TMD and Bruxism as Expressions of Central Regulatory State: The Functional Occlusion Regulated Model (FORM)

Temporomandibular disorder (TMD) and bruxism affect a significant portion of the adult population, yet why patients with comparable occlusal findings respond so differently to identical interventions remains unexplained by both structural and biopsychosocial frameworks. Traditional occlusal paradigms identified the importance of structural relationships but could not account for clinical variability. Biopsychosocial models advanced understanding of central regulation but lack the physiological specificity needed to connect regulatory state to functional jaw behavior. This paper proposes the Functional Occlusion Regulated Model (FORM), a hierarchical framework integrating central regulatory state, masticatory performance, and structure into a coherent model of jaw function, and identifies its clinical and research implications. Narrative synthesis of the peer-reviewed literature across masticatory physiology, autonomic neuroscience, pain neuroscience, and clinical dentistry was conducted; seventy-two references are cited. Converging evidence supports a three-tier hierarchy in which autonomic and neuromuscular regulatory state is proposed to shape masticatory performance, which influences how structural occlusal conditions are expressed and clinically experienced. FORM generates four testable predictions distinguishing it from existing models, and a preliminary clinical observation documents symptom resolution through regulatory intervention alone without occlusal modification, representing an early published dental observation of this connection. FORM provides a physiologically grounded framework for understanding treatment response variability and proposes central regulatory state as a potentially important upstream influence on functional jaw outcomes.