• 한국운동역학회지
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• 제17권3호
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• pp.81-94
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• 2007

The purpose of this study was to critically review biomechanical studies on foot orthoses (FO) in normal and diseased foot and provide beneficial information obtained from researches until now and future researching focus. The search was performed by Medline and Embase database including studies published in English from January 1980 to April 2007. The searching terms were foot orthoses, foot orthotics, insoles and shoe insert. 57 studies including 54 journal articles and 3 abstracts were finally selected under the conditions of having clinical trials, FO, control condition, movement, scientific measuring system. The reviewed studies were divided into 10 categories according to subject characteristics; healthy normal, excessive pronation or flexible flat foot, rheumatoid arthritis, diabetes, medial knee osteoarthritis, forefoot varus, plantar fasciitis, patellofemoral syndrome, cavus foot and finite element model. In summary, first, soft and semirigid FOs with some degree of cushioning showed much higher comfort and efficacy than rigid FO. Second, no big differences between prefabricated and custom FO were shown. Third, the full length's FO was preferable to the half length's FO or simple arch supports. Fourth, the wearing of FO combining medial arch supports and metatarsal dome made positive roles to enhance comfort and functionality and redistribute plantar pressure under the foot. Fifth, for patients with knee-related diseases lateral wedges were preferable. Sixth, measuring systems were properly applied according to the types of foot diseases.

• Archives of Plastic Surgery
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• 제49권1호
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• pp.115-120
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• 2022

Background In addition to vascular endothelial cells, vascular smooth muscle cells (VSMCs) are subject to continuous shear stress because of blood circulation. The angiogenic properties of VSMCs in extracranial arteriovenous malformations (AVMs) may exceed those of normal blood vessels if the body responds more sensitively to mechanical stimuli. This study was performed to investigate the hypothesis that rapid angiogenesis may be achieved by mechanical shear stress. Methods VSMCs were obtained from six patients who had AVMs and six normal controls. The target genes were set to angiopoietin-2 (AGP2), aquaporin-1 (AQP1), and transforming growth factor-beta receptor 1 (TGFBR1). Reverse-transcriptase polymerase chain reaction (RT-PCR) and real-time PCR were implemented to identify the expression levels for target genes. Immunofluorescence was also conducted. Results Under the shear stress condition, mean relative quantity values of AGP2, AQP1, and TGFBR1 in AVM tissues were 1.927±0.528, 1.291±0.031, and 2.284±1.461 when compared with neutral conditions. The expression levels of all three genes in AVMs were higher than those in normal tissue except for AQP1 under shear stress conditions. Immunofluorescence also revealed increased staining of shear stress-induced genes in the normal tissue and in AVM tissue. Conclusions Shear stress made the VSMCs of AVMs more sensitive. Although the pathogenesis of AVMs remains unclear, our study showed that biomechanical stimulation imposed by shear stress may aggravate angiogenesis in AVMs.

• 구강회복응용과학지
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• 제21권2호
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• pp.153-167
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• 2005

The purpose of this study was to compare the v-shape thread with the square shape thread of fixture in the view of stress distribution pattern using finite element stress analysis. The finite element model was designed with the parallel placement of two standard fixtures(4.0 mm diameter ${\times}$ 11.5 mm length) on the region of mandibular 1st and 2nd molars. Three dimensional finite element model was created with the components of the implant and surrounding bone. This study simulated loads of 200 N at the central fossa in a axial direction (load A), 200 N at the buccal offset load that is 2 mm apart from central fossa in a axial direction (load B), 200 N at the buccal offset load that was 4 mm apart from central fossa in a axial direction (load C). These forces of load A',B',C' were applied to a $15^{\circ}$ inward oblique direction at that same site with 200 N. Von Mises stress values were recorded and compared in the supporting bone, fixture, and abutment screw. The following results have been made based on this study : 1. The highest stress concentration occurred at the cervical region of the implant fixture. 2. Von Mises stress value of off-site region was higher than that of central fossa region. 3. Square shape thread type showed more even stress distribution in the vertical and oblique force than V-shape thread type. 4. Stress distribution was the most effective in the case of buccal offset load (2, 4 mm distance from central fossa) in the square shape thread type. 5. V-shape thread type revealed higher von Mises stress value than square shape thread type in all environmental condition. The results from numerical analyses concluded that square shape thread type had the lower destructive stress and more stress distribution between the fixture and bone interface than V-shape thread type. Therefore, square shape thread type was regarded as optimal thread configuration in biomechanical concepts.

• Clinics in Shoulder and Elbow
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• 제12권2호
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• pp.207-214
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• 2009

목적: 관절경 하 회전근 개 봉합에서 일반적으로 건-봉합간 접촉면 (tenon-suture interface) 에 약한부위 (weak link)가 형성되어 있어 관절경 하 회전근 개 봉합은 개방적 봉합술보다 높은 재파열율을 가진다. 이 연구의 목적은 봉합사를 뼈에 고정할 때 관절경으로 사용할 수 있는 UU (Ulsan University) 봉합과 개방적 변형 MA (Mason-Allen) 봉합의 강도를 비교하는 것이다. 대상 및 방법: 한 구의 사체 극상근 건을 채취하여 절반으로 나눈 후 다시 절반을 나누어 사체의 어깨 관절 한 구당 네 개의 건을 만들어 총 24개의 검체를 만들었다. 두 봉합 형태 (UU, MA)는 무작위로 선택하였으며 각각의 건에 시행하였다. 검체는 0.25 Hz에서 5~30N의 조절된 외력하에서 50회 주기 부하 (cyclic loading)를 받았다. 각 검체는 초당 1mm의 전이가 되는 상황하에서 파열이 발생할 때(ultimate tensile load)까지 부하를 받았다. 조건 이완 (condition elongation), peak-to-peak 전이(displacement), 기울기 (stiffness), 최대 인장력 (ultimate tensile load), 파열 양상 (mode of failure) 등을 기록하였다. 결과: 주기 부하 실험에서 두 봉합 형태 간 유의 있는 차이는 없었다. 최대 장력 실험에서 UU 봉합과 변형 MA (Mason-Allen) 봉합 간에 통계학적으로 유의한 차이는 없었다 (109.4 N, and 110.6 N). 양 봉합 형태에서 가장 흔한 파열 양상은 봉합의 빠짐 (suture pull-out)이었다. 결론: UU 봉합과 변형 MA 봉합은 유사한 생역학적 특성을 가진다.

• 대한치과교정학회지
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• 제29권2호
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• pp.165-181
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• 1999

교정치료시 치아와 주위조직의 부작용을 최소로 하면서 최대의 치료결과를 얻기 위해서는 치료역학을 각 환자의 치아 및 주위 해부학적 환경에 맞도록 개인화 시켜야한다. 특히 성인 교정시 문제되기 쉬운 치근흡수 또는 치주질환으로 인한 치조골 손실로 인하여 치관/치근 비율이 변했을 때 치아의 저항중심위치의 변화와 관련된 생역학적 반응의 차이에 주의하여야 한다. 본 연구에서는 정상 치주조직뿐만 아니라 다양한 비정상적 치주 및 치아상태에서 치관/치근 비율이 변하였을 때 일정한 교정력하에서의 치아의 초기이동 양상을 연구하기 위하여, 성인의 인체 건조 두개골 및 하악골상에서 laser 반사측정법 및 lever and pulley force applicator와 photodetector를 이용하여, 상악 6전치군을 대상으로는 치조골높이를 각각의 치아에 대하여 2mm씩 총 8mm까지 감소시켰고, 하악 6전치군을 대상으로는 치근길이를 각각의 치아에 대하여 2mm씩 총6mm까지 감소시키면서, 이렇게 다양하게 정량화된 변수들 하에서 상하악6전치군의 저항중심의 위치변화를 연구한 결과 다음과 같은 결론을 얻었다. 1. 초기상태에서 상악 6전치군의 초기이동시의 저항중심점의 위치는 6전치 전체 평균치아 치근의 치경부(CEJ)로부터 치근첨 방향으로 약 $42.4\%$되는 위치에 있었으며, 각 치아의 치조골의 높이가 감소할수록 저항중심점은 치근첨방향으로 약 $76.7\%$되는 부위까지 이동하였다. 2. 상악 6전치군에서 저항중심점의 6전치 전체 평균 치조정으로부터의 거리는 치조골의 감소와 함께 지속적으로 감소하였으나, 치조골내의 평균 치근의 길이에 대한 비율은 치조골의 감소에 상관없이 약 $33\%$내외에서 비교적 일정하였다. 3. 초기상태에서 하악 6전치군의 초기이동시의 저항중심점의 위치는 6전치 전체 평균치아 치근의 CEJ로부터 치근첨방향으로 약 $43\%$되는 위치에 있었으며, 각 치아의 치근의 길이가 감소할수록 이 비율은 약 $54\%$까지 증가하였다. 그러나 CEJ로부터 저항중심점까지의 거리는 5.3mm전후로부터 3.3mm내외까지 감소하여 치근의 길이가 감소할수록 저항중심점이 CEJ방향으로 이동하였다. 4.치조골 또는 치근흡수시, 각각의 단위 흡수량에 따른 저항중심위치의 변화에 미치는 영향은 초기에는 치조골이 감소 될 때가 더 컸으나 전체 평균 치근길이의 중간부위에서의 영향은 비슷했다.

• 구강회복응용과학지
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• 제24권1호
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• pp.41-56
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• 2008

상용 임플란트의 표면을 개질하기 위해 물리적, 화학적 방법을 이용한 새로운 표면이 증가하고 있으며 이에 대한 골반응도 다를 것으로 예상할 수 있지만 대부분의 연구는 단순히 기계절삭형 임플란트와의 비교만을 하고 있다. 본 연구에서는 4종의 다른 개질된 표면을 가진 상용 임플란트를 가토의 경골에 식립한 후 생역학적, 조직형태학적으로 비교하였다. 연구 결과, 모든 임플란트는 6주 후 안정적인 골유착을 이루고 있었으며 4종의 표면개질의 차이에 의한 공진주파수 및 조직형태학적 골반응의 차이는 없었으며 표면개질을 비교하기 위해 피질골 하방으로 증식한 골을 비교하는 것이 유용하였다. 생역학적, 조직형태학적 골반응에 비해 미세단층촬영(micro-CT)를 이용하는 비교법은 유용성과 정확도가 낮은 것으로 나타났다.

• 한국운동역학회지
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• 제21권4호
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• pp.437-447
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• 2011

In this study, the lower limbs joints were analyzed for features based on the biomechanical characteristics of landing techniques according to height and landing on the ground type (flats and downhill). In order to achieve the objectives of the study, changes were analyzed in detail contents such as the height and form of the first landing on the ground at different angles of joints, torso and legs, torso and legs of the difference in the range of angular motion of the joint, the maximum angular difference between joints, the lower limbs joints difference between the maximum moment and the difference between COM changes. The subjects in this study do not last six months did not experience joint injuries 10 males in 20 aged were tested. Experimental tools to analyze were the recording and video equipment. Samsung's SCH-650A model camera was used six units, and the 2 GRF-based AMTI were used BP400800 model. 6-unit-camera synchronized with LED (photo cell) and Line Lock system were used. the output from the camera and the ground reaction force based on the data to synchronize A/D Syc. box was used. To calculate the coordinates of three-dimensional space, $1m{\times}3m{\times}2m$ (X, Y, Z axis) to the size of the control points attached to the framework of 36 markers were used, and 29 where the body was taken by attaching a marker to the surface. Two kinds of land condition, 40cm and 60cm in height, and ground conditions in the form of two kinds of flat and downhill slopes ($10^{\circ}$) of the landing operation was performed and each subject's 3 mean two-way RM ANOVA in SPSS 18.0 was used and this time, all the significant level was set at a=.05. Consequently, analyzing the landing technique as land form and land on the ground, the changes of external environmental factors, and the lower limbs joints' function in the evaluation were significantly different from the slopes. Landing of the slop plane were more load on the joints than landing of plane. Especially, knee extensor moment compared to the two kinds of landing, slopes plane were approximately two times higher than flat plane, and it was statistical significance. Most of all not so much range of motion and angular velocity of the shock to reduce stress was important. In the further research, front landing as well as various direction of motion of kinetic, kinetic factors and EMG variables on lower limbs joints of the study in terms of injury-prevention-approach is going to be needed.

• 대한치과교정학회지
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• 제31권2호통권85호
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• pp.237-248
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• 2001

치아이동에 대한 생력학적 반응은 골 형성과 재형성의 조합이라 할 수 있다. 골 형성과 흡수에는 국소적으로 작용하는 여러 부분비 인자가 관여한다. 대표적인 여성호르몬인 에스트로젠과 프로게스테론도 그 중의 한 인자로 성인 여성은 생리, 임신, 폐경 등 상태에 따라 체내 성호르몬 농도가 달라진다. 따라서 이러한 농도의 변화에 따라 골조직이 영향을 받을 수 있을 것으로 추정된다. 골모세포는 골흡수를 일으키는 호르몬인 PTH, Vit $D_3$ 등에 일차적으로 반응함으로써 골형성 뿐만 아니라 골흡수에도 일정한 역할을 하고 있어 파골 세포에 영향을 주는 부분비 인자도 추측해 볼 수있다. 본 연구에서는 ROS17/2.8 및 HOS 세포주를 배양하면서 에스트로젠 및 프로게스테론 등 여성 호르몬을 처리한후 골모세포의 증식과 활성에 미치는 영향을 측정하여 다음과 같은 결과를 얻었다. 1. 에스트로젠은 HOS 세포의 증식을 억제하였으며 ROS17/2.8 세포의 증식은 촉진하는 것으로 관찰되었다. 2. 에스트로젠은 HOS 세포의 alkaline phosphatase 활성을 증가시켰고 ROS 세포에서는 효소활성을 억제하는 것으로 나타났다. 3. 프로게스테론은 HOS 및 ROS17/2.8 세포 모두의 증식을 억제하였으며 골모세포의 alkaline phosphatase 활성에는영향을 미치지 못하였다. 4. 에스트로젠과 프로게스테론은 골모세포내에서 생성되는 superoxide, nitric oxide 및 gelatinase 활성 등 골모세포의 기능에는 유의한 변화를 일으키지 않았다.

• 대한치과보철학회지
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• 제36권3호
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• pp.468-482
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• 1998

Since the concept of osseointegration was introduced by Branemark of Sweden, dental implants have been used for various dental prosthetic treatments. The survival rate of dental implant is likely to be closely related to the total biomechanical role of each component of implant system. The use of interchangeable component is very attractive for dental practitioners because such an approach would save treatment cost, flexibility of prosthetic treatment options as well as conveniences. Therefore, the use of interchangeable implant system has been increasing without scientific assessment of safety and efficacy of various interchangeable implant system. The purpose of this study, therefore, were to compare the geometric characteristic of four interchangeable dental implant screws and the loosening torque of these screws. Four types of dental implant screws tested in this study were Nobelpharma, 3i, Impla-med, Restore. Four screws each of the test specimens were subjected for scanning electron microscopic examinations under the same condition and a 35x magnified standard SEM picture was objected from each test specimen using JSM-5200 scanning microscope. From each of the SEM pictures, eight parameters. i.e., diameter of screw head. screw length, thread pitch, major diameter. neck diameter, neck length, crest width and root width were determined using a caliper. The measurement for each parameters were then corrected for their magnification factor. The loosening torque were also determined by using a torque gauge. All of the measurements were statistically analyzed by ANOVA test and multiple range test. Statistical significance was set in advance at the probability level of less than 0.05. All analyses were done with SPSS software for the personal computer. The conclusion obtained from this studies were summarized as the following; 1. No statistically significances were noted in the thread pitch. and crest width in the four screws, and in the case of major diameter, the Impla-med screw was significantly smaller than the other three screws (p<0.05). Therefore, four implant bolts could be physically inserted in a abutment nuts. 2. The diameter of screw head was decreased in the order of Restore, 3i, Nobelpharma, Impla-med screws and the length of screws were decreased in the order of 3i, Restore, Nobelpharma and Impla-med. The diameter of neck was decreased in the order of Impla-med, Restore. Nobelpharma, 3i screws. The differences of each of these parameters were statistically significant (p<0.05). The width of root of screws were decreased in the order of Nobelpharma, Impla-med, Restore and 3i. The differences among Nobelpharma and Impla-med. Restore and 3i were statistically significant (p<0.05). 3. When the screws were loosening 1, 3, 4 and 5 times, the loosening torque for Impla-med and 3i screws were significantly higher than that of Nobelpharma or Restore screws (p<0.05). However, when statistically smaller than that of 3i, Restore or Nobelpharma screws(p<0.05).

• 구강회복응용과학지
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• 제17권4호
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• pp.245-256
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• 2001

The purpose of this study is to analyze the mechanical stress and displacement on the jaws during the simulated bilateral clenching task on the three-dimensional finite element model of the dentated skull with unilateral molar loss. For this study, the computed tomography(G.E.8800 Quick, USA) was used to scan the total length of human skull in the frontal plane at 2.0mm intervals. The fully assembled finite element model consists of the articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. The FE model was used to simulate the bilateral clenching in intercuspal position. The loading condition was the force of the masseter muscle exerted on the mandible as reported by Korioth et al. degrees of freedom of the zygomatic region where the masseter muscle is attached were fixed as restraints. In order to reflect the actual action of the muscles force, the displacement of the region was attached where the muscle is connected to the temporal bone and restraint conditions were given values identical to values at the attachment region of the masticatory muscle but with the opposite direction of the reaction from when the muscle force is acted on the mandible. Although the mandible generally has higher displacement and von Mises stress than the maxilla, its mandibular corpus on the molar-loss side has a higher stress and displacement than the molar-presence side. Because the displacement and von Mises Stress was the highest on the lateral surface of mandibular corpus with molar loss, the stress level of the condyle on the molar-loss side is greater than that of the molar-presence side, which in turn caused the symphysis of the mandible to bend. In conclusion, the unilateral posterior bite collapse with molar loss under para-functional activities such as bruxism and clenching can affect the stress concentration on the condyle and mandibular corpus. It is therefore necessary to consider the biomechanical function of dento-skeleton under masticatory force while designing the occlusal scheme of restoration on alveolar bone with the posterior collapse.