Assessment of temporomandibular joint bone changes associated with anterior disc displacement: An MRI cross-sectional study

Objective: This cross-sectional study aimed to evaluate the presence of bone changes on magnetic resonance imaging (MRI) scans of patients with temporomandibular joint (TMJ) anterior disc displacement (ADD) with reduction (ADDWR) and without reduction (ADDWoR).

Methods: TMJ-MRI scans were screened for the presence of ADD. 285 scans presented ADD, being further divided into ADDWR (n = 188) and ADDWoR (n = 97). Bone changes on the mandibular condyle and articular eminence were also assessed and computed. The chi-square test compared the association of these bone changes with the presence of ADDWR and ADDWoR, with a significance level of 5 %. Also, the prevalence ratio (PR) was calculated.

Results: In the mandibular condyle, subchondral cyst (p = 0.035, PR = 1.08) and bone edema (p = 0.044, PR = 2.40), more prevalent on ADDWR, and generalized sclerosis (p = 0.015, PR = 1.04), more prevalent on ADDWoR, presented significant association with ADD. On the articular eminence, generalized sclerosis (p = 0.015, PR = 1.04) and articular surface flattening (p = 0.003, PR = 1.19) presented significant association with ADD, both more prevalent on ADDWoR.

Conclusion: Bone changes are usual findings in TMJ with ADD diagnosis. The real influence of ADD is not fully clear, although clinicians should be aware of patients with this condition, to provide an early diagnosis and improve patient´s prognosis.