How can I differentiate between TMJ disorder and other causes of orofacial pain in a primary care setting?

To differentiate temporomandibular joint disorder (TMD) from other causes of orofacial pain in primary care, focus on clinical features, history, and examination findings:

• History: TMD often presents with pain or reduced jaw function, sometimes associated with parafunctional activities such as teeth grinding, jaw clenching, or chewing gum. Ask about trauma, rheumatic joint disease, or recurrent dislocation, which may suggest more complex TMJ pathology requiring referral NICE CKS.
• Symptoms: TMD pain is typically localized to the temporomandibular joint and muscles of mastication, may fluctuate, and is often aggravated by jaw movement. Other orofacial pain causes may have different pain patterns, such as neuropathic pain (e.g., trigeminal neuralgia) characterized by sharp, electric shock-like pain triggered by facial touch NICE NG127.
• Examination: Assess mouth opening and jaw movement; markedly limited mouth opening (closed lock) suggests disc displacement without reduction, a feature of TMD NICE CKS. Look for joint sounds, muscle tenderness, and palpate for trigger points. Neurological examination is important to exclude facial numbness or abnormal neurological signs that suggest other causes NICE NG127.
• Red flags: Persistent facial numbness, abnormal neurological signs, or systemic symptoms warrant urgent referral for specialist assessment and imaging to exclude serious neurological or systemic conditions NICE NG127.
• Use a biopsychosocial approach: Consider psychosocial factors such as stress, anxiety, depression, and sleep dysfunction, which commonly influence TMD but may be less relevant in other orofacial pain causes NICE CKS.

Summary: Differentiate TMD by its characteristic jaw-related pain, functional limitation, absence of neurological deficits, and association with parafunctional habits. Other orofacial pain causes often have distinct neurological features, systemic signs, or different pain qualities requiring further investigation or referral NICE CKS,NICE NG127.