• Imaging Science in Dentistry
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• v.32 no.2
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• pp.67-73
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• 2002

Purpose: To examine the possible relationship between condylar position and disk displacement in the temporomandibular joint. Materials and Methods: 79 temporomandibular joints in 40 patients having temporomandibular disorders were classified into three categories: no disk displacement (NDD) , disk displacement with reduction (DDWR), and disk displacement without reduction (DDWOR). Disk positions were assessed from clinical and MRI findings. The relationship between the three categories and condylar positions was evaluated using lateral individualized corrected tomography. Results: Clinical findings regarding the relationship between condyle and disk positions having anterior, centric, and posterior positions were 27%, 27%, and 46%, respectively, in NDD, 43%, 17%, and 40%, respectively, in DDWR, and 44%, 22%, and 34%, respectively, in DDWOR. There were no significant differences in condylar positions between each of the groups (P>0.05). In the relationship between condyle and disk positions with MRI findings, anterior, centric, and posterior positions were 38%, 38%, and 24%, respectively, in NDD, 29%, 21%, and 50%, respectively, in DDWR, and 44%, 9%, and 47% respectively, in DDWOR. There were significant differences in the condylar positions when MRI was utilized (P<0.05) Conclusion: There was a significant correlation between the condyle and disk positions with MRI findings on lateral individualized corrected tomography.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.9 no.1
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• pp.13-18
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• 1979

The purpose of this study was to investigate the radiographic images of Temporomandibular joint trouble patients. This study included 186 patients with the chief complaints of TMJ pain and dysfunction. Their age ranged from 17 to 68 years. All patients were identified in the department of Dental mary of College of Dentistry, Seoul National University, Apr. 1978 to Jun. 1979. The author has observed the radiographic variations of two positions of condylar head taken by modified transcranial oblique-lateral projection, which are one in centric occlusion and the other in 1 inch(2.54㎝) mouth open. The results were obtained as follows; 1. In centric occlusion, the distances and positional relationship between the summit of condylar head and the deepest point of articular fossa revealed more or less large variations; Normal range is of 37.9%, anterior displacement of 37.3% and posterior displacement of 22.6%. 2. In the horizontal movement of condylar heads when on 1 inch mouth open, it was revealed that normalrange was of 46.5%, anterior displacement of 12.3%, posterior displacement of 41. 1 %. 3. In the positional interrelationship of both condylar heads when on 1 inch mouth open, it was revealed that symmetry(71. 5%) occurred approximately 2.5 times as many as asymmetry. 4. In both centric occlusion and 1 inch mouth open, it was showed that almost all estimated figures were greater in male than in female, and in the horizontal movement of condylar head when on 1 inch open, it was showed that hypermobility was dominant in male and hypomobility in female.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.12 no.1
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• pp.15-20
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• 1982

The purpose of this study was to investigate the normal range of condylar displacement of normal adults. The author has observed two roentgenographic images of condylar head taken by transcranial projection. Two roentgenographic images are centric occlusion and centric relation. The results were obtained as follow: 1. Total subjects are 72 condyles. The condylar displacement from centric relation to centric occlusion was shown in 65 condyles (90%) anteriorly. 59 condyles (82%) inferiorly. Two condyles (3%) showed neither anterior displacement nor inferior displacement. 2. The average displacement of right condyles was 0.54±0.06㎜ anteriorly, 0.34±0.05㎜ inferiorly. The average displacement of left condyles was 0.74±0.09㎜ anteriorly, 0.45±0.05㎜ inferiorly. 3. The subjects of synmetrical displacement are 7 cases (20%) anteriorly, 2 cases (6%) inferiorly.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.1
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• pp.93-107
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• 1997

Magnetic resonance imaging has been used in the temporomandibular joint(TMJ) primarily to define morphology and positional relationship of associating structures. This report examines signal intensity characteristics of the posterior attachment as they related to the severity of internal derangement. Fifty six joints in 35 patients with a history of TMJ dysfunction were imaged writ MR using $T_1$-weighted spin echo sequence. According to disk position, ability to reduction, and the presence of osteoarthritis, the joints were categorized into three groups. A group 1 was anterior disk displacement with reduction; a group 2 was anterior disk displacement without reduction; a group 3 was anterior disk displacement without reduction and condyle had osteoarthritic change. The control group was determined by the clinical absence of any signs or symptoms of current or past TMJ pain and dysfunction. Calculated the relative value of MR signal intensity in posterior attachment and disk to cerebral cortex of temporal lobe by means of computer program, we have compared them with each groups. The result showed statistically little significant difference of disk signal intensity among each groups. but, signal intensity from posterior attachment in group 2 and 3 were significantly(p<0.05) decreased than control group. this might reflect an fibrosis or hyalinization of posterior attachment, which was part of remodeling process that occurs in disk displacement without reduction. However, this study could not demonstrate histologic confirmation of the decreased signal intensity in the posterior attachment. So, further investigation could be needed to understand the association between them.

• The korean journal of orthodontics
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• v.45 no.1
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• pp.20-28
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• 2015

Objective: The purpose of this study was to observe stress distribution and displacement patterns of the entire maxillary arch with regard to distalizing force vectors applied from interdental miniscrews. Methods: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. The displacement of each tooth was calculated on x, y, and z axes, and the von Mises stress distribution was visualized using color-coded scales. Results: A single distalizing force at the archwire level induced lingual inclination of the anterior segment, and slight intrusive distal tipping of the posterior segment. In contrast, force at the high level of the retraction hook resulted in lingual root movement of the anterior segment, and extrusive distal translation of the posterior segment. As the force application point was located posteriorly along the archwire, the likelihood of extrusive lingual inclination of the anterior segment increased, and the vertical component of the force led to intrusion and buccal tipping of the posterior segment. Rotation of the occlusal plane was dependent on the relationship between the line of force and the possible center of resistance of the entire arch. Conclusions: Displacement of the entire arch may be dictated by a direct relationship between the center of resistance of the whole arch and the line of action generated between the miniscrews and force application points at the archwire, which makes the total arch movement highly predictable.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.237-254
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• 2011

Objective: The purpose of this study was to compare the displacement patterns shown by finite element analysis when the maxillary anterior segment was retracted from different orthodontic miniscrew positions and different lengths of lever arms in lingual continuous and segmented arch techniques. Methods: A three dimensional model was produced, the translation of teeth in both models was measured and individual displacement was calculated. Results: When traction was carried out from miniscrews in the palatal slope, lingual tipping of crowns and extrusion of the maxillary anterior segment were found in both continuous and segmented arches as the lever arms were made shorter. With miniscrews in the midpalatal suture area, the displacement patterns were similar to the palatal slope, but bodily movement of the upper incisors was observed in both continuous and segmented arches with the lever arm at 20 mm. When lever arms were longer, there was less extrusion of the incisors and more buccal displacement of the canines. Such displacement was shown less in the continuous arch than the segmented arch. The second premolar showed crown mesial tipping and intrusion, and the molars showed distal tipping in the continuous arch. The posterior segment was displaced three dimensionally in the segmented arch, but the amount of displacement was less than the continuous arch. Conclusions: It is recommended that lever arms of 20 mm in length be used for bodily movement of the anterior segment. Use of continuous or segmented arches affect the displacement patterns and induce differences in the amount of displacement.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.235-250
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• 1990

Thirty-nine patients (forty-four joints) who had been diagnosed as having meniscus perforation of the temporomandibular joint by inferior joint space arthrography and had been treated by surgical procedures were evaluated retrospectively. Information of clinical findings, arthrotomographic findings and surgical findings was collected on a standardized form and evaluated. The results were as follows: 1. On the 34 patients of 38 joints which were surgically confirmed perforation of meniscus or its attachments of the temporomandibular joint, there were 29 females and 5 males (5.8:1). The average age was 36 years (range 17 to 70). 2. The common clinical findings of group that had meniscus displacement without reduction and with perforation were pain on the affected joint and limitation of mouth opening. In the group showing meniscus displacement with reduction and with perforation the common clinical findings were pain and clicking on the affected joint. 3. 32 joints (84.2%) were arthrotomographically anterior meniscus displacement without reduction and with perforation, 6 joints (15.8%) showed anterior meniscus displacement with reduction and with perforation. 4. Joints categorized arthrotomographically as having meniscus displacement without reduction and with perforation were less likely to have full translation of the condyle in comparison with the normal or meniscus displacement with reduction and with perforation groups. (p<0.05) 5.The arthrographic findings of 44 joints having meniscus perforation were compared with surgical findings, there were 6 false positive findings of meniscus perforation, the reliability of arthrographic findings of meniscus perforation was a 86.4% correlation with surgical findings. 6. On the site of perforations of 38 joints which were surgically confirmed perforation of meniscus or its attachments, twenty-three of perforations (60.5%) were in location at the junction of the meniscus and posterior attachment, forteen (36.9%) were located at the posterior attachment and one (2.6%) was at the meniscus itself.

• The korean journal of orthodontics
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• v.21 no.2 s.34
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• pp.419-432
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• 1991

The purpose of this study is to observe how the Class III intermaxillary elastics act upon the craniofacial structures of mixed dentition with anterior crossbites. The cephalometric headplafes of 16 childrens treated only with Class III elastics (C III elastics group) and 23 childrens treated with Class III elastics and Reverse pull headgear simultaneously (C III elastics + RPHG group) were traced, digitized and statistically analyzed. The results were as follows. 1 . Anterior displacement of maxilla was observed in both groups. 2. Simultaneous Class III elastics and reverse pull headgear group showed the counterclockwise rotation of maxilla, however Class III elastics group manifested no rotational change of maxilla. 3. Simultaneous Class III elastics and reverse pull headgear group showed the downward and backward rotation of mandible, however Class III elastics group manifested no rotational change of mandible. 4. Counterclockwise canting of occlusal plane, labial tipping of upper incisor and lingual tipping of lower incisor and mesial displacement of upper molar to pterygoid root vertical were observed in both groups.

• The korean journal of orthodontics
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• v.53 no.5
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• pp.289-297
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• 2023

Objective: To analyze the microimplant (MI) displacement pattern on treatment with a maxillary skeletal expander (MSE) using cone-beam computed tomography (CBCT). Methods: Thirty-nine participants (12 males and 27 females; mean age, 18.2 ± 4.2 years) were treated successfully with the MSE II appliance. Their pre- and post-expansion CBCT data were superimposed. The pre- and post-expansion anterior and posterior inter-MI angles, neck and apical inter-MI distance, plate angle, palatal bone thickness at the MI positions, and suture opening at the MI positions were measured and compared. Results: The jackscrew plate was slightly bent in both anterior and posterior areas. There was no significant difference in the extent of suture opening between the anterior and posterior MIs (P > 0.05). The posterior MI to hemiplate line was greater than that anteriorly (P < 0.05). The apical distance between the posterior MIs was greater than that anteriorly (P < 0.05). The palatal thickness at the anterior MIs was significantly greater than that posteriorly (P > 0.01). Conclusions: In the coronal plane, the angulation between the anterior MIs in relation to the jackscrew plate was greater than that between the posterior MIs owing to the differential palatal bone thickness.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.97-104
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• 2000

The temporomandibular joint arthrocentesis is indicated the 'closed lock' due to anterior disc displacement without reduction. It can be easily carried out under local anesthesia with little complications. We performed arthrocentesis to the 24 patients, 9 patients who suffered from acute or chronic closed lock with anterior disc displacement, 2 patients from temporomandibular joint dysfunction related to systemic disease and 13 patients from joint dysfunction with pain. We present the common clinical aspect of arthrocentesis that operator can be easily faced with and possible modifications of this method.