치근과 근관의 길이 및 근관의 단면 형태를 분석하였다. 48개의 치아에 대해서는 Mimics 및 3-Matics software를 사용하여 치근 치수의 부피와 표면적, 치근-치수 비를 측정하였다. 절반 이상이 3개의 치근과 3개의 근관을 가지고 있었다. 좌우측 치아의 대칭성(Cohen's kappa coefficient)은 약 0.63이었다. 치근과 근관의 형태는 상악 제1유구치에서는 직선형이, 제2유구치에서는 곡선형이 많이 관찰되었다. 치근의 이개 정도, 치근과 근관의 길이는 상악 제1, 2유구치 모두 구개측 치근에서 가장 크게 나타났다. 근단부에서 근관의 단면 형태는 주로 ovoid 혹은 round형이었다. 치근 치수의 부피와 표면적, 치근-치수 비는 상악 제1,2유구치 모두 구개측 치근 치수에서 가장 크게 나타났다. The purpose of this study is to analyze morphological characteristics of maxillary primary molar's root and root canal. 268 children aged 3 - 7 years (175 boys, 93 girls) who had CBCT (152 children) and 3D CT (116 children) taken in Seoul National University Dental Hospital from January 2006 to April 2020 were included. The number of roots and root canals were analyzed in 1002 teeth without any root resorption or periapical pathologies. Curvature, angulation, length of root and root canal, as well as cross-sectional shapes of the root canal were analyzed in 218 teeth. By using Mimics and 3-Matics software, volume, surface area, and volume ratio of root canal was analyzed in 48 teeth. More than half of maxillary primary molars have 3 roots and 3 root canals. The degree of symmetry of root canal type was about 0.63 (Cohen's kappa coefficient). The most frequent shape of roots and canals was linear in 1^st primary molars and curved in 2^nd primary molars. Angulation, length of root and root canals was the largest on palatal roots. Most teeth showed ovoid or round shapes at apex. The largest root canal volume, surface area, volume ratio was found in the palatal roots.

Root Characteristics and Its Influences on Shear Strength in Burned Areas

( Xiewen Hu ),( Yiteng Hou ),( Yan Wang ),( Ying Yang ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

As the typical source of debris flow after fire, the initiation of shallow surface landslides was closely linked to the change of root characteristics in fire affected soil. In order to study the influence of fire on soil strength, a series of tensile tests and direct shear tests were conducted to compare the differences of soil properties in burned and unburned area on root system and soil shear strength, using the root and soil sample obtained in burned area of Zhengdou Township, Xiangcheng County, Sichuan Province. As a consequence, the number of roots, root diameter, root mass density and root length density in the superficial soil of burned area decreased in contrast to unburned soil, in which decreased by 23.15%, 51.35%, 62.98% and 29.10% separately. The tensile force of single root inversely linked to root diameter, while the tensile strength behaved in the opposite way. The tensile force and strength in burned area was smaller than that in unburned area when it comes to the same root diameter. Laboratory shear tests shown a smaller shear strength in burned soil comparing to that of unburned soil. Compared with unburned root-soil composite, cohesion force of burned root-soil composite decreased due to root weaken, but internal friction angle behaved little change. This research shown a strength decrease of root soil composite due to weaken of root system in burned soil, and help to get more understanding of the initiation mechanism of shallow surface landslide in burned area.

치근절제술을 이용한 구치부의 치료

이선경,지숙,방은경,Lee, Sun-Kyoung,Ji, Suk,Pang, Eun-Kyoung 대한치주과학회 2008 Journal of Periodontal & Implant Science Vol.38 No.1

Purpose: Studies reported controversial results about prognosis of root resection with 0%-38% failure rate. The purpose of this study is to consider clinical efficacy of root resection. Materials and Methods: This study reported three cases of root resection which were performed on different sites. In first case, lower right first molar showed pus discharge and 7 mm of probing pocket depth. It was diagnosed as fracture of mesial root. Hemisection of mesial root was performed. In second case, upper right first molar showed severe bone loss on disto-buccal root and 7 mm of probing pocket. Resection of disto-buccal root was performed In third case, lower left second molar showed severe bone loss on distal root including apex and 15mm of probing pocket depth. Hemisection of distal root was performed. Result: In these three cases of root resection, compromised molars were treated successfully and conserved. Conclusion: Root resection is a successful procedure treating compromised multi-rooted teeth and conserving teeth when proper case selection is performed.

염화암모늄 전해질에 포함된 퀴논 레독스 활물질 조합을 이용한 수계 레독스 흐름 전지 성능 평가

이원미,정건용,권용재 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.2

In this study, anthraquinone-2,7-disulfonic acid (2,7-AQDS) is used as negative active material and Tiron is used as positive active material for aqueous redox flow battery (RFB). In previous results that used the 2,7-AQDS and Tiron, sulfuric acid (H2SO4) was a supporting electrolyte. However, in this study, ammonium chloride (NH4Cl) is suggested as the electrolyte for the first time. By changing the supporting electrolyte from H2SO4 to NH4Cl, the cell voltage of RFB is improved from 0.76 V to 1.01 V. To investigate the effect of NH4Cl supporting electrolyte of the performance of RFB, the full-cell tests of RFB using 2,7-AQDS and Tiron that are dissolved in NH4Cl supporting electrolyte are carried out, while cut-off voltage range is a main parameter to determine their performance. When the cut-off voltage range is 0.2~1.6 V, the hydrogen evolution occurs during charging step. To address the side reaction effect, the cut-off voltage range is changed to 0.2~1.2 V. When the revised cut-off voltage range is used and the current density of 40 mA/cm2 is applied, hydrogen evolution is not observed and the optimal RFB shows the charge efficiency of 99% and discharge capacity of 3.3 Ah/L at 10cycle. 본 연구에서는 Anthraquinone-2,7-disulfonic acid (2,7-AQDS)와 Tiron을 수계 레독스 흐름 전지 음극 및 양극 활물질로 사용하며 기존의 황산 전해질 대신 중성인 염화암모늄 (NH4Cl)을 전해질로 도입하였다. 이렇게 전해질을 변경함으로써, 황산 전해질의 낮은 셀 전압(0.76 V)을 1.01 V까지 향상시킬수 있다. 성능 최적화를 위해 염화암모늄 전해질에0.1M로 활물질 농도를 맞춰 컷-오프 전압에 변화를 주며 완전지셀 성능을 평가하였다. 0.2~1.6 V 구간의 컷-오프 전압으로 40 mA/cm2하에서 20 사이클 동안 완전지셀을 테스트한 결과, 충전 동안 수소가 발생하였다. 이에 컷-오프 전압 조절로 충전 전압을 낮춰서 수소 발생을 제한하고자 0.2~1.2 V 구간으로 40 mA/cm2하에서 완전지셀 테스트를 진행하였다. 수소 발생은 없었으며, 전류 효율 99%, 방전 용량 3.3 Ah/L의 성능을 보였다.

Rooting Characteristics of Stem Tip Cuttings in Ardisia pusilla as Influenced by Cutting Stage, Rooting Medium, Temperature, and Plant Growth Regulator Pretreatment

Chang Hee Lee,Oh Keun Kwon,Young Jin Kim 한국원예학회 2005 Horticulture, Environment, and Biotechnology Vol.46 No.3

To produce commercially acceptable pot plants of Ardisia pusilla, vegetative propagation method such as stem tip cutting has been used in general. Thus, the production of uniform and vigorous rooted cuttings is required. This study was conducted to screen an adequate stem tip cutting stage for rooting, to select an adequate rooting medium, to find its favoring temperature for rooting, and to develop a suitable method for promoting root development. The stages of stem tip cuttings could be divided into five groups by the degree of leaf expansion and chlorophyll contents. Stem tip cutting with green leaves was found to be the best rooting potential among the five types of stem tip cuttings. In rooting medium, roots dry weight showed 152% increase in only vermiculite compared to in a commercial growing medium (perlite:peatmoss=1:1, v/v). Rooted cuttings of A. pusilla showed very sensitive rooting potential according to temperature and optimal rooting temperature was found to be 20-25℃. Although indole-3-butyric acid (IBA) used for rooting increased the number of roots in a concentration-dependent manner regardless of the pretreating methods, dipping treatment into a 1500 ㎎ㆍℓ?¹ IBA solution for 10 min was the most effective on increasing the number of roots. However, cuttings treated with 0.4% naphthylacetamide (NAA) talc showed the heaviest root dry weight than those with the other treatments. Thus, NAA talc was the most acceptable rooting promotion method for producing rooted cuttings due to simple and practical method used by farmers. In conclusion, rooting characteristics of cuttings in A. pusilla was very dependent on cutting stage, rooting medium, and rooting temperature.

江原道 소나무林의 特性에 관한 綜合的 硏究(Ⅲ) : 江原大學校 構內林의 根系 形態와 分布에 대하여 Studies on the Tree-Root Form and Distribution on the Campus Forest, Kangwon Nat'l Univ.

吳在萬,全槿雨 江源大學校 林科大學 森林科學硏究所 1994 Journal of Forest Science Vol.10 No.-

樹木의 뿌리는 樹木의 生長과 土壤의 構造改善에 밀접한 관계가 있음에도 불구하고 地下部에 위치하고 있으므로 연구가 미진한 상태이다. 따라서 각 樹種의 根系의 발달상태를 파악하는 것은 그 樹種의 특성 파악과 뿌리가 地表固定에 미치는 영향을 파악하는 데 기초자료로 활용할 수 있다. 본 연구에서는 江原道 소나무林의 특성을 파악하기 위한 기초연구의 일부로서 일차적으로 江原大學校 構內 소나무林의 根系의 形態 및 分布에 대하여 규명하였다. 5개의 供試木에 대해 조사한 결과 뿌리의 形態는 水平根이 잘 발달되어 있었다. 뿌리의 分布에 있어서 크기별로는 細根은 대부분이 点在(+)하고 있었으며, 太根은 0.2㎝가 대부분이었다. 깊이별로는 太根, 細根 모두가 10∼30㎝에서 60∼70% 이상 집중되었으며, 太根은 주로 0.9㎝ 이하였고, 細根은 대부분이 点在(+)하고 있었다. Because of the underground existence of roots, a few studies have been reported on root system. The developmental information of roots should be understood for the studies of specific tree traits and the influence of such traits on the soil surface fixation. In order to clarify the specific character of pine forest in Kangwon Province, the investigation on the form and distribution of root system of pine trees were carried out for 5 trees in the Campus Forest, Kangwon National Univ.. Root form was very well in flat root. As soil depth was approximatly 50㎝, fine roots were very sparsly distributed(+), roots of 0.2㎝ in diameter were most common and roots > 0.2㎝ were very rare, also thickness thined. 60∼70% all the roots were developed at the depth of 0∼30㎝, where big roots were below 0.9㎝ in diameter and fine roots were higly sparse(+).

토양 산성화에 따른 소나무(Pinus densiflora Sieb. et Zucc.)의 뿌리 적응성에 관한 연구

이도형 ( Lee Do Hyeong ) 한국산림과학회 2004 한국산림과학회지 Vol.93 No.1

This study was conducted to investigate the relationship of development of root and soil condition and also to elucidate mechanical and physical stability according to distribution of roots of Pinus denszflora S. et 2. natural stands of 35 to 45 years of age with different soil pH condition. The average tree age in Gyeongsan stand was 42 years old which was 5 years older than that of Uljin stand, however average tree height in Gyeongsan stand(ll.7m) was lower than that of Uljin stand(l8.6m). In the root structure, remarkably different root pattern was shown between the two stands. Uljin stand showed longer in the total length of root than Gyeongsan stand and the ratio between length of horizontal and vertical root was almost same in Uljin stand, while Gyeongsan stand showed comparatively higher value in the horizontal roots. In total weight of root. Uljin stand showed much higher value(75.13kg) than Gyeongsan stand (41.28㎏) and the amount of thin root was also showed higher value in Uljin stand(7.34㎏) than Gyeongsan stand(l.23㎏). In root development by soil depth, most of roots developed much more deeply into soil in Uljin stand than in Gyeongsan stand. As a result of analysis of the growth ring of the root, Uljin stand showed better root growth than that of Gyeongsan stand. In Gyeongsan stand having pH value(4.45). much modified roots, the abnormal root branch form such as fork, gun and rake type were appeared and it seemed to be attributed by the soil acidification. In conclusion, the root development pattern of Pinus densziflra is likely adapted to the soil condition especially acidification of soil and this caused in various modified roots. The pattern of root structure in the acidified soil was being adapted from well developed vertical root system to horizontal root system with small number of roots and these modified root structure will result in the reduction of growth and the resistance against wind, drought and pests of Pinus dmYhra stand.

The changes of root length and form in immature teeth after orthodontic treatment

Kim,Hyeon-A,Park, Soo-Byung 대한치과교정학회 2004 대한치과교정학회지 Vol.34 No.3

교정치료에 대한 인지도 변화 및 보호자의 관심증가로 조기에 내원하는 환자가 많으며 그 중 일부가 전치부 치근첨이 완성되기 전인 10세 이전에 고정식 교정장치가 필요하게 된다. 따라서 본 연구에서는 미완성 치근의 치료 전후 치근의 길이 변화를 측정하고 형태변화를 관찰하여 완성된 치근의 교정력에 의한 변화양상과 비교하고, 환자의 성별, 기간, 이동양상 등과의 연관성을 조사하였다. 상악의 전치부 치근첨이 완성되지 않은 상태에서 고정식 교정치료를 시작한 8~10세 환자 28명을 실험군으로 하고, 치근첨이 완성된 상태에서 고정식 교정치료를 시작한 11~15세 환자 31명을 대조군으로 삼았다. 상악 4전치의 치료 전후 치근단 방사선사진상에서 치관, 치근길이를 측정해서, 치근길이의 변화량, 치관/치근 비의 변화량을 계산했고 분류체계에 따라 치근형태에 점수를 부여했다. 결과는 다음과 같다. 1. 대부분의 미완성 치근은 교정치료 후에도 치근 길이가 증가하였으며 정상적인 치근첨 형태를 보였다. 2. 치료기간이 길어지거나 개방교합의 경우, 미완성 치근이라도 치근길이가 증가하지 않거나 더 짧아진 경우도 있었으며 정상적인 길이가 되더라도 치근첨의 완성 형태가 뭉툭한 흡수 형태를 보였다. 3. 완성치근에서는 교정치료에 의하여 대부분의 치근이 경미한 치근흡수를 보였으며, 흡수된 치근첨의 형태는 미완성 치근의 완성 형태보다 더 뭉툭하였다(p<0.05). 4. 미완성 치근에서는 치료기간과, 완성치근에서는 치아의 이동거리(Ul to facial plane의 변화량)와 유의한 상관관계를 보였다(p<0.05). 5. 미완성 치근, 완성치근 모두 성별. 부정교합 분류, 수직피개의 변화량, 두개저에 대한 치아의 위치 변화(U1 to SN의 변화량)등과는 유의한 상관관계를 보이지 않았다. Previous studies have focused on the causes of root resorption after orthodontic treatment and treatment methods to reduce this phenomenon, and have been mainly associated with developed, mature roots. As parents become increasingly interested in their children's' dentition, orthodontists are performing fixed orthodontic treatment on patients of less than 10 years and before the completion of the immature root. Thus, the author evaluated the changes of root length and root form of maxillary immature incisors after orthodontic treatment, compared with those of mature teeth, and investigated the correlation according to gender, treatment duration, and displacement of incisors. The sample consisted of an immature root group of twenty-eight persons (between 8 and 10 years old) and a mature root group of thirty-one persons (between 11 and 15 years old). The crown and root length of the maxillary four incisors were measured with a periapical radiograph, changes in root length and crown-root ratio were calculated, and root form was classified according to a scoring system. The results were as follows. 1. The development of immature roots was not affected by orthodontic treatment and mostly showed normal root length and apical form. 2. Root length of immature teeth was sustained or became shorter, partially in long treatment duration or with open bite patients. Even though the teeth reached their normal root length, they demonstrated a blunt form. 3. Most of the mature roots showed mild resorption, and the form of mature roots was more blunt than the developed form of the immature roots (p<0.05). 4. The developed form of the immature roots was statistically related to treatment duration, while the form of the mature roots was significantly related to the displacement of incisors (p<0.05). 5. In contrast, other variables such as gender, classification of malocclusion, changes in overbite, and changes of U1 to SN showed no correlation with the root resorption of both groups.

협설만곡치아의 파노라마방사선영상소견에 대한 연구

김영호,정환석,허경회,이원진,허민석,이삼선,최순철,Kim, Young-Ho,Jeong, Hwan-Seok,Huh, Kyung-Hoe,Yi, Won-Jin,Heo, Min-Suk,Lee, Sam-Sun,Choi, Soon-Chul 대한영상치의학회 2010 Imaging Science in Dentistry Vol.40 No.1

Purpose : We want to identify the appearance of the buccolingual root dilaceration teeth in the panoramic views and specify the characteristics of these teeth. Materials and Methods : One thousand-six patients were examined on the basis of both panoramic and CT image criteria. We diagnosed and excluded certain teeth from the samples; both prosthodontic or pathologic lesion appearing teeth and mesiodistally dilacerated ones. We meticulously discerned buccolingually dilacerated teeth in the CT images and total 48 samples were selected. The degree of severity in dilaceration was standardized by 2 types of criteria. The samples were differentiated into 3 groups and again categorized into six types showing from the panoramic views: irregular view on the root apex area, clear blunt on the root tip, stepping on root tip, double lamina dura or double tip, arrow-target shaped root, bull's eye, normal view. Results : The types of teeth selected from total 48 buccolingual root dilaceration samples were mandibular first and second molar, premolars, canines, and lateral incisors. The direction of dilaceration was an even percentage to each buccal and lingual side for most selected teeth, however, that of both canines and lateral incisors were directed in almost a buccal side. In the panoramic views, the root types of the buccolingually dilacerated teeth were irregular view on the root apex area, clear blunt on the root tip, stepping on root tip and normal types were almost always normal view. The more severity in dilareated degree, the more chances of observation in the panoramic views were clear blunt on the root tip and stepping on root tip. Conclusion : As observed in the shape of stepping on root tip or double lamina dura in the panoramic views, there can be much more probability to diagnose as a buccolingually dilacerated root.

딸기의 뿌리 및 지상부 생육에 미치는 근부온도의 영향

전하준(Ha Joon Jun),황진규(Jin Gyu Hwang),손미자(Mi Ja Son),최동진(Dong Jin Choi) (사)한국생물환경조절학회 2008 생물환경조절학회지 Vol.17 No.1

저온기의 딸기 재배를 위한 기초자료를 얻기 위하여 ‘아키히메(章姬)’품종을 재료로 딸기의 뿌리 발달에 미치는 저온의 영향과 지하부의 온도와 관련된 지상부의 생육을 조사하였다. 18℃의 근온처리구에서 1차근의 생육이 가장 양호하였으며 8℃의 저온에서 뿌리의 신장률이 가장 낮았으며, 특히 측근의 수와 길이가 가장 저조하였다. 근부의 온도는 지상부의 생육에도 직접적인 영향을 미쳐서, 낮은 근권 온도에서는 지상부의 생체중, 엽면적, 엽장, 엽폭 및 엽수의 저하를 초래하였다. 본 실험의 결과는 지하부 온도관리의 중요성을 확인할 수 있는 것으로 딸기 촉성재배농가에 유용한 정보로 활용될 수 있을 것이다. The experiment was investigated the effects of lower root zone temperature on shoot and root growth of ‘Akihime’ strawberries in aeroponics in cold season. Root growth was decreased with decrease of root zone temperature, especially in lateral roots. Elongation of main roots was highest in 18℃ of root zone temperature. Number of lateral roots and length of lateral roots were lowest in 8℃ of root zone temperature. Lower root zone temperature resulted significantly in decrease of fresh weight of root and shoot and leaf area of strawberry. But there were no significant statistical differences in shoot fresh weight and leaf area in 8℃ and 13℃of root zone temperature. Leaf length, leaf width and number of leaves of strawberry were decreased in lower root zone temperature. The results of this experiment will be utilized in the winter season cultivation for strawberry in hydroponics.