Evaluation of Articular Eminence Morphology and Inclination in TMJ Internal Derangement Patients with MRI

Abstract

SUMMARY: Articular eminence morphology and inclination are reported to be two predisposing factors for the internal derangement (ID). The purpose of this study is to investigate the relationship between the inclination and morphology of the articular eminence and ID. The study included 70 temporomandibular joints with ID in 35 patients: 51 joints had disc displacements with reduction (DDWR) and 19 joints had disc displacements without reduction (DDWOR). All subjects underwent bilateral high resolution magnetic resonance imaging scans which were performed in the sagittal and coronal planes with mouths closed and opened. Articular eminence morphology was characterized as box, sigmoid, flattened, or deformed. Articular eminence inclination was measured at three positions: steep (from 60° to 90°), moderate (from 30° to 60°) and shallow (from 15° to 30°). The images were divided into two; DDWR and DDWOR, and these two criteria were compared. The images of the two groups were compared; while flattened form was occurred with the highest incidence in the DDWOR group, sigmoid form was the most frequent in the DDWR group and articular eminence inclination was found steeper than it was for the DDWOR group. The steepness of the articular eminence may not have a predisposing effect on the development of disc displacements.

Relationship between articular eminence inclination and alterations of the mandibular condyle: a CBCT study

“…These disorders may lead to degenerative bone diseases (DBDs) in both the condyle and the AE. 10 Articular bone diseases in the condyle may lead to adjustments in the AE inclination, as reported in some studies that have found joints with osteoarthritis to have more flat eminences. 7 Therefore, condyles with changes such as erosions, flattening, osteophytes, subchondral cysts and bone sclerosis may be correlated with less steep eminences, as a result of the close relation between these two structures.…”

“…4,9 This inclination can be measured in degrees, with normal values between 30º and 60º. 10 AEs below 30º are classified as flat and above 60º, as steep 9 , Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.…”

Correlation between articular eminence steepness measured with cone-beam computed tomography and clinical dysfunction index in patients with temporomandibular joint dysfunction

“…4,6 It is suggested that the articular eminence inclination might be an etiological factor in the development of TMJ disorders such as internal derangements. 6 The biomechanics of TMJ changes in the joints with steep eminences, so a steep articular eminence may lead to the temporomandibular joint dysfunction (TMD). 4,7 This theory may imply that eminectomy can be a treatment option to improve condyleedisk position and TMJ function.…”

“…5 The normal value of the articular eminence angle is between 30 and 60 . 4,6 Articular eminences with inclination angles <30 are considered "flat" and those having >60 are described as "steep." 4,6 It is suggested that the articular eminence inclination might be an etiological factor in the development of TMJ disorders such as internal derangements.…”

“…4,6 Articular eminences with inclination angles <30 are considered "flat" and those having >60 are described as "steep." 4,6 It is suggested that the articular eminence inclination might be an etiological factor in the development of TMJ disorders such as internal derangements. 6 The biomechanics of TMJ changes in the joints with steep eminences, so a steep articular eminence may lead to the temporomandibular joint dysfunction (TMD).…”