Chapter 26: Temporomandibular Disorders

Temporomandibular disorders comprise a group of interconnected conditions affecting the temporomandibular joint, the muscles involved in mastication, and surrounding anatomical structures. The temporomandibular joint functions as a complex, stress-bearing synovial articulation lined with fibrocartilaginous tissue, and pathology typically originates from damage to retrodiscal tissues, capsular ligaments, or inflammation and muscular hypertonicity within the masticatory system, a condition termed myofascial pain syndrome. Anterior disc displacement or occlusal misalignment can trigger joint locking and mechanical dysfunction, sometimes producing referred symptoms including otalgia, tinnitus, vertigo, and auditory disturbances. Epidemiologically, temporomandibular disorders affect approximately one-third of the adult population, though only a small percentage pursue clinical intervention, with peak incidence occurring between the second and fourth decades of life. Female individuals and non-Hispanic white populations demonstrate higher prevalence rates, while documented risk factors encompass mechanical triggers such as bruxism, underlying psychiatric conditions including mood disorders, and autoimmune diseases particularly rheumatoid arthritis, which shows comorbidity rates exceeding fifty percent. Clinical presentation characteristically involves unilateral, dull facial pain radiating toward the ear, temporal region, or cervical structures, accompanied by jaw dysfunction manifesting as clicking, popping, and locking sensations that typically intensify upon waking and during mastication. Physical examination should incorporate bimanual palpation of the joint and masticatory muscles to identify tenderness, swelling, restricted mandibular opening below thirty-five millimeters, asymmetrical jaw trajectories, and palpable crepitus. Diagnostic evaluation requires systematic exclusion of serious pathology through red flag assessment, laboratory testing including complete blood count, inflammatory markers, and thyroid function, along with imaging modalities such as panoramic radiographs for dental evaluation, computed tomography for osseous detail, and magnetic resonance imaging for soft tissue and disc visualization. Management prioritizes pain reduction and functional restoration through integrated pharmacological and nonpharmacological approaches, including dietary modification toward soft foods, thermal modalities, supervised physical rehabilitation, behavioral interventions such as biofeedback, and occlusal splinting. Pharmacological treatment initiates with nonsteroidal anti-inflammatory medications over two weeks, with muscle relaxants for acute spasm and tricyclic antidepressants for chronic pain particularly when psychiatric comorbidity exists, while opioid and benzodiazepine prescription remains contraindicated due to abuse liability. Advanced interventions including trigger point injection and surgical reconstruction address refractory presentations, necessitating specialist referral for maxillofacial surgical evaluation.