• Geomechanics and Engineering
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• 제12권3호
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• pp.541-560
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• 2017

In this research, experimental and numerical simulations were adopted to investigate the effects of ligament angle on compressive strength and failure mode of rock-like material specimens containing two non-coplanar filled fissures under uniaxial compression. The experimental results show that with the increase of ligament angle, the compressive strength decreases to a nadir at the ligament angle of $60^{\circ}$, before increasing to the maximum at the ligament angle of $120^{\circ}$, while the elastic modulus is not obviously related to the ligament angle. The shear coalescence type easily occurred when ${\alpha}$ < ${\beta}$, although having the same degree difference between the angle of ligament and fissure. Numerical simulations using $PFC^{2D}$ were performed for flawed specimens under uniaxial compression, and the results are in good consistency with the experimental results. By analyzing the crack evolution process and parallel bond force field of rock-like material specimen containing two non-coplanar filled fissures, we can conclude that the coalescence and propagation of crack are mainly derived from parallel bond force, and the crack initiation and propagation also affect the distribution of parallel bond force. Finally, the displacement vectors in ligament region were used to identify the type of coalescence, and the results coincided with that obtained by analyzing parallel bond force field. These experimental and numerical results are expected to improve the understanding of the mechanism of flawed rock engineering structures.

• Restorative Dentistry and Endodontics
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• 제25권3호
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• pp.338-358
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• 2000

The effect of bench drying or removal of the periodontal ligament with NaOCl upon periodontal healing and root resorption after replantation of molars was studied in rats. A total of 40 Sprague-Dawley female rats were used and fed a powdered purina rat chow diet containing 0.4% beta-aminoproprionitrile. The maxillary first molars were extracted and the periodontal ligaments were removed either by bench drying for 15 minutes or by immersion in 2.5% NaOCl solution. The rats were sacrificed at 5, 10, and 21 days by heart infusion. In order to observe the effect of 0.5% stannous fluoride, $10^{-4}M$, $10^{-2}M$, and 1M etidronate disodium on the early stage of periodontal healing, the periodontal ligament was removed with 2.5% NaOCl followed by immersion of the molar in the respective solutions for 5 minutes. The rats were sacrificed after 10 days and the following results were obtained. 1. The removal of the periodontal ligament with 2.5% NaOCl seemed to be more effective than bench drying, since the resorption area in the NaOCl treated group showed a gradual increase whereas a decline in resorption area from 5 days to 21 days was observed in the bench dried group. 2. The application of 0.5% stannous fluoride seemed to enhance the periodontal ligament attachment and active migration of fibroblasts could be observed. 3. The application of $10^{-4}M$, $10^{-2}M$, and 1M etidronate disodium led to a good periodontal ligament attachment. No evident areas of root resorption were found. 4. The use of ${\beta}$-APN made it possible to extract the maxillary first molar with all five roots intact.

• Imaging Science in Dentistry
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• 제47권3호
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• pp.199-207
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• 2017

Purpose: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Materials and Methods: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Results: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Conclusion: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

• 한방재활의학과학회지
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• 제31권3호
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• pp.73-84
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• 2021

Objectives The objective of the study is to review the Korean traditional medicine treatment used in cruciate ligament injury. Methods According to patients, treatment methods, research design, evaluation tools, outcome, we searched for studies which performed Korean traditional medical treatment on patient with cruciate ligament injury. Results In 11 studies, total number of patents were 78. Patients were conducted with 11 kinds of treatment, which is acupuncture, herbal medicine, pharmacopuncture, electro-acupuncture, burning acupuncture, moxibustion, physiotherapy, exercise, Chuna and cupping. The most commonly used measurement was visual analog scale. Conclusions Throughout the study, we could organize Korean traditional medicine treatment for patient with cruciate ligament injury. However it is difficult to figure out among the 11 intervention which interventions were effective in improving symptom. Therefore, further researches like randomized clinical trial and systematic review is needed in order to enhance the evidence of the Korean traditional medicine.

• 대한정형외과학회지
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• 제56권1호
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• pp.93-97
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• 2021

인대의 석회침착은 비교적 흔히 발생하는 질병으로 주로 견관절의 회전근개에 호발하며 만성기에는 보존적 치료를 할 수도 있지만 급성기에는 수술적 가료를 요하기도 한다. 슬관절의 십자인대에서 발생하는 석회화 침착은 매우 드물게 보고되고 있으며 특히 후방십자인대 내에서 발생한 석회화 침착은 거의 없다. 저자들은 51세 여자에서 증상을 동반한 슬관절의 후방십자인대의 실질부에 발생한 석회화 1예에서 8개월간의 보존적 치료로 호전되지 않아 수술적 치료를 시행하였으며 관절경적 석회 침전물의 절제 시 인대의 심한 훼손으로 잔존 인대의 보존이 힘들어 후방십자인대 재건술을 시행하였다. 술 후 2년에 석회화 침착의 재발은 없었고 증상은 소실되었기에 이를 문헌 고찰과 함께 보고하는 바이다.

• 대한소아치과학회지
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• 제21권2호
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• pp.439-455
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• 1994

생리적 치근 흡수가 뒤따르는 유치 치주인대의 신경분포 및 변화를 평가하기 위하여 생후 1, 2. 3. 4. 5개월된 개의 유치 치주인대와 9개월된 영구치 치주인대를 대상으로 neurofilament protein(NFP) 을 이용한 면역조직화학적 방법으로 관찰하여 다음과 같은 결과를 얻었다. ${\bullet}$ 유견 유치의 치주인대 신경분포는 치근단 1/3 부위에서 가장 밀집되어 있었으며 치근 중앙부로 향할수록 현저하게 감소되었으며 전체적으로 그 분포밀도 및 분지 정도는 영구치와 비교시 약한 양상을 나타냈다. ${\bullet}$ 구치부에 비해 전치부에서 신경분포가 보다 발달된 양상을 보였으며 구치 치근이개부 치주인대에서는 신경섬유가 관찰되지 않았다. ${\bullet}$ 유치근이 흡수됨에 따라 신경분포 정도도 감소되었으며 탈락시기의 치근 주위에서는 신경섬유를 관찰할 수 없었다. ${\bullet}$ 치은점막상피의 신경지배는 치아가 발육함에 따라 감소되는 양상을 나타내었으며 설측점막이 순측점막보다 더 발달된 신경분포 양상을 관찰할 수 있었다. ${\bullet}$ 유치 치주인대 신경말단 형태는 수지상의 신경말단 형태를 나타내고 있었으며 전형적인 Ruffini 신경말단은 거의 관찰할 수 없었다. 이상의 결과를 미루어 신경섬유의 분포는 기능과 밀접한 관계가 있는 것으로 생각되고 더우기 유치의 생리적 치근흡수에 따른 치주인대에 신경섬유의 분포 및 변화는 유치의 성장발육에 따른 하나의 변화라고 생각된다.

• Journal of Periodontal and Implant Science
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• 제26권4호
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• pp.841-858
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• 1996

Epidermal growth factor(EGF) is one of polypeptide growth factors. EGF has been reported as a biological mediator which regulates activities of wound healing process including the cell proliferation, migration and metabolism. The purposes of this study is to evaluate the effects of EGF on the human periodontal ligament cells and human gingival fibroblast cells that promote regeneration of periodntal tissue. The mitogenic effects of epidermal growth factor on human periodontal ligament cells and human gingival fibroblasts were evaluated by determining the incorporation of 5-Bromo-2'-deoxy-uridine into DNA of the cells in a dose dependent manner. The prepared cells were the primary cultured gingival fibroblast and periodontal ligament cells from humans, the fourth or sixth subpassages were used in the experiments. Cells were seeded in DMEM containing 10% FBS. 1, 10, 50, 100, $200{\eta}g/ml$ and epidermal growth factor were added to the quiescent cells for 24 hours, 48 hours and 72 hours. They were labeled with $10\{mu}l/200{\mu}l$ 5-Bromo-2'-deoxy-uridine for the last 6 hours of each culture. The results of the five determinants were presented as mean and S.D.. The results were as follows : The DNA synthetic activity of human gingival fibroblasts were increased dose dependently by epidermal growth factor at 24 hours, 48 hours and 72 hours. The mitogenic effects were similar at the 24 and 48 hours of epidermal growth factor, but the DNA synthetic activity of human gingival fibroblasts generally decreased at 72 hours. The DNA synthetic activity of human periodontal ligament cells were increased dose dependently by epidermal growth factor at 24 hours but the DNA synthetic activity decreased at $200{\eta}g/ml$ of each hour. Generally the maximum mitogenic effects were observed at the 48 hours application of epidermal growth factor. The DNA synthetic activity of human periodontal ligament cells generally decreased lower at 24, 72 hours than at 48 hours the application of epidermal growth factor. In the comparison of DNA synthetic activity between human gingival fibroblasts and human periodontal ligament cells, human periodontal ligament cells had slightly higher proliferation activity than human gingival fibroblasts for a longer time at the high dosage of the epidermal growth factor. In conclusion, epidermal growth factor have important roles in the stimulation of DNA synthesis in human periodontal ligament cells and human gingival fibroblasts, and thus may be useful for clinical applications in periodontal regenerative procedures.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.539-556
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• 1995

Periodontal therapeutic modalities should be re-establishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, periodontal ligament cells must selective migrate to the deneded root surface, attached and proliferated it. Local pH concentration is one of the most factors that periodontal regeneration. The aims of this study were to examine on biological effects of pH to the human periodontal ligament cells in vitro, especially on the cell morphology, attachment, activity, vitality and viability. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Immediately after extraction, any soft tissue adhering to the cervical parts of the roots was carefully removed with a sterile curette. To produce different pH levels in the media, Eagle's MEM was adjusted from pH 6.6 to 8.2 in 0.2 intervals with 1 M NaOH and 1 N HCl. After cultivation, Then, Periodontal ligament cells were cultured at pH ranging from 6.6-8.2. attachment assay was done at 1, 2 day incubation and activity assay was done at 1, 2, 3 day incubation. The experiments were evaluated by scaning electron microscopic techniques (HITACHIX-650 Scaning Electron Microanalyzer, Tokyo, Japan), MTT assay, and the cultured periodontal ligament cells were fixed in neutral formalin for 24 hours and immunohistochemically processed by PCNA for proliferating ability. The surviving cells in the medium showed slightly increased volume and widening intercellular distances at low concentration of pH than control group (pH 7.4), and apparently shrinkage at high concentration of pH than control group (pH 7.4). The results of the statistical analysis from the experiment on attachment, vitality and viability were as follows. Attachment of periodontal ligament cells at 1st and 2nd day, similar attachment rate of low concentration pH compared with control value (pH 7.4). But above pH 8.0, attachment rate were statistically significant decrease from control value(P<0.05). Periodontal ligament cell's activities were maximum at pH 7.6 by MTT assay. Similar with control value at low concentration of pH. But, the activities were statistically significant decrease at high concentraration of pH(P<0.05). Cellular proliferating rate (PCNA index) were statistically significant decrease from control value at low and high concentration of pH(p<0.05). This results suggested that hjgh concentration pH, in other words, alkali pH was cytotoxic effects on human periodontal ligament cells in vitro.

• 대한관절경학회지
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• 제8권2호
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• pp.94-97
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• 2004

목적: 관절경하 후방 십자 인대 재건술시 지혈대의 필요성에 대한 언급된 문헌이 없어 지혈 대 없이 시행하는 본원의 관절경하 후방십자인대 재건술 결과 및 술기에 대해 보고하고자 한다. 대상 및 방법: 1998년 1월부터 2003년 5월까지 본원에서 후방십자인대 손상으로 관절경을 시행한 75례중 외측 측부인대 및 후외측 측부인대와 같은 동반손상으로 인해 관절외적 시술로 지혈대를 시행한 환자 16례와 술후 추시관찰이 12개월 이하인 10례를 제외한 49례의 단독 후방 십자 인대 손상 환자를 대상으로 하였고 자가 골-슬개건-골을 이용하여 재건한 경우 13례, 동종 골-슬개건-골을 이용하여 재건한 경우 19례, 동종 아킬레스 건을 이용하여 재건한 경우 17례였다 평가방법은 49례를 Lysholm knee scoring scale을 이용하여 비교하였다. 결과: 지혈대 없이 관절경하 후방 십자 인대 재건술을 한 경우 수술시간은 평균 105분 소요되었으며, 출혈로 인해 시야가 혼탁하여 지혈대를 사용한 경우는 없었다. 모든 환자에서 수술 부위의 부종, 국소 종창, 울혈, 환부 감염등은 관찰되지 않았다. Lysholm knee scoring scale을 이용한 평가 결과는 자가 골-슬개건-골을 이용한 경우는 평균 74점(fair) , 동종 아킬레스 건을 이용한 경우 75점(fair) , 동종 슬개건-골을 이용한 경우는 76점(fair)였다 결론: 관절경하 후방십자인대 재건술시 지혈대를 사용하지 않아도 수술에 어려움은 없으므로 지혈대 없이 재건술을 시행함으로써 지혈대로 인해 야기되는 합병증을 방지할 수 있을 것으로 생각된다.

• 대한족부족관절학회지
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• 제1권1호
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• pp.38-42
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• 1997

It was well known that arthrodesis of the tarsal joint is an exellent procedure to correct the flatfoot deformity for relieving pain. Recently, concept of the selective tarsal joint fusion instead of the triple fusion was developedto preserve the joint motion. To investigate and compare the effect of the each different tarsal fusion, we measured the strain at the spring ligament, medial roof of the medial longitudianl arch. Five fresh frozen cadevar foot specimens, with distal half of the tibia were utilized. The superomedial portion of the spring ligament complex was dissected from the origin to the insertion. For each specimen, a calibrated open liquid metal strain guage was secured along the length of the superomedial portion. Under the specially devised test rig, measurement of the strain was taken at each test condition from the tare weight 18.2 lb followed by 38.2 lb., 82.2 lb and a maximum loads of 134.6 lb. : 1) unfused condition, 2) isolated subtalar fusion 3) isolated talonavicular fusion 4) combined subtalar and talonavicular fusion 5) triple fusion. Statistics showed that siginificant reduction in strain following the triple fusion, and from the subtalar fusion to triple fusion.