by Dr Patrick Grossmann BDS, LDS.RCS,
D.Orth.RCS Wimpole Street, London
Founder member of the Britsh Society for Study of Craniomandibular Disorders
TMD is defined as ‘a group of musculoskeletal conditions involving the temporomandibular joints, masticatory muscles and all associated tissues’; an area of medicine and dentistry which is all too often overlooked is the association between TMD and head, neck and facial pain. The reasons for this are unclear but I am of the opinion that too little attention is given to this subject at undergraduate level and moreover there is no formal postgraduate training pathway in the UK for those interested in pursuing a dedicated course in orofacial pain.
The TM joint connects the mandible with the cranium and dysfunction of this articulation can result in a myriad of seemingly unrelated symptoms which straddle the disciplines of medicine, neurology, ENT medicine, physical medicine, dentistry and even psychiatry. It is therefore not surprising that TMD cannot be pigeon-holed into any category, either dental/medical or surgical.
For that reason, it is not uncommon for patients with TMD to consult numerous healthcare professionals, often ten or more, only to be told they just have to ‘learn to live with it’ for the rest of their life.
The major symptoms of TMD include :
- HEAD PAIN – predominantly in the forehead, temples and occipital regions; this occurs in young children as well as adults
- RETRO-ORBITAL PAIN
- VERTIGO / DIZZINESS
- TOOTH PAIN
- NECK PAIN / STIFFNESS
- LIMITED MOUTH OPENING – with clicking, locking and crepitus.
To appreciate the cause and effect of TMD, a brief description of functional joint anatomy and neurology follows:
The TM joint is unique in that both joints have an upper and lower compartment separated by a cartilaginous articular disc. This arrangement allows both rotational and translational movements to occur, but more importantly, they must act synchronously and in harmony with the dentition; any disturbance within the joint(s) and/or dentition can lead to dysfunction and symptoms.
Fortunately, our knowledge has increased to the point where it is clear that in many cases, a patient’s symptoms are caused by dysfunction in the joint/muscle/ tooth complex.
Treatment is directed at eliminating the dysfunction and associated inflammation, relieving muscle pain and restoring the components of the joint to their normal anatomical position. For technical and clinical reasons, such treatment has become the primary responsibility of the dental profession. The diagram below illustrates a healthy and fully functional joint. (Fig a)
The diagram below (Fig b) shows chronic disc displacement referred to as an internal derangement. This is often the result of macro-trauma such as whiplash, sporting accidents, wisdom tooth extraction and anaesthetic intubation.
The effect of DISC DISPLACEMENT leads to neurovascular dysfunction, pain, muscle spasm and within six months many patients report feeling depressed. This sets up a cycle in which feeling tense and uptight increases muscle spasm and increases pain.
HEAD, NECK and FACIAL pain due to TMD is mediated via the trigeminal nerve which has three principal branches, and the auriculo-temporal branch of the mandibular branch innervates the TMJ (Fig.c below).
The complexity of the trigeminal nerve and its numerous connections is illustrated below in (Fig d).
There are numerous connections between all three branches of the nerve in the brainstem as well as connections with C1-C3 spinal nerves, the so-called trigeminocervical complex. GOADSBY,2003 (Current pain and headache reports). The challenge for the clinician therefore is to differentiate between the site and the source of the pain. This can often be made easier by use of diagnostic block injections. Treatment can only be carried out once all the relevant information has been recorded and a diagnosis of internal derangement has been made.
Treatment involves wearing an intra-oral splint (orthotic) designed to correct the condyle/ disc derangement (sometimes requiring a surgical procedure as well). By repositioning the condyles, the surrounding muscles are allowed to return to their resting length thereby reducing muscle spasm and pain. This treatment, known as ‘anterior repositioning appliance therapy’ has been well documented by SIMMONS, GIBBS. (J. Craniomand.Pract 2005)
(Fig e): The splint is worn 24/7 except for cleaning after meals, and functions by unloading the joints, re-creating the lost superior joint space for the displaced disc. In a study by SIMMONS (Jrnl. Craniomand. Pract 2005) of 48 consecutive patients the most common symptom was occipital cephalgia – 94%. Overall, splint treatment resulted in absence or improvement of 95% of symptoms present before treatment.
Many studies have supported that headache is a common complaint of the craniofacial pain patient. In fact it appears that TMD may be responsible for up to 26% of all headache pain; headaches associated with TMD are predominantly tension-type headaches. A study by Magnusson,Carlsson in 1978, Swedish Dent Jnl and another by Andresik, Headache 1979 found recurrent headache to occur in as many as 70% of TMD patients. There is also a high prevalence in children reporting head pain by the age of 15. (J. Oral Rehab. 1975 (Hansson, Nilner) Interestingly, migraine has also been associated with TMD; Tepper et al (2001, Neurologist) published a paper on the patho-physiology of migraine in which they attribute the 3rd division of C.N.V as a possible contributing factor. “In a large percentage of migraine sufferers, the motor root ……is hyperactive”. The result is excessive jaw muscle activity during sleep with noxious information going back to the sensory nucleus, sensitising it and making the patient more susceptible to migraine attacks. In addition, whenever there is inflammation within the TMJ, vaso-active substances such as substance P are released into the regional blood supply; this substance is elevated in the CNS blood supply in many types of vascular headaches.
The above outlines the conservative approach to TMD; there are, of course some cases which, due to their complexity, do not respond, and the operator has to consider referring the patient for joint surgery to fully address the dysfunction more directly. It has been established that this kind of surgery has a much higher success rate when it is combined with a pre-operative splint (to open up the joint space) as well as a post-operative splint (to support and protect the healing tissues).
I believe that the time has come for us to welcome any opportunity of forging closer ties with our medical colleagues.
IF YOU WISH TO LEARN MORE ABOUT THIS INCREASINGLY IMPORTANT ASPECT OF DENTISTRY, THE BSSCMD OPERATE A ROADSHOW ON TMD, COMPRISING A MORNING OF PRESENTATIONS FOLLOWED BY AN AFTERNOON OF ‘HANDS-ON’ CONSTRUCTING A SIMPLE SPLINT. PLEASE VISIT THE BSSCMD WEBSITE FOR MORE DETAILS.
THE TMD ONE-DAY ROADSHOW
Presented by members of the BSSCMD (British Society
for the Study of Craniomandibular Disorders)
Morning: A series of short presentations on various aspects of TMD will include aetiology, signs, symptoms and treatment.
Afternoon: A hands-on workshop showing how to make, fit and adjust a simple inter-occlusal splint. Attendees will be asked to bring with them a set of casts of their own teeth and blank suck-down appliance base. Other materials will be supplied by BSSCMD.
Dr Patrick Grossmann, Dr Michael White, Dr Andre Hedger, Dr Helen Jones.
Roadshow fee: £250.00, includes 1 year’s free membership of BSSCMD
(value £100) and a free copy of the Society’s current journal.
For more information email firstname.lastname@example.org