Temporomandibular joint (TMJ) disorders
Causes of TMJ pain
Intra-Articular Causes
1. Inflammatory conditions
Caused by direct trauma, such as a blow to the chin/jaw or indirect trauma, a whiplash injury, heavy chewing, grinding (bruxism), clenching of the jaw or loss of dental height due to worn down or missing teeth.
2. Internal derangement
Resulting in structural changes within the joint. This can be caused by direct or indirect trauma, such as long-term clenching or grinding, heavy or hard chewing or prolonged periods of mouth opening, such as a dental procedure or a general anaesthetic.
3. Arthritis
Degenerative arthritis can occur in the TMJ and is usually seen in the over 50’s.
Inflammatory joint diseases can affect the TMJ, including rheumatoid arthritis.
4. Hypermobility
Can result in excessive movement of the jaw and the articular disc. This will likely result in deviation of the jaw away from the affected side.
Long term hypermobility can cause the articular disc to elongate and degenerate. The disc can then fail to reduce on closing, causing the TMJ to become stuck in an open position (Open Lock). This can often occur after opening the mouth to an extreme position, such as when singing or yawning or after a prolonged dental procedure.
Extra-Articular Causes
1. Muscle Spasm
Muscle Spasm can cause significant pain and limitation of movement of the jaw (trismus). It often affects one or more muscles, commonly the muscles of mastication (chewing); masseter, temporalis and the pterygoid muscles. Causes include prolonged dental procedures or anaesthetics where the mouth has been held open for extended periods of time, stress, bruxism (grinding) and postural dysfunction.
2. Fractures
Fractures of the mandible often occur at the mandibular symphysis or the condylar neck. The mechanism of injury can be a blow to the jaw or a fall onto the chin. Treatment can usually begin within a week or two of surgery to begin early mobilisation of the TMJ and to restore function.
Treatment of TMJ pain/pathology
Physiotherapy treatment is very effective in relieving and managing TMD, even when the symptoms are long-standing and/or severe.
With appropriate physiotherapy most patients will see a significant improvement in their symptoms within 3 to 6 weeks. Treatment will address the issues identified in the assessment:
Treatment may include soft tissue release to affected muscles as well as joint mobilisation.
Associated neck pain, headaches and posture correction will also be addressed where appropriate.
There is some evidence to supporting the use of splints to reduce long term degeneration of the TMJ, disc and teeth.
Education and implementation of a home exercise program, good sleep habits, stress management and diet modification will also be addressed where appropriate.
Manual Therapy
A systematic review published in 2015 supported the effectiveness of manual therapy on signs and symptoms of TMD. It showed that protocols of mixed manual therapy techniques, upper cervical mobilization or manipulation had considerable effect for reducing TMD symptoms.
Other causes of TMJ pain/TMD
It is important to be aware that there are other causes of pain and dysfunction in the oro-facial region that need to be distinguished from TMD.
1. Referred Pain
Noxious input from the trigeminal nerve, C1, C2 and C3 nerves all feed into the trigeminocervical nucleus in the brainstem and can cause referred pain to the jaw/TMJ region.
2. Neuropathic Pain
Trigeminal Neuralgia is characterised by severe, shooting pain in the distribution of one or more of the three branches of the trigeminal nerve (Cranial Nerve V). It is usually one sided.
3. Vestibular Dysfunction
Vestibular dysfunction can cause secondary headache and jaw pain. Dysfunction of the vestibular system can cause dizziness, vertigo, nausea, anxiety, neck pain and can also cause ear and jaw pain. As these symptoms can be similar to the symptoms of TMD, the vestibular system must be considered as a possible alternate cause of jaw pain.
Hanette Lemke is one of our Senior Physios and an expert in TMJ pain/disorders.
Do you suffer from TMJ/jaw pain?
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