Jaw pain used to always be blamed on the temporomandibular joint (TMJ), the hinge like connection that allows the lower part of the jaw to move up and down to open your mouth. It was thought this needed to be ‘fixed’ to get rid of the pain and the focus was on your bite (malocclusion). However now we look at the jaw more holistically which is why we use the term Temporomandibular Disorders (TMD), looking at multiple sources of jaw and facial pain from dental problems, migraine or anxiety and stress.
Jaw Anatomy
The TMJ is cleverly designed, the mandible (lower part of the jaw) is a horseshoe shape which fits into the two notches in the temporal bones. These notches allows the mandible to rotate so it hinges open as you open your mouth. The ends of the mandible (condyles) are wrapped in tough layers of fibrous cartilage that withstand shearing forces and then ligaments hold everything in place. We also have a small disc in between the mandible and temporal bone which acts a shock absorber.
We have a large number of muscle groups that have to carefully coordinate by contracting and relaxing at the right times. A very important muscle is the masseter muscles, a thick band that connects the mandible to the cheekbone on both sides of the face. It’s really important for chewing and is actually one of the strongest muscles in the body (pound for pound).
Classic TMD pain symptoms:
Dull ache
Jaw muscle stiffness
Limited movement or locking of the jaw
Radiating pain: side of the head, face and neck
Tension headaches
Crepitus (crackling, grinding sound) – however research has shown that sounds such as clicking or clunking do not mean there is a serious problem. Jaw noises are common and do not indicate in isolation a jaw disorder or need ‘fixing’.
Most common causes of TMD:
Arthritis - Sometimes it can be an actual joint problem such as a rheumatoid arthritis (joint inflammation) or osteoarthritis (wear and tear).
Derangement of joint - Sometimes it can be due to loose joints, for example you have EDS, where your ligaments won’t do their stabilisation job. Or it can be from a trauma like an accident or injury where your jaw is dislocated or disc displaced.
Myofasical pain - Most often the main problem is muscle pain.
- Sometimes this is from grinding teeth at night (one study found 78% of TMJ patients ground their teeth). Teeth grinding can be bad for your teeth and overuses your masseter and other jaw and facial muscles causing taut muscles which can lead to headaches. It is often related to stress, and people are unaware they are doing it.
- Sometimes its related to neck pain/postural imbalances that mean your jaw muscles are being held under tension for long periods of time causing overuse of the muscle or hyperactivity of the muscle, which in turn causes the muscle to fatigue and can cause pain
- Sometimes it can be due to central sensitisation in the nervous system related to other pain and health conditions, where basically the nervous system becomes overwhelmed and labels everything as a threat = pain. This plus postural imbalances are thought to be why there is such a link between jaw pain and headaches, migraine and cranial pain.
How can posture affect your jaw?
Researchers have noted that the activity in masticatory musculature’s (muscles involved in chewing and jaw positions) changes based on the head position, especially with the forward head posture (FHP). FHP consists of a slumped/rounded shoulder with the chin or head poking forwards, beyond its normal axis above the rest of the spine. It is thought this has a neuromuscular influence on the entire muscular system of the head and neck, and affects how the mandible closes. This in turn causes the cervical musculature to shorten, and the infrahyoid muscles stretch. This leads to abnormal amount of tension in the muscles and supporting structures.
Treatment for jaw pain
Mindful jaw use – eating soft foods, controlling bite size and avoiding jaw movements like wide yawning, chewing gum etc
Managing stress - Relaxation exercises and lifestyle adaptions
Pain management - Using heat or cold packs to manage pain (15-20 min at a time)
Medication - Anti inflammatory medications and muscle relaxants
Physiotherapy – massage/release work, stretching exercises and isometric (static) strength exercises and postural alignment
Splints – plastic guard on your upper and/or lower teeth from your Dentist
Dental treatment or orthodontics
Botox - still being clinically tests for use for the jaw, but already used for migraine treatment
Surgery or implants - last resort if conservative treatment has not worked
Video: A few examples of the type of exercises and stretches to relieve jaw pain
How can Physiotherapy help?
A physiotherapist can help assess your jaw by asking questions and looking at your body in particular posture, head and neck movements and your jaw function. Based on the findings treatment may include:
addressing postural imbalances, especially with forward head posture including deep neck flexor work
looking at your whole health and full body function
pain management techniques, and lifestyle adaptions to help reduce strain through the jaw
stretches - stretches you can do to help relieve jaw tension, focused on the mouth and jaw itself alongside any stretches required for the neck and upper body too
muscle release - internal (inside the mouth) and external ways to release trigger points or muscle tightness in the muscles in the head, neck and jaw
isometric strengthening - static strengthening exercises to build up muscle strength and stability for the muscles around the jaw
Can a splint 'fix' the problem?
It kind of depends what your underlying issue is and what the cause of your jaw pain, plus what other conservative methods you have tried first. Speak to your dentist about the different options and whether a splint can be beneficial for you. There have been multiple studies to see if using a splint is beneficial or specifically what type of splint is best practice.
Splints are thought to work by:
- preventing full occlusion, therefore preventing teeth clenching
- distributing the force normally generated by teeth clenching
- normalising ligament proprioception, proprioceptive fibres in the ligament send a message to the central nervous system to protect them from overload.
- relaxing the muscles, during excessive mandibular movement the muscles become hyperactive and then fatigues which causes pain. If the hyperactivity is stopped, the pain usually eases too.
- helps the mandibular condyles sit in the right position, preventing overloading due to muscle imbalance
- cognitive awareness, its thought that any type of splints acts a reminder for you to alter your behaviour so the harmful or abnormal muscle activity is decreased. It can help you find a more normal movement pattern again
Research on splints: limited overall and quite hard to find definitive research
Dao et al (1992) did a meta analysis of research and showed that using any type of splint over time reduced myofascial pain and improved quality of life, but was non-specific to the type of splint
Dao et al (1998) confirmed they should be used as an adjunct to other treatments alongside other management techniques
Srivastava (2013) looked at a specific type of a splint a ‘aqualizer’ which is a hydrostatic oral splint and found it was beneficial in treating jaw pain compared to other devices
Summary
The jaw is a complex joint and not to be treated in isolation but instead looked at in the same way we look at any other painful joint e.g. the shoulder, we look at all the structures around it. From the research it looks that a multi-modal approach works for managing jaw pain, with trying conservative methods such as stretches and exercises, before looking into more invasive measures. Care should involve a multidisciplinary team of dentists, physiotherapists and medical practitioners to work together.
References
Temporomandibular joint pain and dysfunction (Herb et al, 2006)
A new way for TMJ (Harvard Medical, 2009)
TMD/Facial Pain and Forward Head Posture (Goldstein, 2012)
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