Temporomandibular Disorders and Occlusion
What the exam tests
The evidence linking occlusion and orthodontics to TMD, diagnostic classification, and conservative management.
Core rules
- The evidence does not support a causal link between orthodontic treatment and TMD; orthodontics neither causes nor reliably cures TMD.
- DC/TMD separates Axis I (physical diagnoses: myalgia, arthralgia, disc displacement, degenerative joint disease) from Axis II (pain-related and psychological factors).
- Common findings: clicking without pain, limited opening, deviation, muscle tenderness, bruxism.
- Occlusal factors such as crossbite, overjet, and CR–CO shift have weak or inconsistent associations with TMD; psychosocial factors are strong predictors.
- Management is conservative first: education, self-care, NSAIDs, occlusal splint, physiotherapy; surgery is reserved for selected cases.
- Imaging (panoramic, CBCT, MRI) is indicated when the diagnosis requires it, not as a screening routine.
Worked example
A 26-year-old requests orthodontics to 'fix' clicking and facial pain. Examination shows reciprocal click, normal opening, and muscle tenderness with exam stress. Reasoning: explain that clicking is common and not corrected reliably by alignment; offer conservative TMD management and reassess the orthodontic need separately, documenting the discussion.
Traps
- Promising TMD cure through occlusal correction.
- Diagnosing TMD from a single click.
- Ordering MRI without a clinical question.
- Overlooking psychological and sleep factors.