Correlation between bilateral TMJ MRI findings: A systematic review of the literature

The correlation between magnetic resonance imaging (MRI) signs and clinical findings has been highlighted in multiple studies. However, very little information is available on the correlation between the bilateral temporomandibular joints (TMJs) of the same individual. The majority of efforts in the clinical research setting have focused on the correlation between ipsilateral imaging and clinical findings, while less attention has been paid to the contralateral imaging findings of the anatomical structures.The objective of this paper was to review the existing literature that compares temporomandibular joint (TMJ) magnetic resonance imaging (MRI) findings from both sides of the same individual.In January 2024, a systematic search of the literature from major search engines (MEDLINE (PubMed), Scopus) was conducted to identify all peer-reviewed English-language studies that presented an MRI comparison of left and right TMJ data in the same patients. The articles were analyzed using a Population/ Intervention/Comparison/Outcome (PICO) format.The search terms "temporomandibular joint" AND "magnetic" AND "resonance" yielded 2,561 results. Only 2 papers met the established inclusion criteria. The results of the papers included in the systematic review were not comparable due to differences in the evaluation of the TMJs, which prevented a meta-analysis. Manfredini et al. identified a statistical correlation between disc displacement, osseous changes (OC) and joint effusion (JE) between the joints of the contralateral sides. Koca et al. observed a significant difference in TMJ MRI findings between the painful and non-painful sides of each individual in a bruxism group and a control group (p = 0.001, p < 0.001 and p = 0.004, p < 0.001, respectively).The studies on the correlation between the right and left TMJs remain scarce. A comparative analysis of the 2 sides of the TMJ in individual patients is rarely reported.The review did not identify a common result for the findings of the contralateral TMJs in the 2 articles included.