Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2012  |  Volume : 30  |  Issue : 2  |  Page : 158--160

Dynamic 3 T MRI of temporomandibular joint in diagnosing a stuck disk


J Sureka1, DV Reddy1, AK Karthik2,  
1 Department of Radiology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
2 Department of Dental and Oral Surgery (Oral and Maxillofacial Surgery),Christian Medical College and Hospital, Vellore, Tamil Nadu, India

Correspondence Address:
J Sureka
Department of Radiology, Christian Medical College & Hospital, Vellore-632004, Tamilnadu
India

Abstract

Magnetic resonance imaging (MRI) is the imaging modality of choice in the evaluation of internal derangement of the temporomandibular joint (TMJ). Dynamic MRI including the open and close mouth views in sagittal plane determine the exact position of articular disk and thus help to evaluate the joint for internal derangement. We also highlight the role of dynamic MRI of TMJ in diagnosis of stuck disk in a 17-year-old male who presented with symptoms of pain and difficulty in opening the mouth.



How to cite this article:
Sureka J, Reddy D V, Karthik A K. Dynamic 3 T MRI of temporomandibular joint in diagnosing a stuck disk.J Indian Soc Pedod Prev Dent 2012;30:158-160


How to cite this URL:
Sureka J, Reddy D V, Karthik A K. Dynamic 3 T MRI of temporomandibular joint in diagnosing a stuck disk. J Indian Soc Pedod Prev Dent [serial online] 2012 [cited 2020 Dec 5 ];30:158-160
Available from: https://www.jisppd.com/text.asp?2012/30/2/158/99994


Full Text

 Introduction



The most frequent cause of temporomandibular joint (TMJ) dysfunction is internal derangement. [1],[2] Internal derangement results from an abnormal relationship of the TMJ disk to the mandibular condyle, articular eminence, and glenoid fossa. 3 T dynamic magnetic resonance imaging (MRI) is well suited to evaluate the TMJ in all stages of internal derangement. [3] Optimal MR technique with dedicated coils and high spatial resolution provides exquisite tissue contrast for visualizing the soft tissue and periarticular structures of the TMJ. [3] Disk location is extremely important because a displaced disk is a critical sign of TMJ dysfunction. Closed and open sagittal and coronal MR imaging are useful for evaluating the dynamics of the TMJ and also accurate for determining the disk position. [1],[2],[3],[4]

 Case Report



A 17-year-old male presented to dental OPD with symptoms of pain and difficulty in opening the mouth since 6 months. He also complained of pain in his right ear region for the past 4 months. He had previous history of dentigerous cyst enucleation in 2007. He also underwent extraction with placement of removable partial dentures and root canal therapy. No past history of local trauma or TMJ surgery was reported. On examination, there was facial asymmetry and deviation of mandible toward right side while opening the mouth. There was severe limitation of jaw-opening. The mouth opening was only one and half finger breadth (15mm) noted. The condylar movement was not palpable on right side and clicking sound was elicited on left side.

Patient underwent MRI of TMJ to look for internal derangement. Dynamic MRI of TMJ in both open and closed mouth was done. On open mouth imaging, there was no condylar translation or movement of the disk on right side and it was fixed into its normal position as seen in closed mouth images. The posterior band of disk remained close to the mandibular fossa and over the condylar head [Figure 1]a and b. The posterior band was prominent and more hypointense compared with left side. The retrodiskal tissue was intact. The shape of the right mandibular condyle was altered as compare with left and appeared more broad with flattened superior and sloping anterior surfaces. Limited computed tomography (CT) sections showed osteophytes at the anterior aspect of condyle with narrowing of anterior joint space, subchondral irregularity and sclerosis of anterior part of condylar head. The right coronoid process was elongated with subtle ossification in the adjacent temporalis and lateral pterygoid muscles [Figure 2]a and b. Finally a diagnosis of stuck disk with osteoarthritic changes of right TMJ was made. We though this struck disk is probably due to intracapsular adhesions. The left articular disk maintained the normal morphology, positional, and functional relationship with condylar head [Figure 3]a and b. There was no joint effusion or synovial proliferation on either side. Patient was planned for TMJ arthrocentesis and/or eminectemy under general anesthesia. However, he did not turn up for treatment.{Figure 1}{Figure 2}{Figure 3}

 Discussion



The TMJ is a diarthrodial joint bounded by the glenoid fossa and articular eminence of the temporal bone above and the mandibular condyle below. TMJ disk is the most critical structure of the TMJ. It prevents the articular damage. It is located between the mandibular condyle and the temporal component of the joint and has three distinct parts seen on MRI. The thicker anterior and posterior bands and thin central part called the intermediate zone. [1]

The abnormal positional and functional relationship between the disk and the articulating surfaces is called as internal derangement of the TMJ. It may affect up to 28% of the population. [1]MRI is a valuable tool in the evaluation of internal derangements of the TMJ. [1],[2],[3],[4],[5] 3T MRI shows greatly improved resolution, including delineation of the all three components of the bilaminar articular disk not readily identified on 1.5T imaging. [3] It also delineates the subtle altered signal intensity of retrodiskal tissue. Increased T2-weighted signal intensity with enhancement in the retrodiskal tissue has been described in internal derangement. Further dynamic imaging in open and closed mouth in both sagittal and coronal oblique planes aids in determining the exact size, shape, position, and displacementof disk and as well as status of retrodiskal tissue, joints, and surrounding muscles and thus helps in detection of early TMJ internal derangement. [1],[2],[3],[4],[5] Hypertrophy/atrophy of the lateral pterygoid muscle, rupture of retrodiskal layers, joint effusion and synovitis can serve as indirect signs of TMJ dysfunction. [1] It is important for the radiologist to detect early MR imaging signs of dysfunction, thereby avoiding the evolution of this condition to more advanced and irreversible osteoarthritic stage. [1],[5]

On sagittal oblique MR, in a closed mouth position the larger posterior band is located over the condyle, in between 10 and 12 O'clock position, thin intermediate zone between the condyle and posterior part of the articular eminence while the anterior band is located under the articular eminence. With the open mouth,condyle reaches the apex of the articular tubercle and thin intermediate zone is located over the condyle and thus the posterior band and retrodiskal tissue are more clearly depicted. [1],[2],[3] The use of sagittal and coronal oblique MR imaging has been suggested to diagnose all types of abnormal disk displacements including anterior, anterolateral, anteromedial, lateral, medial, and posterior displacement. [1],[2],[5],[6],[7] TMJ function and range of motion again can be severely compromised by formation of intracapsular adhesions which can lead into a fixed position of disk in either a normal or a displaced position relative to the glenoid fossa and the articular eminence in both closed- and open-mouth positions the so-called 'stuck disk'as seen in our case. [1],[8] The exact pathogenesis of intracapsular adhesions has not been elucidated. However, there are various hypotheses on the mechanism of the etiology and the formation of adhesions. According to Kaminishi and Davis [9] hypothesis disk adhesions can result from synovitis causing fibrin deposition, which decreases joint lubrication. The resultant suction cup effect and immobilized joint causes the fibrin deposition to continue, with the formation of fibrous adhesions. Another theory ascribes the formation of adhesions to hematomas in the synovial membrane, which attract fibroblasts and fibrocytes to that area. [9],[10] The healing process is associated with the subsequent formation of scar-like fibrous tissue, promoting disk adhesion. [9],[10] The adhesion also may occur with the disk in its normal position and these patient display a severe mouth-opening limitation(15-25 mm) and rarely refers to a history of clicks as seen in our patient, in contrast to anterior disk displacement without reduction, in which the patient displays a less severe mouth-opening limitation (30-45 mm) and reports past clicks. [10]

The underlying etiology for TMJ dysfunction can be trauma, tumor, infection, prior TMJ surgery, orthodontic treatments, prosthodontic applications, or radiation. [1] It could be idiopathic where no underlying identifiable cause is noted. In our case, there was no history of trauma or previous TMJ surgery. However, patient had dentigerous cyst enucleation and prosthodontic applications that probably cause for his TMJ dysfunction. Further long standing neglected disk dysfunction can lead into the premature osteoarthritis, a more irreversible stage and that alters the final patient management.

 Conclusion



Dynamic 3 T MRI of TMJ allows noninvasive and accurate diagnosis of TMJ disk internal derangement problems. The disk can be stuck in a normal or displaced position and limits the normal degree of condylar translation, leading to restricted jaw opening. MRI enables a differentiation of early stages of disk displacement from more advanced and irreversible stages with osseous destruction, which could alter patient management.

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