• Journal of Oral Medicine and Pain
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• v.42 no.2
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• pp.44-48
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• 2017

Chronic temporomandibular joint dislocation is defined as an acute dislocation that cannot be reduced or that recurs for more than one month. The management of dislocation depends on patient status and the duration of dislocation and ranges from conservative reduction to a surgical approach. In the present cases, a 64-year-old male was referred to our department for treatment of chronic dislocation for 6 weeks. The dislocation might be occurred by endotracheal intubation. A 70-year-old female was referred to our department with repeat right condyle dislocation after reduction of dislocation at a local clinic. When she visited for later treatment of new dentures, her condyle had been dislocated again for several weeks. In both cases, we tried to treat the dislocation with several manipulations, which were unsuccessful. Finally, chronic dislocation was successfully treated by surgical traction under general anesthesia without relapse. Surgical traction is a simple, effective option with the lowest morbidity of surgical procedures for chronic dislocation when conservative reduction is unsuccessful.

• Journal of Oral Medicine and Pain
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• v.47 no.1
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• pp.27-37
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• 2022

Purpose: This study aimed to broaden our understanding of the predisposing factor and treatment of dislocation by analyzing and evaluating the morphology of the articular eminence (AE) in subjects with temporomandibular joint (TMJ) dislocation using cone beam computed tomography (CBCT). Methods: The subjects were divided into two groups: dislocation (31 subjects) and control (32 subjects). CBCT was used to examine 126 TMJs in 63 subjects (26 males, 37 females). The height, width, and posterior slope of the AE were measured in the parasagittal plane. The posterior slope was measured using the "top-roof line angle (TR angle)" method and the "best-fit line angle (BF angle)" method. The AE on the left side (AEL) and the AE on the right side (AER) of the subjects in the dislocation group were separately analyzed and compared with the control group after taking measurements. The average value of both sides was used when comparing with subjects with bilateral dislocation. Results: Dislocations were more frequent in females (67.7%) than in males (32.3%). The dislocation group showed a gentler TR angle than the control group in the AER and in the average of AE on the both sides (AEB). The same group also showed a wider AE in the AEL and the AER (p<0.05). In subjects with unilateral dislocation, the width of the AE with dislocation was narrower and the TR angle and BF angle was steeper than the other side without dislocation (p<0.05). Conclusions: In subjects with unilateral TMJ dislocation, the posterior slope of the AE is steeper, and the width is narrower at the site of dislocation compared to the site without dislocation. However, in subjects with bilateral TMJ dislocation, AEB were wider, and the mean value of the posterior slope of AEB was gentler than that of the control group.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.2
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• pp.168-172
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• 1999

The 9 $\mu\textrm{m}$ GaN films on sapphire substrate were grown by Hydride vapor phase epitaxy. Dislocation density of these GaN films was measured by TEM. GaN film with crack free and mirror surface was directly grown on sapphire substrate. The dislocation density of this GaN film was $2{\times}10^9/cm^2$. The surface of GaN film on patterned GaN layer also presented a smooth mirror. But a part of GaN surface included holes because of incomplete coalescence. The dislocation density of GaN film above the mask region was lower than that in the window region. Especially, the dislocation density in the region between mask center and window region was close to dislocation free. The average dislocation density of ELO GaN was $8{\times}10^7/cm^2$.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.6
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• pp.477-482
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• 2008

The influence of dislocation substructure of metallic materials on ultrasonic velocity has been experimentally investigated. The test materials of pure Cu, brass (Cu-35Zn), 2.25Cr-1Mo steel, and AISI 316 with different stacking fault energy (SFE) are plastically deformed in order to generate dislocation substructures. The longitudinal wave velocit $(C_L)$ decreases as a function of tensile strain in each material. The $C_L$ of Cu-35Zn and AISI 316 decreases monotonously with tensile strain, but $C_L$ of Cu and 2.25Cr-1Mo steel shows plateau phenomena due to the stable dislocation substructure. The variation of ultrasonic velocity with the extent of dislocation damping and dislocation substructures is discussed.

• Journal of the Korean Arthroscopy Society
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• v.1 no.1
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• pp.98-101
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• 1997

Acute patellar dislocation is a painful, terrifying experience that always occurs suddenly. The recurrence is unfortunately common and each experience is just as painful to the patient. With each acute dislocation, additional intraarticular derangement occurs. Therefore the goals of treatments are not only to relieve acute pain by prompt reduction of the dislocation but also to remove any chondral or osteochondral fragments that may be present within the knee joint and to restore normal patellofemoral anatomy, thereby preventing recurrent dislocation and avoiding future patellar subluxation. To present the details of arthroscopic medial retinacular repair in acute patellar dislocation. we report 2 patients with treatment of acute patellar dislocation with osteochondral loose body.

• Journal of Korean Foot and Ankle Society
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• v.4 no.1
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• pp.39-43
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• 2000

A subtalar dislocation of the foot is a dislocation of the talonavicular and talocalcaneal joint while the tibiotalar relationship is unchanged. Posterior subtalar dislocation in particular, is a extremely rare. Only a few cases were reported previously in the literature. We treated a 25 year-old man who sustained the posterior subtalar dislocation in high energy traffic accident. The dislocation of subtalar joint was reduced by closed means with excellent clinical result. In this paper, we report 1 case of posterior dislocation of the subtalar joint and describe the pathomechanics, diagnosis, and treatment.

• Interaction and multiscale mechanics
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• v.6 no.2
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• pp.127-136
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• 2013

In this study, atomistic simulations are performed to study the effect of Al solute on the behaviour of edge dislocation in Mg alloys. After the dissociation of an Mg basal edge dislocation into two Shockley partials using molecular mechanics, the interaction between the dislocation and Al solute at different temperatures is studied using molecular dynamics. It appears from the simulations that the critical shear stress increases with the Al solute concentration. Comparing with the solute effect at T = 0 K, however, the critical shear stress at a finite temperature is lower since the kinetic energy of the atoms can help the dislocation conquer the energy barriers created by the Al atoms. The velocity of the edge dislocation decreases as the Al concentration increases when the external shear stress is relatively small regardless of temperature. The Al concentration effect on the dislocation velocity is not significant at very high shear stress level when the solute concentration is below 4.0 at%. Drag coefficient B increases with the Al concentration when the stress to temperature ratio is below 0.3 MPa/K, although the effect is more significant at low temperatures.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2304-2311
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• 2021

The dislocation density in strain-hardened Alloy 690 was analyzed using scanning transmission electron microscopy (STEM) to study the relationship between the local plastic strain and susceptibility to primary water stress corrosion cracking (PWSCC) in nuclear power plants. The test material was cold-rolled at various thickness reduction ratios from 10% to 40% to simulate the strain-hardening condition of plant components. The dislocation densities were measured at grain boundaries (GB) and in grain interiors of strain-hardened specimens from STEM images. The dislocation density in the grain interior monotonically increased as the strain-hardening proceeded, while the dislocation density at the GB increased with strain-hardening up to 20% but slightly decreases upon further deformation to 40%. The decreased dislocation density at the GB was attributed to the formation of deformation twins. After the PWSCC growth test of strain-hardened Alloy 690, the fraction of intergranular (IG) fracture was obtained from fractography. In contrast to the change in the dislocation density with strain-hardening, the fraction of IG fracture increased remarkably when strain-hardened over 20%. From the results, it was suggested that the PWSCC growth behavior of strain-hardened Alloy 690 not only depends on the dislocation density, but also on the microstructural defects at the GB.

• Journal of Korean Foot and Ankle Society
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• v.17 no.3
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• pp.182-188
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• 2013

Purpose: We evaluate clinical manifestations and radiologic features of ankle fracture & dislocation, as well as the usefulness of computed tomography on posterior ankle fracture & dislocation to study factors contributing to ankle fracture & dislocation. Material and Methods: Ankle dislocation was defined as the center of talar body being translated over the cortex of tibia on AP or lateral view on simple X-ray. Surgical treatments of 30 patients from January 2007 to March 2012 were categorized according to the injury mechanism, the direction of dislocation and fracture site. Joint involvement of posterior malleoalr fracture was evaluated through simple x-ray and computed tomography. We treated surgically if posterior malleolus fracture involves more than 25% of dital tibial articular surface. Thereafter, clinical outcomes were identified through radiographs and by using the AOFAS score. Results: The mean age was 42(13-78) years old, and slip down was the most common injury mechanism (13 cases). Car accident (6 cases) and fall accident (4 cases) were the next frequently found injury mechanisms. As for the types of ankle fracture, posterior fracture and dislocation (21 cases, 43.3%) was most commonly found. Out of these 21 cases, 15 cases involved trimalleolar fracture, and 19 cases were associated with posterior malleolar fracture. Danis-weber type B and C patients were 11 cases and 10 cases respectively. Articular involvement of posterior malleolar fracture turned out to be average 27.9%(5.1%~49.1%) on simple x-ray. The rate was evaluated as average 31.7%(12.6%~55.3%) on computed tomography which was conducted 15 times, and led us to more meaningful data. Conclusion: Anterolateral fracture and dislocation often accompanied open dislocation. Posterior fracture dislocation was most commonly found. Posterior malleolus was an important factor that ensures posterior stability of the ankle joint. Computed tomograph is useful to evaluate the articular involvement of posterior malleolar fracture.

• Journal of Korean Foot and Ankle Society
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• v.17 no.1
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• pp.28-33
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• 2013

Purpose: In previous study, the frequency of osteoarthritis and discomfort were high in ankle fracture-dislocation but detail results about ankle fracture-dislocation has rarely been investigated. In this study, we retrospectively analyze the outcome of the operative treatment of ankle fracture with dislocation for over-2 years follow up. Materials and Methods: There were 47 cases of ankle fracture-dislocation in our hospital from March 2007 to May 2010. We investigated 20 patients who underwent operation and were possible for over-2 years follow up. The result was estimated with the direction of dislocation, fracture type, the time of bone union and post-traumatic osteoarthritis with plain radiologic images. In clinical assessment, we statistically evaluated the function and pain through AOFAS score and Olerud & Molander scoring system. Results: By Lauge-Hansen classification, there were 13 cases(65%) of pronation-external rotation and 6 cases(30%) of supination-external rotation, 1 case(5%) of supination-adduction. AOFAS score was 85.5, and Olerud & Molander score was "excellent" in 8 cases, "good" in 5 cases, "fair" in 3 cases and "poor" in 4 cases. Postoperative complications in 4 cases revealed post-traumatic arthritis. All kinds of lateral dislocation of ankle fracture was 15 cases and the most common. Of these, all 3 cases, anterolateral dislocation showed post-traumatic osteoarthritis. Conclusion: In ankle fracture-dislocation, post-traumatic osteoarthritis occurred in 4 of 20 patient(20%). Especially, the possibility of post-traumatic osteoarthritis was more in cases of anterolateral or lateral dislocation. So, it must be needed that deliberate examination, for example, preoperative MRI and sufficient explanation to patient. Also, we have to follow up the patients carefully.