Changes in disc status in the reducing and nonreducing anterior disc displacement of temporomandibular joint: a longitudinal retrospective study

Abstract

Treatment procedures for anterior disc displacement (ADD) of temporomandibular joint (TMJ) are far from reaching a consensus. The aim of the study was to evaluate disc status changes of anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR) comparatively, to get a better understanding of the disease progress without intervention. This longitudinal retrospective study included 217 joints in 165 patients, which were divided into ADDWR group and ADDWoR group based on magnetic resonance imaging (MRI) examination. The joints were assessed quantitatively for disc length and displacement distance at initial and follow-up visits. Disc morphology, which was classified in 5 types, was also evaluated. Paired t-test and Wilcoxon signed rank test were used to assess intra-group differences and independent t-test for inter-group differences. Moreover, analysis of covariance was applied to analyze influential factors for changes in disc length and displacement distance. According to our results, discs tended to become shorter, move further forward and distort more seriously in ADDWoR group than in ADDWR group after follow-up. Moreover, discs were prone to become shorter and more anteriorly displaced in teenagers, type I and III morphologies, advanced Wilkes stages, or those with joint effusion. Follow-up period seemed to be not critical.

Temporomandibular joint disc displacement with reduction: a review of mechanisms and clinical presentation

“…Another study with 92 TMJ from patients with DDWR (mean age 20.76 years) that underwent a follow-up of 9.38 months without treatment, showed that only 6 (6.5%) TMJ evolved into DDWoR. In the remainder, 86 (93.5%) DDWR temporomandibular joints, the disc length was evaluated, and the results showed a reduction of 0.66±0.97 mm after the follow-up (in the same study, 131 TMJ with DDWoR showed a decrease of 1.36±1.48 mm in disc length) 44 . A recent longitudinal study showed that of the 155 TMJ that had baseline diagnoses of normal/indeterminate or DDWR (and who received no treatment), 137 (88.4%) had no change in diagnosis 7.9 years later, on average; this result collaborates with previous studies that state that the classic model of DDWR progression to another internal derangement (such as DDWoR) is uncommon 45 …”

Yang’s Classification of Juvenile TMJ Anterior Disc Displacement Contributing to Treatment protocols

“…In our clinic, we also found that patients with ADD often had condylar resorption of the TMJ. Besides, the longer ADD history, the more severe condyle resorption and dentofacial deformities 32,33 . All of the above-mentioned results indicate that juvenile ADD is a major causative factor for condylar resorption resulting in mandibular asymmetry and retrognathia.…”

“…We think this is because the disease course is relevant to our stage. That means the longer disease course, the higher ADD stage 33 . However when ADD patients were processed by suitable treatments, their prognosis became reversed.…”

Changes in temporomandibular joint spaces after arthroscopic disc repositioning: a self-control study

“…MRI images were taken perpendicular (sagittal images) and parallel (coronal images) to the horizontal long axis of the condyle. Detail parameters about the TMJ MRI scans were reported in our previous study 17 21 .…”