• Journal of Oral Medicine and Pain
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• v.41 no.3
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• pp.137-143
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• 2016

Posterior disk displacement (PDD) of the temporomandibular joint (TMJ) is a rare condition and most descriptions of TMJ PDD are about the adhesion of superior TMJ in which the position of disk is relatively posterior to anteriorly translated condyle in open mouth position. However, there have been reports about truly posteriorly positioned disk to the condyle in closed mouth position. This type of PDD has been classified into three subtypes-thin flat disk type, grossly posterior displaced disk type, and perforated disk type. Here, we report two rare cases of TMJ PDD, one with thin flat disk and one with perforated disk. Its possible etiology, pathogenetic mechanisms, related signs and symptoms, differential diagnoses, and treatments were reviewed and discussed.

• 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.

• Imaging Science in Dentistry
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• v.31 no.2
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• pp.93-99
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• 2001

Purpose: To analyze the possible association between magnetic resonance imaging signal intensity of temporomandibular joint disk and posterior attachment, and the type and extent of disk displacement, disk configuration, effusion and clinical signs in patients with internal derangement. Materials and Methods: Magnetic resonance images of the 132 temporomandibular joints of 66 patients with temporomandibular joint displacement were analyzed. The clinical findings were obtained by retrospective review of the patients' records. The type and extent of disk displacement, disk configuration and effusion were evaluated on the proton density MR images. The signal intensity from the anterior band, posterior band and posterior attachment were measured on MR images. The associations between the type and extent of disk displacement, disk configuration, effusion and clinical signs and the MR signal intensity of disk and posterior attachment were statistically analyzed by student's t-test. Results: Of 132 joints, 87 (65.9%) showed anterior disk displacement with reduction (ADR) and 45 (34.1%) showed anterior disk displacement without reduction (ADnR). The signals from posterior attachments were lower in joints with ADnR than those of ADR (p<0.05). The results showed statistically significant (p<0.05) association between the type and extent of disk displacement and disk configuration, and decreased signal intensity of posterior attachment. There were no statistical associations between pain, noise and limited mouth opening, and signal intensity of disk and posterior attachment. Conclusions: The average signal from posterior attachment was lower in joints with ADnR than that of ADR. The type and extent of disk displacement and disk configuration appeared to be correlated with the signal intensity from posterior attachment.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.2
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• pp.335-344
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• 1993

The purpose of this study was to clarify the spatial relationship of temporomandibular joint and to an aid in the diagnosis of temporomandibular disorder. For this study, three-dimensional images of normal temporomandibular joints were reconstructed by computer image analysis system and three-dimensional reconstructive program integrated in computed tomography. The obtained results were as follows: 1. Two-dimensional computed tomograms had the better resolution than three dimensional computed tomograms in the evaluation of bone structure and the disk of TMJ. 2. Direct sagittal computed tomograms and coronal computed tomograms had the better resolution in the evaluation of the disk of TMJ. 3. The positional relationship of the disk could be visualized, but the configuration of the disk could not be clearly visualized on three-dimensional reconstructive CT images. 4. Three-dimensional reconstructive CT images had the smoother margin than three-dimensional images reconstructed by computer image analysis system, but the images of the latter had the better perspective. 5. Three-dimensional reconstructive images had the better spatial relationship of the TMJ articulation, and the joint spaces were more clearly visualized on dissection images.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.136-142
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• 2006

Temporomandibular joint(TMJ) disorders have characteristic clinical findings such as pain, joint sound, and abnormal jaw function. With the rapid progress in TMJ imaging techniques, magnetic resonance imaging(MRI) especially provides the clinician and researcher with the ability to evaluate TMJ disorders(effusion, anterior disk displacement) and the hard and soft tissue of the TMJ. In order to manage the internal derangement of TMJ such as anterior disk displacement, the so-called appliance therapy is commonly used. This technique became the treatment of choice before surgical intervention by many practitioners. The purpose of the present study was to evaluate and determine the efficacy of anterior repositioning splint by means of the change of the position of the disk through pre- and post-treatment MRI. MRI and clinical symptom were carefully recorded in TMJ disorder patients. The relationship between TMJ symptoms such as pain, clicking sound, and disk displacement and effusion in MRI were analyzed. Then, splint therapy was applied for 3 months according to our protocol; at day 1, patients should wear 24 hours, in order to accomodate the splint and then, wearing time is reduced to 12 hours per day for one month. During next 2 months, it is tapered to 8 hours per day according to the evaluation of the clinical symptoms. Post-treatment MRI was obtained after 3 month protocol. This treatment strategy improved the clinical symptoms of TMJ disorder, and effusion and articular disk position showed a significant change. In conclusion, a treatment modality using an anterior repositioning splint therapy is an appropriate method for temporomandibular disorder patients.

• The Journal of Korean Academy of Prosthodontics
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• v.17 no.1
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• pp.35-46
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• 1979

A number of experimental studies have been carried out in order to clarify the question as to how temporomandibular joint adapt to the changes of mandibular movement and occlusal equilibration. Recently, the studies on the interrelations between anatomical structure of temporomandibular joint and the state of occlusion have been actively performed in dentistry particularly in prosthodontic field. Author performed extraction of unilateral mandibular molars in 30 mature male rats, and observed histological changes of temporomandibular joint through the light microscope. Following results were obtained. 1. The loss of unilateral teeth gave rise to the changes in the location of condylar head, that is, interior displacement of condylar head in the extraction side and upper displacement in the non-extraction side. 2. Articular disk was compressed by the interior surface of condylar head, resulting in its extension below the condylar neck in the extraction side, and the histological arrangement of the compressed area showed irregular feature. 3. The extension of articular disk below the condylar neck was accompanied with the contraction of muscle fibers which were originated from the articular disk. 4. The cartilage layer of articular fossa to the exterior of the extraction side showed hypertropy. 5. Early in the experiment, the inernal extremity of condylar head of extract ion side showed bone resorption, and cartilage layer of condylar head showed hypertropy. At 12 weeks after experiment, the condylar surface showed flattened, and the cartilage layer of condylar head was replaced by the compact bone. 6. The articular disk showed the formation of pannus in the extraction side as well as in the non-extraction side. 7. The occlusal disturbance due to unilateral missing teeth has brought about the non-inflammatory retrogressive change and osteoarthrotic change late in the experiment.

• 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.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.2
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• pp.113-122
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• 1993

In recent years the relationship between occlusal stability, mandibular position and temporomandibular joint function has been greatly emphasized. Anterior repositiong splint has been used for the purpose of correcting a disk-condyle in coordination, so we have usually wed it in ease of the click of the temporpmandibular joint. We have used anterior repositioning splint in 28 patients who have chief-complain of click in symptoms of the temporomandibular joint arthrosis. At the patients who had long-lasting symptom and sign, late click or degenerative change of the temporomandibular joint, the anterior repositioning splint had less effect on than we had expected. So we are now to report that we must pay attention to use of anterior repositioning spint.

• Journal of Yeungnam Medical Science
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• v.12 no.1
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• pp.141-148
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• 1995

The Magnetic resonance imaging has been used widely to evaluate the disk position without any interruption of the TMJ structures, and the dynamic MRI presenting computed serial imaging or the video-recorded simulation images is thought to be very effective to evaluate the disk position under function. This is to study the correlation between the clinical diagnosis and the findings of dynamic MRI for diagnosis of internal derangement of the 7 patients were examined clinically, and the movement of TMJ meniscus was reviewed in the dynamic MRI. MRI was very reliable to diagnose the amount of anterior displacement of articular disc, the structural abnormality of temporomandibular joint, the cause of functional limitation, and to differentiate the muscle related pain & dysfunction.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.155-169
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• 1998

The purpose of this study was to prove the relationship between arthrographic and clinical features in temporomandibular joint disorders. In order to carry out this study, ninety-eight arthrographic examinations of temporomandibular joints were performed on eighty-two patients who had the temporomandibular joint disorders. As the arthrographic examination, the cases were classified in three groups, disk displacement with reduction, disk displacement without reduction, within normal limit. After this, the cases were clinically examined, and the results were compared and analyzed in each other group. The obtained results were as follows; 1. As the classification by arthrographic examination, three groups (disc displacement with reduction, disc displacement without reduction, within normal limit) were 41 ％, 54％, 5％ of total cases in this study, respectively. 2. The third decade(65％) was most frequent in this study. The average age of each group (disc displacement with reduction, disc displacement without reduction, within normal limit) was 24, 28, 21, and disc displacement without reduction group was higher than any other group. 3. In the chief complaint, pain was the most frequent in all three groups. Joint sound was also frequent in disc displacement with reduction group, but in disc displacement without reduction group, limitation of mouth opening was more frequent. 4. Of the various pain, the movement pain was most frequent ( 61 ％) in this study. In joint sound, click(63％) was the most frequent in disc displacement with reduction group, but sound history(42％) and no sound (31 ％) were more frequent in disc displacement without reduction group. 5. The average maximum opening of each group (disc displacement with reduction, disc displacement without reduction, within normal limit) was 44mm, 32.9mm, 44mm, and disc displacement without reduction group was less than any other group. 6. The masticatory disturbance of each group (disc displacement with reduction, disc displacement without reduction, within normal limit) was 53％, 79％, 40％, and the trauma history of each group was 50％, 40％,60％.