Immunohistochemical Profiling in Temporomandibular Disorders: A Systematic Review of Biomarker Patterns in Synovial Tissue.

Background: Temporomandibular disorders (TMD) are multifactorial conditions involving biomechanical dysfunction and progressive degeneration of the temporomandibular joint (TMJ) and surrounding tissues. Although affecting up to 36% of the population, their underlying molecular mechanisms remain incompletely understood. Immunohistochemical analysis of synovial biomarkers may help clarify processes involved in tissue degeneration and symptom development.

Objective: This systematic review investigates associations between immunohistochemical biomarkers in synovial tissue and morphological or symptomatic findings in TMD, with a focus on internal derangement and disc displacement.

Methods: A comprehensive literature search was conducted in MEDLINE/PubMed, EMBASE, Web of Science, and selected journals. Studies were screened according to PRISMA guidelines, and methodological quality was assessed using the Newcastle-Ottawa Scale. Due to heterogeneity across studies, a narrative synthesis was performed.

Results: Thirteen studies involving 493 patients (mean age: 42.2 years; 82% women) were included, analyzing 23 different biomarkers. Frequently examined markers included MMPs, COX-2, iNOS, interleukins, and VEGF. Several of these showed statistically significant correlations with histological, radiological, or clinical findings, suggesting roles in joint homeostasis, inflammation, and tissue remodeling associated with TMD.

Conclusion: Based on the reported associations with histological, radiological, and clinical findings, biomarkers were categorised into stage-specific and functional groups, underscoring their relevance for disease stratification and prognosis. By revealing disease-related patterns in progression and severity, synovial biomarkers have the potential to empower our understanding of the underlying mechanisms of TMD and contribute to more precise diagnostic and therapeutic approaches.