jaw dislocation

Jaw Dislocation

Dislocation refers to the displacement of the temporomandibular joint disc or condylar head with in the joint complex. Appropriate treatment resides in individual patient progression post injury, additional trauma and the extent of secondary complications and soft tissue contribution. Cases are typically seen through emergency department, Oral and Maxillofacial surgery, dentist or GP in some cases prior to referral to the clinic. However, in some cases we may also have direct contact without referral. The two typical kinds of dislocation we see include disc displacement without reduction (anterior or posteriorly placed) or condylar displacement secondary to compromised ligamentous integrity. 

 

Disc dislocation: 

We typically refer on for further imaging such as Cone beam CT or MRI (preferably) through either specialist or GP for Medicare rebate purposes and a diagnostic baseline. Conservative management is attempted in communication with the associated referrer and if they are unresponsive to conservative management early on, we ensure referral to Oral and Maxillofacial surgery for further assessment and management. We typically expect 45-55 mm of movement in depression ROM (opening availability). However the minimum normal range is 40 mm, and limited opening in combination with self-reported restriction on a side that may have previously resolved with a click is often reported by the patient. Typically there has been a history of intermittent clicking prior to this. Depending on the nature of the dislocation, it may reduce quickly in which case the emphasis is largely on strengthening the stabilizes and maintaining functionality to avoid subsequent displacement. More restricted closed lock conditions or chronic displacement often require more intensive capsular de-loading to release the posterior capsule and support reduction of the disc. This is accompanied with motor control exercises, pterygoid strengthening and postural retraining to encourage movement patterns, head positioning and a jaw posture. On initial assessment we expect ipsilateral condylar translation limitation due to blocking of the disc, and the contralateral condyle translating past the point of blocking. This limitation is felt quite clearly through palpation of the joint on that side. From a rehab perspective it is therefore critical to reinforce midline translation to avoid secondary capsular restriction, spasming and hyper-translation of the contralateral joint as a result of altered movement patterning. 

 

Author: Emily Fox


Locked jaw

What is a locked jaw?

A locked jaw occurs when the disc/the cartilage that sits behind the jaw joint slides forward and forms a mechanical block, which prevents your jaw from opening. When this occurs your movement is significantly limited and you are unable to fit more than 2 fingers in your mouth. 

Most people who experience a locked jaw have a history of sporadic clicking and when the jaw locks the clicking stops. It is important to note that if the clicking returns this is a good thing as the click itself is the disc/cartilage moving back into place as you overcome the mechanical block it has formed. It is also important to note that not every clicking jaw will become locked. A consistent, painfree, unchanging click that you have had for years is unlikely to become unstable and lock. It is the recent onset clicking, the sporadic clicking or changing click that warrants ongoing investigation. 

A locked jaw requires immediate referral to a Physiotherapist with experience in locked jaws and/or referral to an Oral Surgeon in cases where we are unable to relocate the disc. 

 

Author: Jessica Dowling


Fractured Jaw

Fractured Jaws explained

Motor vehicle accidents, sporting injuries and assaults are all common causes of jaw fractures. Jaw fractures are usually diagnosed at hospital with either an x-ray or CT scan. Depending on the type and location of fracture you will either require surgery or a period of immobility. During this period of immobility you will be required to go on a soft/liquid diet, avoid excessive jaw movements with brushing and speaking and you may also require splint therapy. During this time Physiotherapist treatment will primarily focus on your upper neck, which is commonly a secondary source of pain following jaw trauma and plays a large role in the posture, positioning and function of your jaw. Once your fracture has healed, your Physiotherapist will begin to mobilise and stretch your jaw joint to assist in regaining your opening range and jaw function. During this period you will also be required to do some exercises at home to regain the strength, control and coordination of your jaw muscles. 

 

Author: Jessica Dowling


Clenching and grinding

Do you suffer from Clenching or Grinding?

Bruxism is the term used to describe habitual clenching or grinding of the teeth and is a sign of oral para-function. Factors that contribute to the prevalence of bruxing include stress, anxiety, an abnormal or uncomfortable bite which is common in those suffering from sleep apnoea with 70% also complaining of bruxing.

Night bruxing may be identified by a partner or family member who can see or hear when you grind at night or, by a dentist who can identify physical signs such as excessive wearing of the teeth and scalloping of the tongue. Other signs of night bruxing include a dull headache and jaw tenderness first thing in the morning, as well as catching yourself with your teeth tightly closed at night.

The normal resting jaw posture during the day is with your tongue on the roof of the mouth, teeth apart, lips together, breathing through the nose. Day bruxing occurs when you find yourself resting with your teeth pressed firmly together.

Treatment of bruxism commonly involves splint therapy to unload the jaw during the night and to protect your teeth from further damage. Physiotherapy is most effective for day bruxism and typically requires retraining of the postural muscles of your neck and jaw.

 

Author: James Cumming


clicking jaw

What is a Clicking Jaw?

Some joints in your body will click from time to time. Sometimes they will hurt, sometimes they won’t. The jaw, like any other joint in your body, will click from time to time. Although, when the click in your jaw begins to cause pain, especially with movement, it’s time to start doing something about it!

So why does a jaw click? To answer that, we must first look at the anatomy of a jaw joint. The jaw is made up of four main components; the condyle (ball), the mandibular fossa (socket), the disc (cartilage sitting between the ball and socket) and a capsule which wraps around the whole joint.  For a smooth opening, the condyle rotates and shifts forward on the fossa, with the help of the disc which then forms a barrier between the two and stops any bone on bone grinding. Apart from forming a barrier between the condyle and the fossa, the disc also allows for the proper forward movement of the joint during opening. Without this forward movement, the condyle becomes stuck inside the fossa and is unable to complete full rotation.  

When a jaw begins to click, what is happening is the disc has come loose and slid forward and off the head of the condyle. Now, every time the jaw is attempting to open, it is forcing itself onto the disc, making a clicking noise during every opening.  In some people, this is due to slightly weaker ligaments and they can live their lives perfectly normally, with an albeit clicking jaw.  However, in others, this can be caused from a jaw dysfunction (eg. an altered bite pattern, teeth grinding, poor posture, trauma etc) and most likely needs to be addressed before regressing into a locked state. The jaw will become locked if the disc becomes too far displaced and the head of the condyle is unable to relocate on opening.  Normal opening for most adults, ranges between 45mm and 55mm.  In the instance of a locked jaw, the range generally drops below 30mm.  In most patients, this is quite painful and results in several functional issues, including difficulty in yawning, chewing and even talking sometimes.

In some circumstances, a clicking jaw can be a precursor to lock jaw which is why it’s important to get it looked at by a trained professional before it becomes any worse. At the Headache, Neck & Jaw Clinic, we are experts at dealing with clicking jaws and stopping them regressing to a locked joint but can also address issues beyond this point. Through the use of manual therapy and exercises, we are able to treat a wide variety of jaw issues, including a clicking and a locked jaw. By evaluating the biomechanics of the jaw, we will be able to most likely identify the underlying cause and put procedures into place to prevent them from occurring again.

 

Author: Benjamin Sewell


Jaw pain assessed 

Was your Jaw Pain properly assessed?

Traditionally, all pain and restriction in the jaw region, whether it be a clicking jaw, a painful bite, clenching, headaches or even a locked jaw, have all been diagnosed under the one umbrella term, “TMJ”  

The TMJ acronym actually stands for Temporo-Mandibular Joint, the anatomical name of the joint, so to diagnose “TMJ” is similar to you going to the GP after tripping and falling and hurting your lower leg and your GP assessing you and diagnosing you with “Ankle.” It’s merely naming the structure you injured, so a more correct umbrella term should be “Temporo-Mandibular Dysfunction (TMD)”

Incorporated in this umbrella term, there are 4 major muscles groups, 3 different ligaments, 2 joint surfaces, and an articular disc that can all be the cause of TMD, not to mention the trigeminal nerve. Management of an arthritic joint surface is vastly different from managing a spasming muscle, though their initial presentation can be very similar, meaning the ability to accurately diagnose which of these structures are actually causing the dysfunction/pain, determines the correct course of treatment to resolve the symptoms.  There is no “one size fits all” treatment approach to TMJ management

More importantly, accurate diagnosis will provide clinical evidence as to why and how the structure(s) have become involved, so treatment can be tailored to include medium and long term goals to ensure your problem doesn’t return as soon as you finish treatment.  

Consider the advice you may have already been given about your “TMD.”  

·       What was the actual diagnosis? 

·       Did you practitioner diagnose you from your description alone without actually assessing you manually?

·       What assessment techniques (if any) were used to derive that diagnosis? 

·       What were your treatment goals set after assessment?  

·       How were these goals reassessed?

·       What was the clinical reasoning behind the treatment that you may already have gone through?  

·       Did it work?

Most failed treatment occurs because of inappropriate treatment choices due to inaccurate or lazy diagnosis. Just because treatment has failed in the past doesn’t mean you are unfixable, it means you need a better assessment and an appropriate treatment plan.  There is no guesswork in treating “TMD”

 

Author: Nigel Smith


normal TMJ

TMJ normal

The original authors of this Video (unknown) did an amazing job of illustrating normal TMJ rotation and translation. 

 

1) Jaw Resting Position. 

Although the round condyle looks like a perfect fit in the articular fossa, the resting position (dictated by the disc and the length of the ligaments) has the jaw sitting in line with the peak of the articular eminence, meaning the jaw always slides forwards/backwards, rather than ascending/descending out of the fossa.  

Look at the middle of the condyle as the jaw opens. It only moves in the horizontal plane, there is no vertical plane of movement. Compare this to the resting position in the Anteriorly displaced disc with reduction video. 

2) Compartmentalised Movement 

The initial movement is pure rotation of the condyle of the jaw on the disc, or movement in the inferior compartment of the joint. As the condyle moves to its limit of range, the disc and condyle lock and slide forward together creating translation. The translation moment occurs between the disc and the skull, or the superior compartment. Either of these compartments can cause an movement derangement. 

3) Retrodiscal Tissue 

This is the nerve supply and blood supply to an otherwise aneural and avascular joint. The retrodiscal tissue is clear of compression when the disc is sitting in the correct position. As the jaw opens, you can see it stretch but it always remains free of the condyle.  

4) Alveolar Bone Density  

When excessive force is applied to a sphere, the force is transferred to the centre of the sphere and it will break down from the inside out. Look at the quality, colour and density of the alveolar bone in the head of the condyle and the articular eminence and compare it to the Anteriorly displaced disc with reduction video. 

On X-ray, a jaw joint under sustained compression will not necessarily show up as degeneration as you don’t see changes to the joint surface until the alveolar bone has collapsed. 

5) Disc Position 

The articular disc sits on top of the condyle like a beanie and divides the jaw into 2 compartments. It is almost hour-glass or butterfly shaped and throughout the movement the condyle stays in the middle of the bulk of the tissue.

 

Author: Nigel Smith


reciprocal click or anterior disc displacement with reduction

The following video demonstrates anterior disk displacement with reduction.

The following video demonstrates anterior disk displacement with reduction.

Once again, thank you to the original unknown author of this video. 

 

1) Jaw Resting Position 

Compare the resting position of the condylar head, it is sitting backwards and upwards. The ligaments and capsule that cross the joint line have shortened and are creating compression on the disc. The discs response to compression is to displace forward creating a barrier for movement. Overcoming this barrier under compression leads to a clicking sound, and more importantly from a diagnostic point of view, you can clearly see a second reciprocal click on closing as the condyle drops backwards off the disc. The first click is the jaw reducing back into the correct place, the closing click is moving out of place.

2) Compartmentalised Movement

The distinctive roles of the inferior and superior compartments have been lost, the jaw over rotates and compresses the posterior joint capsule before finally overcoming the obstruction.  

3) Retrodiscal Tissue 

When the disc is displaced forward, the retrodiscal tissue can sit across the joint surface and be compressed on basic jaw movements like chewing. This is a common source of pain referring into the ear and pain after function, remembering that the inner workings of the jaw joint are aneural and don’t have the capacity to report pain. 

4) Alveolar Bone Density 

As mention in the normal video, the alveolar bone has become compromised and lost its density and white colour. 

5) Disc Position 

Once the condyle reduces back onto the disc, you can see that even in this severely affected jaw, the condyle can still translate quite a long way forward though in this case, it would be painful as it is weight bearing on the retrodiscal tissue. This is why it is important to assess a clicking jaw that is changing its properties, as these secondary degenerative changes will be occurring without the patient necessarily feeling them.

 

Author: Nigel Smith