• Restorative Dentistry and Endodontics
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• 제30권1호
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• pp.31-37
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• 2005

본 실험은 resin 시편을 이용하여 미리 제작한 근관 내 불규칙 확장부에서 근관 충전용 sealer의 적용 방법에 따른 충전 효과를 평가해 보았다. Endo-training Bloc을 절단하여 사십 개의 규격화된 resin 블록 시편을 획득하였다. 각각의 시편에 $\#20$, 08taper GT 파일을 사용하여 근관을 형성하였고 근관에 손상이 가지 않도록 시편을 양분한 후 양분된 시편의 한 쪽 근관 벽에 다양한 근관 내 확장부를 표현하는 구를 형성하였다. 양분된 시편을 결찰하고 절단 부위를 밀봉하였으며 AH26 sealer를 사용하여 단일 cone 충전법으로 근관을 충전하였다. 네 가지의 근관 충전용 sealer의 적용방법을 이용하였다: A군, $\#20$ K-file : B군, ultrasonic file : C군, lentulo spiral: D군. EZ-Fill bi-directioanl spiral. 모든 시편은 $37^{\circ}\;100\%$ 상대습도에서 1주일간 보관한 후 각 시편을 근단에서 3mm, 4mm, 5mm 부위에서 수평으로 절단하고 각각의 절단면을 위상차현미경과 디지털 카메라를 이용하여 30배율로 관찰하고 촬영하였다. 관찰된 절단면은 scoring system을 이용하여 점수를 산정하였고 각 군 간의 통계적인 유의성 유무는 Fisher's Exact Test를 이용하여 시행하였다.

• The Korean Journal of Pain
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• 제11권1호
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• pp.101-104
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• 1998

Backgrouds: Twent five years have passed since the opening of the first pain clinic in korea, in 1973 at Yonsei University Hospital. The number of pain clinics are gradually increasing in recent times. It is important to plan for future pain clinics with emphasis on improving the quality of pain management. Therefore we reviewed the patients in our hospital to help us in planning for the future of our pain clinic. Methods: We analyzed 2656 patients who had visited our Kim Chan Pain Clinic, accordance to age, sex, disease, and type of treatment block, from July 1996 to August 1997. Results: The prevalent age group was in the fifties, 27.3%, seventy years and older compromised 9.2%. The most common disease were as follows: lower back pain(46.2%); cervical and upper extremities pain(23.1%); trigeminal neuralgia(7.2%); and hyperhydrosis(5.8%) Both nerve blocks and medication were prescribed as treatment. Lumbar epidural block(16.3%) and stellate ganglion block(15.6%) were the most frequent blocks performed among various nerve blocks. Among nerve block under C-arm guidance, lumbar facet joint block(24.4%) and lumbar root block(22.5%) were performed most frequently. Trigeminal nerve block(18.4%), thoracic(17.0%) and lumbar sympathetic ganglion block(11.4%) were next most prevalent blocks performed frequent block. Conclusions: Treatments at our hospital were focused on nerve blocks and medications prescriptions. Nerve blocks are of particular importance in the diagnosis and treatment of chronic pain. However in future, to raise the quality of pain management, we need to fucus on a multidisciplinary/interdisciplinary team approach.

• Restorative Dentistry and Endodontics
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• 제27권4호
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• pp.421-431
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• 2002

C-shaped canal configuration is very difficult to treat because that clues about preoperative canal anatomy cannot be ascertained from clinical crown morphology and limited information can be derived from radiographic examination. This study was done to get more informations about the root and canal configuration of C-shape root by 3-dimensionally reconstructing for the purpose of enhancing success rate of endodontic treatment. 30 mandibular molars with C-shaped root were selected. Six photo images from occlusal, apical, mesial, distal, buccal, lingual directions and radiographic view were taken as preoperative ones to compare them with 3-D image. After crown reduction to the level of 1-2mm over pulpal floor was performed, teeth were stored in 5.25% sodium hypochlorite solution for the removal of pulp tissue and debris. They were cleaned under running water, allowed to bench dry and embedded in a self-curing resin. This resin block was serially ground with a microtome (Accutom-50, Struers, Denmark) and the image of each level was recorded by digital camera (FinePix S1-pro, Fuji Co., Japan). The thickness of each section was 0.25mm. Photographs of serial sections through all root canal were digitized using Adobe Photoshop 5.0 and then minimum thickness of open and closed sites were measured (open site is the surface containing occluso-apical groove closed site is oppsite). After dizitization using 3-D Doctor (Able software Corp, USA). 3D reconstruction of the outer surface of tooth and the inner surface of pulp space was made. Canal classsification of C-shaped roots was performed from this 3-D reconstructed image. The results were as follows : 1. Most C-shape rooted teeth showed lingual groove (28/30). 2 According to Vertuccis' calssification, type I, II, III, IV, VII were observed. but also new canal types suck as 2-3-2, 1-2-3-2. 2-3-2-1, 2-3-2-3 were shown. 3 There was little difference in minimum thickness on coronal and apical portions, but open site were thinner than closed site on mid portion. Conclusively, 3D reconstruction method could make the exact configurations of C-shape root possible to be visualized and analyzed from multi-directions. Data from minimum thickness recommend cleaning and shaping be more carefully done on dangerous mid portion.

• 대한조선학회지
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• 제12권2호
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• pp.35-42
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• 1975

This paper investigates the distribution of stress and its behavior at the Root Toe in fillet welding joint. Furthermore, the stress components and principal stresses in the fillet welds are calculated by the finite element method. The distribution of stresses obtained numerically by means of the finite element method is also compared with the experimental results of two dimensional photoelasticity. A Cover plate type and Center block type of fillet welds are used as models for the numerical calculations covering the variations of 2 W/M(thickness of main plate/thickness of cover plate)=1 through 2W/M=4. The results obtained in these studies are summarized as follows; 1) When W2/M values become small, the stress concentration factors of the Root are larger than of the Toe in a C-type. Its critical value is 2W/M=3.00. However, no critical value exists in a T-type. 2) For 2W/M Values being avove 3.5 in a C-type and above 4.0 in a T-type, $K_R$ and $K_{\tau}$ become 1. 3) According to the differences of 2W/M values, the differences in stress become increasing in the Root but become decreasing in the Toe. These differences, however, disappear as the free boundary surface is approached. 4) The stress concentration factors of both the Root and Toe obtained by means of the finite element method have somewhat lower values than obtained by the photoelasiticity. But their principal stress directions coincide in either method. 5) It proves beneficial to employ the finite element method for two-dimensional plane stress analysis in front fillet welding joint.

• Restorative Dentistry and Endodontics
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• 제32권1호
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• pp.37-46
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• 2007

C-shape 근관은 주로 하악 제 2대구치에서 보이는 해부학적 변이 형태로서, 그 특징은 각 근관을 연결하는 fin이나 web이 존재한다. 이런 해부학적으로 복잡함은 근관치료시에 세정과 성형 및 근관충전을 방해하며, 과다한 기구 조작시에 뜻하지 않는 천공을 유발하기도 한다. 이 연구의 목적은 C-shape 치근을 가진 하악 제2 대구치의 해부학적인 형태와 치근의 위치에 따른 최소 근관벽 두께에 대하여 연구하고자 하였다. 발거된 하악 대구치중 C-shape 치근을 가진 치아를 30개 선별하여 방사선 사진 및 협측, 설측, 치근단 부위를 디지털 카메라를 이용하여 촬영하였다. 자가 중합형 교정용 레진 (Orthodontics resin, Densply/Caulk, U.S.A)을 이용하여 치관부를 제거한 치아를 매몰한 후 각각의 시편을 Accutom-50 (Struers, Denmark)에 고정시켜 1 mm 간격으로 절단, 연마한 다음 절단면을 수술용현미경에 연결된 디지털 카메라 (Coolpix 995, Nikon, Tokyo, Japan)를 이용하여 각각의 상을 촬영하였다. 30개 치아에서 촬영한 197개의 치아단면을 Root thickness gauge program을 이용하여 근관형태의 변화를 분류하고 부위별 근관과 치아외벽 사이에 존재하는 상아질의 최소두께에 대해 연구 분석하였다. 1. 근관입구에서 C I이 가장 많이 (73%) 관찰되었으나 치근단부로 갈수록 근관 형태의 다양한 변화를 보여 C II와 C III의 근관형태가 많이 관찰되었으며, 11 개의 (36%)치아에서는 근관입구에서 치근단부까지 근관형태의 변화를 보이지 않았다. 근관입구에서 단지 2개의 치아에서 나타난 C III type은 치근단부로 갈수록 높은 발현빈도를 나타내었다. 2. C-shape 근관은 근관입구 부위에서는 continuous 나 semicolon canal을 가지나 치근단부로 갈수록 2개나 3개의 근관을 갖는 경우가 많다. 3.평균적인 근관과 치질사이의 최소거리는 근첨부의 설측부위에서 나타났다.

• The Journal of Advanced Prosthodontics
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• 제3권4호
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• pp.186-189
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• 2011

PURPOSE. Porcelain fused to metal (PFM) crowns provide the best treatment option for teeth that have a large or defective restoration. More than 20% of teeth with PFM crowns or bridges require non-surgical root canal treatment (NSRCT). This may be due to the effect of restorative procedures and the possible leakage of bacteria and or their by-products, which leads to the demise of the tooth pulp. Thus, this study was planned to compare the ability of the restorative materials to seal perforated PFM specimens. MATERIALS AND METHODS. The study evaluates the ability of amalgam, composite or compomer restorative materials to close perforated PFM specimen's in-vitro. Ninety PFM specimens were constructed using Ni-Cr alloys and feldspathic porcelain, and then they were divided into 3 groups: amalgam (A), composite + Exite adhesive bond (B) and compomer + Syntac adhesive bond (C). All the PFM samples were embedded in an acrylic block to provide complete sealing of the hole from the bottom side. After the aging period, each group was further divided into 3 equal subgroups according to the thermocycling period (one week for 70 cycles, one month for 300 cycles and three months for 900 cycles). Each subgroup was put into containers containing dye (Pelikan INK), one maintained at $5^{\circ}C$ and the other at $55^{\circ}C$, each cycle for 30 sec time. The data obtained was analyzed by SPSS, 2006 using one way ANOVA test and student t-test and significant difference level at (P<.01). RESULTS. The depth of dye penetration was measured at the interfaces of PFM and filling materials using Co-ordinate Vernier Microscope. The lowest levels of the dye penetration for the three groups, as well as subgroups were during the first week. The values of dye leakage had significantly increased by time intervals in subgroups A and C. CONCLUSION. It was seen that amalgam showed higher leakage than composite while compomer showed the lowest level of leakage.

• 대한치과보철학회지
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• 제41권2호
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• pp.232-242
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• 2003

Statement of problem : Fiber-reinforced posts have lower modulus of elasticity than titanium post or cast post-core. With this similar elasticity to that of dentin, fiber-reinforced posts have been known to have a tendency to reduce the risk of root fracture. However, there were few studies on the teeth restored with fiber-reinforced posts under the condition of reduced periodontal support. Purpose : The purpose of this study was to evaluate the fracture strength and failure mode of endodontically treated teeth restored with fiber-reinforced posts and titanium posts under the condition of reduced periodontal support. Material and method : Extracted human maxillary incisor roots were divided into 3 groups (group 1 carbon fiber post, group 2 : glass fiber post, and group 3 : titanium alloy post). After coronectomy and endodontic treatment, teeth were restored with each post systems and resin core according to the manufacturer's recommendation. Then, teeth with simulated periodontal ligament were embedded in the acrylic resin blocks at the level of 4 mm below the cemento-enamel junction. Each specimen was exposed to $10^5$ load cycles with average 30 N force in $36.5^{\circ}C$ water using a computer-controlled chewing simulator. Loads were applied at $45^{\circ}$ angle to the long axis of the teeth. After cyclic loading, teeth were subjected a compressive load until failure at a crosshead speed of 0.5 mm/min. Fracture strength (N) and failure mode were examined. The fracture strength was analyzed with one-way ANOVA and the Scheffe adjustment at the 95% significance level. Results and conclusion : The results were as follows. 1. There was no statistically significant difference in the mean fracture strength among the groups (P<.05). 2. Carbon fiber post and glass fiber post group showed less root fracture tendency than control group. 3. All specimens with root fractures showed fracture lines above the level of acrylic resin block, except for only one specimen in group 3.

• 아시안잔디학회지
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• 제23권1호
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• pp.111-122
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• 2009

본 연구는 완효성 질소 성분이 함유된 복합비료의 시비가 크리핑벤드그래스 생육과 토양 중 변화에 미치는 영향을 시험하고자 2007년 7월부터 12월까지 6개월간 수행하였다. 처리구는 비료를 처리하지 않은 무처리구(NF), 속효성질소복합비료(11-5-7)를 처리한 대조구(CF), MU 질소성분이 함유된 복합비료를 처리한 처리구 1(MU), IBDU 질소성분이 함유 된 복합비료를 처리한 처리구 2(IBDU 1)과 처리구3(IBDU 2) 등 5개 처리를 난괴댑으로 수행하였다. 시비 후 속효성질소성분과 완효성질소성분의 경과시간에 따른 토양 중 변화와 염색지수와 엽록소함량과 같은 잔디품질과 잔디 생육량, 잔디밀도 등 잔디 생육을 조사하였고, 그 결과를 요약하면 아래와 같다. 암모니아태질소와 질산태질소는 모든 처리구에서 시비 후 시간이 경과함에 따라 점차증가하는 경향을 보였고, 총질소는 점차 감소하였다. 질산태질소와 총질소는 속효성 비료처리구(CF)보다는 완효성 비료 처리구(MU, IBDU 1, IBDU 2)에서 높게 나타났으며, 시비 후 경과시간에 따른 토양 중 가용성질소의 변화는 시비초기에는 속효성 비료의 가용성 질소가 많으나 시비 후 30일 정도까지는 속효성 비료와 완효성 비료의 가용성 질소 비율은 비슷하고 30일 이후에는 완효성 비료 처리구에서 가용성 질소 비율이 증가하였다. 염색지수와 엽록소함량을 NF와 비교한 결과, 엽색지수는 CF, MU, IBDU 1 및 IBDU 2에서 각각 6.5%, 6.7%, 5.9%, 5.5% 증가하였고, 엽록소함량은 33.2%, 38.4%, 35.1%, 37.1% 증가하여 MU 처리구에서 높게 나타났다. 잔디생육량은 CF, MU, IBDU 1 및 IBBU 2가 NF보다 76.2%, 77.7%, 69.5%, 72.3% 각각 높게 나타났으나 대조구와 처리구간 예초물량은 비슷하였고, 잔디밀도는 무처리구보다 비료 처리구에서 증가하였고, 속효성 비료처리구(CF)보다 완효성 비료 처리구(MU, IBDU 1, IBDU 2)에서 잔디밀도가 증가했다. 본 결과들을 통해 완효성 질소 성분함유비료가 속효성 질소에 비해 토양 중 가용성 질소의 함량을 높여 질소비효기간을 연장시키고, 염색지수와 엽록소함량은 비슷하며 예초물량은 비슷하거나 감소시키지만 잔디밀도는 향상시켜 완효성질소 함유비료의 시비가 잔디생육에 효과적인 것으로 평가되었다.

• Restorative Dentistry and Endodontics
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• 제30권5호
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• pp.385-392
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• 2005

목적은 근관충전이 상아세관 내에 남아있는 세균에 미치는 영향을 알아보고 가터퍼차와 resilon의 밀폐 능력을 상아 세관 내에 남아있는 세균의 생존 여부를 통하여 비교하는 것이다. 발치된 우전치로 치아시편에 E. faecalis를 접종하고 제 1군은 음성대조군, 제 2군은 양성대조군, 제 3군은 ZOE 계통의 근관전색제와 가터퍼차, 제 4군은 레진 계통의 근관전색제와 가터퍼차 제 5군은 레진 계통의 근관전색제와 resilon으로 근관 충전하였다. 각 시편은 1, 2, 3주 및 4주간 보관한 뒤 round bur로 근관 내를 삭제하여 얻은 상아질을 배양하고 혼탁도를 측정하였다. 1. Nail varnish로 상아세관을 완전히 밀폐한 경우, 상아세관 내의 E. faecalis의 수는 가터퍼차 및 resilon으로 근관 충전 한 경우보다 통계적으로 유의차 있게 감소하였다 (p < 0.05) .2. 레진 계통의 근관전색제와 resilon으로 근관충전 한 군에서는 시간의 흐름에 따라 상아세관 내의 E. faecalis의 수가 유의차 있게 감소하였다 (p < 0.05) 3. 가터퍼차와 resilon으로 근관충전한 군 사이에 상아세관 내에 남아있는 E. faecalis의 생존 정도는 통계학적 유의차가 없었다 (p > 0.05).

• 한국환경복원기술학회지
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• 제2권3호
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• pp.47-53
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• 1999

This study was carried out to suggest the slope revegetation technology of biological engineering using the Ligustrum obtusifolium, which is one of the pioneer plant species. Ahead of the experimental construction, we evaluated the L. obtusifolium's value of biological engineering for the slope stabilization by testing the growth rate after the cuttings were buried for 8 weeks('98. 7. ~ '98. 9.). In this test, it was found that the L. obtusifolium, one of the species deep rooted with developed underground parts, is very effective for the slope stabilization and that the rooting powder(Hormex Powder) gave the better effects on root germination. In April of 1999, the experimental construction of biological engineering technology using recycled L. obtusifolium live cuttings(applied growth-stimulating compound) and green bags was conducted at sandy cut-slope in GLEN ROSS G.C.(Yongin). The slope was tolerant of soil erosion despite of heavy rainfall in the rainy season and many plant species invading for five months('99. 4. ~ '99. 9.). The vegetation research was performed through examining the frequency of each block using the transect method. 21 kinds of plant speices appeared in total area($25.5m^2$) and the dominant species are Digitaria sanguinalis, Setaria viridis, Cyperus amuricus, Persicaria blumei, Artemisia princeps var. orientalis. With regard to life forms, therophytes were shown with a dominant distribution of 66.7% of total species and neophytes relatively with a low distribution of 19.0%. Furthermore, it can be estimated that there is no ecological stabilization of this slope with the result of the ruderal species' occupation of 71.4%. It is too early to argue about ecological mechanical advantages and disadvantages of this technology, but, from the result of this study, it is expected that the slope revegetation technology of biological engineering using L. obtusifolium can be effectively applied to sandy slope(not rock or weathered rock slope) and that the early rapid stabilization and favorable succession could be done with the improvement of soil condition.