**3.1 Theoretical foundations of the system-structural analysis of the etiology and pathogenesis of temporomandibular disorders**

Temporomandibular disorders are heterogeneous chronic systemic diseases based on the articulatory norm's genetic, immunological, anatomical, morphological, and functional disorders. TMD is a symptom complex, the heterogeneity of which is characterized by a fluctuation of clinical symptoms, with periodic dominance of one of them. The pathogenesis of TMDs ends with the formation of specific pathological disorders in the articulation system:


The articulation system is formed by bones of the facial part of the skull, TMJ, chewing muscles, hyoid bone, and dentition in one of the types of physiological occlusion. The anatomical and functional criteria that provide the articulation system's physiological, cosmetic, and phonetic capabilities do realize within the articulation norm's phonetically determined boundaries. Therefore, anatomical and functional criteria of the articulatory norm do determine phylogenesis.

Identifying iatrogenic etiological risks (IERs) that form violations of anatomical and functional relationships in the articulation system is the main task of diagnosing TMDs. Iatrogenic etiological risks are preclinical forms of TMDs (predictors). However, undiagnosed preclinical forms transform into iatrogenic pathogenic factors and, further, into clinical forms of TMDs of iatrogenic etiology. As a result of the transformation, a new set of pathomorphological relationships do form, which clinically manifests itself as a newly formed symptom complex—TMDs (**Table 1**).


**Table 1.**

*The structure of clinically detected etiological factors in the pathogenesis of temporomandibular disorders.*
