Per-Lennart Westesson

Classification and prevalence of temporomandibular joint disk displacement in patients and symptom-free volunteers

The purposes of this study were to develop a classification system for disk displacement in the temporomandibular joint (TMJ) and to study the prevalence of the various types of TMJ disk displacement in patients and symptom-free volunteers. The study was based on bilateral MRIs of 243 patients and 57 symptom-free volunteers. Eight different types of disk displacements were identified in addition to the superior disk position and a tenth indeterminate category. Superior disk position was observed bilaterally in 18% of the patients and bilaterally in 70% of the symptom-free volunteers.

Anatomic disorders of the temporomandibular joint disc in asymptomatic subjects

PURPOSE This study determined the prevalence and specific anatomic types of disc displacement in asymptomatic versus symptomatic subjects using magnetic resonance imaging (MRI). PATIENTS AND METHODS A detailed MRI assessment was performed on both temporomandibular joints (TMJ) in 76 volunteers and 102 successive patients. Attention was placed on the functional aspects of disc displacement with and without reduction and on the anatomic aspects of disc displacement in the anterior, lateral, medial, anterolateral, and anteromedial directions. These assessments were made by radiologists blinded to the clinical information. RESULTS Disc displacement was found in at least one joint in 25 of 76 (33%) of asymptomatic subjects and 79 of 102 (77%) of symptomatic subjects. The anatomic types of disc displacement between groups was not statistically significant (P = .55). However, there was a significant difference between asymptomatic and symptomatic subjects, with an odds ratio of 3.91 for disc displacement with reduction and 42.71 for disc displacement without reduction (P < .001). CONCLUSION Although there was a 33% prevalence of disc displacement in asymptomatic volunteers, there was a highly significant difference in the prevalence of internal derangement in symptomatic subjects. Bruxing was statistically linked to TMJ disc displacement and could explain the anatomic variation in abnormal disc position.

Imaging of the temporomandibular joint: a position paper of the American Academy of Oral and Maxillofacial Radiology.

Various imaging techniques for the temporomandibular joint are discussed with respect to uses, strengths, and limitations. An imaging protocol is outlined for evaluating patients with a wide variety of temporomandibular joint related signs and symptoms.

Reliability of a negative clinical temporomandibular joint examination: Prevalence of disk displacement in asymptomatic temporomandibular joints☆

Unilateral temporomandibular joint arthrography was performed in 40 healthy volunteers with asymptomatic and clinically normal temporomandibular joints. Thirty-four joints (85%) showed superior disk position, and six joints (15%) were radiographically abnormal with displacement of the disk. Thus, two showed anterior displacement, one showed rotational anterolateral displacement, one showed rotational anteromedial displacement, one showed sideways lateral and one showed sideways medial displacement. Thus, a negative clinical examination for temporomandibular joint internal derangements may involve a risk of being false-negative. All but one of the joints showed normalization of disk position during opening, and it is suggested that lack of functional disturbances accounts for the freedom of symptoms.

Natural Course of Untreated Symptomatic Temporomandibular Joint Disc Displacement without Reduction

In some patients with disc displacement without reduction, the symptoms of pain and decreased range of motion have been observed to resolve spontaneously over time without treatment. The natural history of this condition, however, is not well-understood. Thus, to study the natural course of disc displacement without reduction, we followed 40 patients without treatment for a period of 2.5 years. The diagnosis was established by history and physical examination and confirmed with magnetic resonance (MR) imaging. After 2.5 years, 43% of the patients were asymptomatic, 33% had decreased symptoms, and 25% of the patients showed no improvement or had required treatment. MR evidence of osteoarthritis and advanced stages of internal derangement at the initial evaluation was associated with a poor prognosis. The result of this prospective cohort study indicated that approximately 40% of patients with symptomatic disc displacement without reduction will be free of symptoms within 2.5 years, one-third will improve, whereas one-quarter will continue to be symptomatic. This knowledge should be valuable for the treatment planning and evaluation of prognosis of patients with non-reducing symptomatic disc displacement.

Osteoarthritis and internal derangemen of the temporomandibular joint: A light microscopic study

To describe osteoarthritic changes of the temporomandibular joint (TMJ) and their relation to internal derangements, 22 randomly selected TMJ autopsy specimens were dissected and studied by light microscopy. Normal disc position was seen in eight joints, partial anterior displacement of the discs in eight joints, and complete anterior displacement of the discs in five joints; one joint had a perforated disc. Degenerative changes, such as horizontal splitting, clustering of chondrocytes, bone marrow fibrosis, sclerosis, erosion, cyst formation, and reduction in TMJ size, were found in 11 of the 14 joints with displacement or perforation of the disc and in four of the eight joints with normal disc position. Internal derangement appeared to be associated with osteoarthritis. The relations between remodeling, aging, internal derangement, and osteoarthritis are discussed.

Internal derangement of the temporomandibular joint: Morphologic description with correlation to joint function

Internal derangement of the temporomandibular joint has mainly been studied arthrographically from the standpoint of anterior disk displacement with or without reduction. Frequent clinical observations of disk deformation in joints with internal derangement implied the need for a systematic study of morphologic alterations associated with internal derangement. Therefore, morphology, internal derangement, and joint function were studied in 58 randomly selected autopsy specimens of the temporomandibular joint. The results showed that joints with superior disk position rarely demonstrated morphologic alterations. In joints with partially anterior disk position, disk deformation occurred somewhat more frequently (31%) and was consistently located in the part of the disk that was positioned anteriorly. Joints with completely anteriorly positioned disks showed disk deformation in 77% and irregularities of the articular surfaces in 65%. It appears that anterior disk position precedes disk deformation. Therefore, early causal treatment to correct symptomatic internal derangement appears indicated to decrease the possibility of development of disk deformation. Disk deformation was also closely associated with disturbed joint function and should therefore be an important consideration when one is planning treatment of internal derangement of the temporomandibular joint.

Prevalence of temporomandibular joint internal derangement in patients with craniomandibular disorders

To determine the prevalence of temporomandibular joint internal derangement in patients with signs and symptoms of craniomandibular disorders, bilateral imaging was performed in a consecutive series of 115 patients with signs and symptoms of craniomandibular disorders. Ninety patients (78%) had different stages of unilateral or bilateral internal derangement, and 25 patients (22%) had normal temporomandibular joints bilaterally. Out of 230 joints, 60 showed disk displacement with reduction, 8 showed disk displacement without reduction, and 29 showed disk displacement without reduction associated with anthrosis. The study indicates that almost 80% of patients with signs and symptoms of craniomandibular disorders have different forms of internal derangement.

Magnetic resonance imaging of the temporomandibular joint Increased T2 signal in the retrodiskal tissue of painful joints

The cause of pain associated with TMJ disk displacement and internal derangement is unclear. In clinical work with MR imaging we have noted increased T2 signal from the retrodiskal tissue in some patients with TMJ pain and dysfunction. The purpose of this study was to analyze a possible association between pain and the T2 signal intensity from the retrodiskal tissue on MR images. The study was based on 48 joints in 33 patients referred for MR imaging of the TMJ. The T2 signal from the retrodiskal tissue was measured on the MR scanner and was correlated to the degree of pain. The results showed a statistically significant (p < 0.05) association between pain and increased T2 weighted signal. The T2 signal intensity ranged between 251 and 478 and was highest in the painful joints and lowest in the joints without pain. We conclude that the average T2 signal from the retrodiskal tissue is higher in painful joints than in nonpainful joints. This might reflect an increased vascularity of the joint tissue.

Double-contrast arthrotomography of the temporomandibular joint: Introduction of an arthrographic technique for visualization of the disc and articular surfaces☆

A technique for double-contrast arthrotomography of the temporomandibular joint was developed. Iodine contrast medium and air were injected into both joint compartments of 105 patients. Lateral tomography using a multi-film cassette was performed. The double-contrast arthrotomography depicted, with good definition, the configuration and position of the disc, its attachments, and the articular surfaces. Postarthrographically, the patients experienced transient discomfort, but there were no serious complications. Double-contrast arthrotomography facilitates the diagnosis of internal derangements by improving the radiographic image of the intra-articular anatomy.