• Imaging Science in Dentistry
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• v.33 no.2
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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.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.93-106
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• 2001

T-joint and hopper knuckle joint models are typical welded joints in ship structure, which are very susceptible to fatigue damage under service condition. Fatigue test and fracture mechanical analysis were performed on these joints to find out characteristics of fatigue behavior. Unified S-N curve was developed from the test results of these two types of joint using hot spot stress concept, and also propagation life was also estimated using Paris' crack propagation law. Residual stress effect on propagation life was considered in calculating propagation life, as was done with thermo-elasto-plastic FE analysis and residual stress intensity factor calculation. Fatigue life of similar kinds of welded joint could be predicted with this unified S-N curve and fracture mechanical analysis technique.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.1
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• pp.50-58
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• 2022

Objectives: Osteoarthritis (OA) is the most prevalent and disabling joint disease in the world. Temporomandibular joint (TMJ) exercise is a widely used treatment and could be a beneficial and long-term tool for treating TMJ OA. The present study aims to evaluate the effects of therapeutic exercise in the conservative treatment of TMJ OA. Materials and Methods: A single-group experimental pre-post test was performed. We included patients who met the diagnostic criteria for TMJ OA. Outcome variables were pain intensity (visual analogue scale), functionality (Helkimo index), and structural changes (ultrasound). Follow-up periods were at months 1, 3, and 6. The intervention included a home-based program with thermotherapy, manual therapy, and therapeutic exercise during the entire follow-up period. Results: We included 15 patients and 26 joints, all women with a median age of 57 years (range, 49-62 years). Median change in pain intensity on joint palpation, mouth opening, and at rest at the first month was 47.5 mm, 51 mm, and 60 mm, respectively, and 48 mm, 49.5 mm, and 42.5 mm, at six months (P=0.001). The Helkimo index showed significant improvement in medians from baseline severe dysfunction (17 points) to minimal dysfunction at three and six months (2 points) (P=0.001). Ultrasound showed improved disc position. Conclusion: This study demonstrated significant improvements in pain, function, and joint disc position and represents a valuable tool for the long-term treatment of patients with TMJ OA.

• Journal of Korean Physical Therapy Science
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• v.22 no.1
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• pp.29-36
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• 2015

Purpose : The purpose of present study was to improve communication of pain expressing terms and pain intensity between patient and physical therapist, and initiated to objectify a measurement of subjective pain. Methods : Data were delivered to 249 people by a self-completion questionnaire, and analyzed 160 copies except for 87 mark error of the collected 247 questionnaires. The questionnaire included a question on 55 terms used to describe pain, the type of the pain, and pain intensity using VAS (visual analogue scale). Results : The results were as follows; 'Tight' was the most frequently being expressed term of muscular pain, subsequently to 'knot' and 'dull'. 'Tear' was the term representing the most strong pain of muscular pain, subsequently to 'rupture' and 'squeeze'. 'Stinging' was the most frequently being expressed term of neurologic pain, subsequently to 'get shocked' and 'wriggle'. 'Burn' was the term representing the most strong pain of neurologic pain, subsequently to 'sear' and 'get shocked'. 'Creak' was the most frequently being expressed term of joint pain, subsequently to 'peel' and 'out of joint'. 'Break' was the term representing the most strong pain of joint pain, subsequently to 'peel' and 'crack'. Conclusion : The objectification of pain terms will be used to help physical therapist to check the patient's pain.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.63-71
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• 2000

The authors assessed if there is a relationship between joint effusion and the presence of pain, and between joint effusion and disc displacement in 446 temporomandibular joints of 223 subjects who visited the Department of Oral Medicine, Kyungpook National University Hospital with the complaints of temporomandibular joint problem. The amount of joint effusion and the position of disc were determined from magnetic resonance images of the temporomandibular joints. The position of disc was classified into normal disc position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWOR). The amount of joint effusion was graded according to the extent of joint area of high signal intensity on T2-weighted MR images. These findings were correlated with one another and statistically analyzed. The results were as follows; 1. The incidence of temporomandibular joint pain Was higher in the joints with higher amount of joint effusion (P<0.001). 2. The proportion of temporomandibular joints with higher amount of effusion increased in the joints with more advanced articular disc displacement (P<0.001).

• Journal of Mechanical Science and Technology
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• v.16 no.2
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• pp.182-191
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• 2002

The reliable stress intensity factor analysis is required for fracture mechanics design or safety evaluation of mechanical joints at which cracks often initiate and grow. It has been reported that cracks in mechanical joints usually nucleate as corner cracks at the faying surface of joints and grow as elliptical arc through cracks. In this paper, three dimensional finite element analyses are performed for elliptical arc through cracks in mechanical joints. Thereafter stress intensity factors along elliptical crack front including two surface points are determined by the virtual crack closure technique. Virtual crack closure technique is a method to calculate stress intensity factor using the finite element analysis and can be applied to non-orthogonal mesh. As a result, the effects of clearance on the stress intensity factor are investigated and crack shape are then predicted.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.921-927
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• 1996

The purpose of this study is to compute the stress intensity factors of various conditions in the cracked p! ate. The stress intensity factor of pin-loaded cracked plate is investigated using the finite element method. This paper is divided into the two parts. The first part is the contact analysis, and the second is to compute the stress intensity factors. In the contact analysis, the iterative method is used, and convergence of this method is presented. In the computation of the stress intensity factors of plate, the length of crack, clearance, and angle are considered

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.728-731
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• 2005

The objective of this paper is to perform measurements of vibration intensity of a coupled beam. The propagation of flexural waves generates the out of plane vibration of the coupled beam. The longitudinal waves are generated due to the mode conversion at the structural joint of the coupled beam. The propagation of longitudinal waves generates the in plane vibration of the coupled beam. In order to identify the direction of vibrational power on the coupled beam, the in plane vibration intensity as well as the out of plane vibration intensity needs to be measured. The cross spectral method has been implemented to measure the in-plane vibration intensity as well as out of plane vibration intensity. The results shelved that the experimental method can be effectively used to measure the in-plane vibration intensity as well as the out of plane vibration intensity of coupled beams.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.989-1002
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• 2018

Grouting for the rock joint is to strengthen the rock strata by infiltrating cement grout materials into the rock joints. Grouting is one of a field of study which is difficult to develop deterministic and quantitative design approach because of multiphase behaviors of grout materials and 3 dimensional features of rock joints. Therefore, GIN (Grouting Intensity Number) can be a good index with appropriate monitoring of pressure and volume of grout. In this paper, we investigate the effects of joint roughness (JRC) and rheology of cement material during the infiltration of cement grout material into rock joint through CFD (computational fluid dynamics) analyses. With rough joint surface and increase of WC ratio, the frictional resistance during the grouting increases. The results have been summarized with polynomial correlations.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.2
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• pp.1508-1512
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• 2018

This study was conducted to examine the effect of joint mobilization on forward head posture and to propose an effective method to improve correct body posture and balance. A total of eight patients from a Maitland-applied group (n=8) received mobilization therapy to increase the mobility of the cervical joint, with Maitland's movement grade III intensity for 30 seconds of treatment and 30 seconds of rest, for ten intervals, three times a week for four weeks. The craniovertebral angle (CVA) changes before and after the intervention with the Maitland technique were measured as $56.85{\pm}2.31^{\circ}$ before, $63.23{\pm}2.23^{\circ}$ two weeks after, and $64.98{\pm}1.27^{\circ}$ four weeks after joint intervention. There were significant CVA changes before and after the Maitland technique (P <.05). The results of this study suggest that the Maitland technique is useful for improving the head vertebral angle in patients with forward head posture.