Occlusion

Introduction

In his book ‘Eminence’, Morris West wrote that ‘ suppression of debate is an untenable position in today’s world’. Yet that is precisely the position taken by those advocates of the stress theory of temporomandibular dysfunction syndrome (TMJDS). Their position is predicated on the papers of Harris & Feinman, a Consultant Oral surgeon and a Consultant Psychiatrist, which date back to the late 1970’s, who developed their stress is the cause opinion without any examination of the occlusion in their test groups. In the UK at least, this is the prevailing indoctrinated position of many of the participants in the over 50 courses I have given on occlusion. My first observation is that patients who have undiagnosed pain are inevitably ‘stressed’ by both diagnostic and therapeutic failure.

When I give my courses, one of my early questions to the participants is ‘what causes TMJDS pain’. The universal answer is ‘stress’. My next challenge for those who believe in the stress theory is to ask them to explain how the patho-physiological mechanism by which stress, which could affect the body as a whole, causes a unilateral pain. They cannot, and I challenge anyone to provide a coherent explanation for this. Answers such as ‘well it just is’, have no evidence base to support them, and are designed to suppress debate.

For those who believe in the stress theory, they might like to consider the relationship between the following doctors, Billroth, Polya and Marshall. The first two were distinguished surgeons who devised gastric operations to reduce acid secretions on the grounds that stress increased acid production which caused gastric ulceration. Marshall, in contrast showed that the real cause was an infection due to Helicobacter pylori. For this discovery, Marshall was widely vilified by the medical establishment for challenging perceived wisdom. Fortunately he is correct, and is now a Nobel Laureate for his work.

I am firmly of the opinion that it is all too easy to claim that stress is the cause of many medical problems, because this places the ‘cure’ in the patients’ hands, when the real reason is we are not really sure of the pathogenesis. The best explanation of stress as the cause of TMJDS came from a GDP colleague attending one of my occlusion courses. His argument went like this:

‘If I diagnose an occlusal cause, then on the NHS I have to treat the patient. I was not taught much about occlusion as an undergraduate, not sure what to do, and the NHS does not pay me properly for my time. If I tell the patient it is due to stress, then it’s their fault and up to them to sort out the problem’.

With this lack of understanding and poor teaching for too many colleagues in mind, I have always started my courses with a questionnaire, to establish a baseline of who knows what, to ensure that we speak the same technical language as UK terminology is at variance with terms used in the rest of the world, and to act as a reminder. I strongly favour US terminology as it does what it says on the packet, not least because the best dental book I have ever read is Peter Dawson’s seminal work ‘Occlusion’.

But first what is the real cause of TMJDS pain? Eventually, after further prompting about pain causation, the correct group answer emerges. The pain is due to muscle spasm, and like all muscle cramps can vary in both intensity and duration. This opens up the real question, why do the muscles of mastication go in spasm on some patients and not others?

I believe that if we are to understand the pathogenesis of TMJDS, then we need to revisit the basic sciences of anatomy, embryology, physiology, biochemistry and dental treatment and their role in its causation. Specifically, complete denture making gives us further clues. More later, but first, my questionnaire.