• 대한치과보철학회지
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• 제21권1호
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• pp.59-66
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• 1983

Distal extension partial dentures are supported by both the relatively rigid teeth and the resilient mucosa. So impression techniques of residual alveolar ridge in case of distal extension partial denture have particular importance in order to broad distribution of the masticatory force. McLean recognized the need for recording the tissues supporting distal extension partial denture base in functional form to equalize the resilient and non-resilient support, and this was called functional impression. Many investigators proposed various techniques of the functional impression for a distal extension partial denture, but only a little studies were performed about displacement of soft tissue under distal extension partial denture base. The purpose of this study is to investigate the amount of vertical displacement of the soft tissue under distal extension partial denture base by different functional impression techniques. Impression techniques used were Z.O.P. Impression, Selective Tissue Placement Impression, Functional Relining Impression. Measurement of the vertical displacement of soft tissue were made with Depth Gauge and Measuring Platform. A Anatomic Impression was used as a control. The results were tested statistically using 3 way ANOVA and Scheffe test. The followings were the results obtained from this study. 1. The greatest amount of soft tissue displacement was observed in the center of the retromolar pad. 2. No significant differences were found between the crest of alveolar ridge and the buccal shelf area. 3. The greatest soft tissue displacement was observed in Functional Relining Impression using Iowa wax, and the least displacement was observed in Selective Tissue Placement Impression using murcaptan rubber base. 4. No significant differences were found between finger pressure and biting pressure in Z.O.P. Impression, but greater displacement was observed by biting pressure than finger pressure in Functional Reling Impression.

• Imaging Science in Dentistry
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• 제33권2호
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• pp.63-70
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• 2003

Purpose: To describe the MRI findings of the retrodiskal tissue in patients presenting with TMJ internal derangement and to correlate these findings with clinical and other MRI manifestations. Materials and Methods: One hundred eighteen joints of 63 patients with TMJ internal derangement were examined by MRI. Tl-weighted sagittal MR images taken in both closed- and open-mouth were evaluated for the presence of demarcation between disk and retrodiskal tissue, the presence of low signal intensity, and the depiction of the temporal part of the posterior attachment. The results were correlated with the duration of TMJ internal derangement, the presence of pain, and other MRI findings, including the type of internal derangement, the extent of disk displacement, the degree of disc deformation, and the presence of osteoarthrosis. Results: A significant relationship between the presence of low signal intensity in the retrodiskal tissue and other MRI findings was determined. Low signal intensity on the open-mouth view was observed more frequently in patients with disc displacement without reduction, severe disc displacement and deformation, and osteoarthrosis (p<0.05). The demarcation between disk and retrodiskal tissue, and the depiction of the temporal part of the posterior attachment(TPA) were correlated neither with clinical, nor with other MRI findings. Conclusion: This study suggests that low signal intensity in the retrodiskal tissue on open-mouth MR image can be indicative of advanced stages of disk displacement.

• Archives of Plastic Surgery
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• 제43권5호
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• pp.430-437
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• 2016

Background Accurate breast volume assessment is a prerequisite to preoperative planning, as well as intraoperative decision making in breast reconstruction surgery. The use of three-dimensional surface imaging (3D scanning) to assess breast volume has many advantages. However, before employing 3D scanning in the field, the tool's validity should be demonstrated. The purpose of this study was to confirm the validity of 3D-scanning technology for evaluating breast volume. Methods We reviewed the charts of 25 patients who underwent breast reconstruction surgery immediately after total mastectomy. Breast volumes using the Axis Three 3D scanner, water-displacement technique, and magnetic resonance imaging (MRI) were obtained bilaterally in the preoperative period. During the operation, the tissue removed during total mastectomy was weighed and the specimen volume was calculated from the weight. Then, we compared the volume obtained from 3D scanning with those obtained using the water-displacement technique, MRI, and the calculated volume of the tissue removed. Results The intraclass correlation coefficient (ICC) of breast volumes obtained from 3D scanning, as compared to the volumes obtained using the water-displacement technique and specimen weight, demonstrated excellent reliability. The ICC of breast volumes obtained using 3D scanning, as compared to those obtained by MRI, demonstrated substantial reliability. Passing-Bablok regression showed agreement between 3D scanning and the water-displacement technique, and showed a linear association of 3D scanning with MRI and specimen volume, respectively. Conclusions When compared with the classical water-displacement technique and MRI-based volumetry, 3D scanning showed significant reliability and a linear association with the other two methods.

• Advances in biomechanics and applications
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• 제1권2호
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• pp.95-109
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• 2014

Peri-acetabular bone ingrowth plays a crucial role in long-term stability of press-fit acetabular cups. A poor bone ingrowth often results in increased cup migration, leading to aseptic loosening of the implant. The rate of peri-prosthetic bone formation is also affected by the polar gap that may be introduced during implantation. Applying a mechano-regulatory tissue differentiation algorithm on a two-dimensional plane strain microscale model, representing implant-bone interface, the objectives of the study are to gain an insight into the process of peri-prosthetic tissue differentiation and to investigate its relationship with implant-bone relative displacement and size of the polar gap. Implant-bone relative displacement was found to have a considerable influence on bone healing and peri-acetabular bone ingrowth. An increase in implant-bone relative displacement from $20{\mu}m$ to $100{\mu}m$ resulted in an increase in fibrous tissue formation from 22% to 60% and reduction in bone formation from 70% to 38% within the polar gap. The increase in fibrous tissue formation and subsequent decrease in bone formation leads to weakening of the implant-bone interface strength. In comparison, the effect of polar gap on bone healing and peri-acetabular bone ingrowth was less pronounced. Polar gap up to 5 mm was found to be progressively filled with bone under favourable implant-bone relative displacements of $20{\mu}m$ along tangential and $20{\mu}m$ along normal directions. However, the average Young's modulus of the newly formed tissue layer reduced from 2200 MPa to 1200 MPa with an increase in polar gap from 0.5 mm to 5 mm, suggesting the formation of a low strength tissue for increased polar gap. Based on this study, it may be concluded that a polar gap less than 0.5 mm seems favourable for an increase in strength of the implant-bone interface.

• 비파괴검사학회지
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• 제32권5호
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• pp.469-483
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• 2012

인체 연조직에서 기계적인 진동의 전달 특성은 조직의 탄성 특성에 의존한다. 연조직의 진동 특성으로부터 암이나 종양을 진단할 수 있기 때문에 진동의 전달 특성에 대한 연구는 중요한 의미를 가진다. 이 논문은 연조직의 표면에 위치하는 여러 형태의 응력 진동원에 의해 연조직 내에 발생되는 변위 패턴을 분석하고 비교하였다. 진동원으로는 수직하중, 접선하중, 그리고 면외전단하중이 고려되었다. 점탄성 단일층에서의 변위에 대한 이론적 표현식을 구하였고, 수치계산은 반공간 및 무한평판조직에서 수행되었다. 그리고 유한크기조직에서의 변위패턴을 유한요소법으로 시뮬레이션하였다. 응력 형태, 진동원 크기 및 주파수, 그리고 경계면이 변위에 미치는 영향이 분석되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권5호
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• pp.457-462
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• 2005

The aim of this study is to evaluate the relative signal intensity of TMJ retrodiscal tissue in T2-weighted MRI as diagnostic marker of temporomandibular disorder(TMD). 58 temporomandibular joints from 29 TMD patients (14 men & 15 women) were evaluated. The relative signal intensity of retrodiscal tissue in T2-weighted MRI was referenced to brain gray matter same size of the region of interest(ROI). The collected data was compared to disc positions (normal, anterior disc displacement with reduction, anterior disc displacement without reduction), the presence of joint effusion. The relative signal intensity of retrodiscal tissue was significantly increased when the disc was displaced without reduction. And the relative signal intensity of retrodiscal tissue was significantly increased when joint effusion was present. The results suggest that evaluating the relative signal intensity of TMJ retrodiscal tissue using a T2-weighted MRI is valuable as a non-invasive tool for diagnosing the procession of TMD.

• 산업경영시스템학회지
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• 제35권4호
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• pp.24-32
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• 2012

Of many approaches to reduce motion analysis errors, the compensation method of anatomical landmarks estimates the position of anatomical landmarks during motion. The method models the position of anatomical landmarks with joint angle or skin marker displacement using the data of the so-called dynamic calibration in which anatomical landmark positions are calibrated in ad hoc motions. Then the anatomical landmark positions are calibrated in target motions using the model. This study applies the compensation methods with joint angle and skin marker displacement to three lower extremity motions (walking, sit-to-stand/stand-to-sit, and step up/down) in ten healthy males and compares their performance. To compare the performance of the methods, two sets of kinematic variables were calculated using different two marker clusters, and the difference was obtained. Results showed that the compensation method with skin marker displacement had less differences by 30~60% compared to without compensation. And, it had significantly less difference in some kinematic variables (7 of 18) by 25~40% compared to the compensation method with joint angle. This study supports that compensation with skin marker displacement reduced the motion analysis STA errors more reliably than with joint angle in lower extremity motion analysis.

• Journal of Oral Medicine and Pain
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• 제36권3호
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• pp.177-185
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• 2011

이 연구의 목적은 측두하악관절에서 통증의 존재에 따른 T1,T2 강조 영상에서 원판후조직의 상대적 신호 강도의 연관성을 평가하는 것이다. 본 연구는 양측성 관절원판전위가 있으면서 편측성으로 관절통증을 가진 61명의 환자의 122개의 관절을 근거하여 행해졌다. 자기공명영상의 평가는 원판후조직의 신호강도의 측정과 관절원판의 위치, 삼출액, 퇴행성 변화와 같은 관절상태를 포함하였다. 원판후조직의 상대적 신호강도는 대뇌의 회질의 신호강도를 기준으로 구해졌다. 원판후조직의 상대적 신호강도와 관절통증, 개구량, 관절원판위치, 삼출액, 퇴행성 변화간의 상관성이 조사되었다. 그 결과, T1 강조 영상에서 상대적 신호강도가 비통증관절에 비해 통증관절에서 유의성있게 높게 나타났다. 또한 관절원판 전위의심도와 통증 간에 유의성 있는 상관성이 있는 것으로 나타났다. 이러한 결과는 관절원판전위 환자에서 발생하는 악관절 통증이 원판후조직의 손상과 밀접한 관련성이 있음을 시사하는 것으로서 따라서 악관절의 T1 강조영상에서 관찰되는 원판후조직의 상대적 신호강도의 크기는 악관절 통증의 존재를 나타내는 진단학적 표시자로 사용될 수 있을 것으로 생각된다.

• 대한치과교정학회지
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• 제10권1호
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• pp.29-36
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• 1980

Inclined plane, one of frequently used orthodontic appliances, may cause posterior displacement of mandible and injure the normal growth of temporomandibular joint. So author carried out the mandibular posterior displacement experimentally induced by inserting inclined plane in the rat incisors in order to investigate the histological reactions occuring in the temporomandibular joint of experimental animals. Following results were obtained. 1. The posterior displacement of condyle resulted in the widening of anterior synovial space with anterior condylar hyperplasia and posterior condylar atrophy. In addition, tissue changes were more severe in young rats than in adult rats. 2. The tissue reactions were localized only to condylar head ana there were no evidence of traumatic features in young rats. In adult rats, hemorrhage was an additional finding 1 week after experiment. 3. The remodelling processes were accompanied by the increasing or reduction of fibrous layer and subsequent replacement by cartilage layer occured massively and abruptly in young rats, it occured slightly and slowly in adult rats. 4. The remodelling process of injured condyle occured from 1 week to 4 weeks after experiment and completed between 8 weeks after experiment.

• Archives of Plastic Surgery
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• 제47권4호
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• pp.360-364
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• 2020

In this report, we present a rare case of solid silicone implant displacement to the contralateral side after aesthetic gluteal augmentation, a phenomenon that has never been reported before in the literature. A 29-year-old woman with a history of gluteal augmentation 9 months previously and soft tissue infection presented for a consultation due to 3 days of sudden progressive pain in the right gluteus with erythema and edema, without a history of trauma. Displacement of the left gluteal implant to the right gluteal pocket was shown by magnetic resonance imaging. Because the patient refused implant removal, the decision was made to perform capsulotomy, to reconstruct the gluteal pockets, and to preserve the implants. The patient showed a satisfactory early and late postoperative course. Possible causes of this complication include poor surgical technique, with insufficient tissue preservation to keep the pockets apart, and the presence of seroma or hematoma that favored an infectious process, thereby leading to deterioration of the dissected soft tissues with dehiscence of the wound favoring the displacement of the implant.