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Sir, after almost 40 years I continue to be confounded by my professions inability to reconcile the connection between occlusal disease (OD)/temporomandibular disorder (TMD) and occlusion. Having had to actually treat patients with TMD symptoms and/or failing dentitions, in my experience I can unequivocally say that the occlusion is the primary aetiologic factor in the vast majority of cases.
So why such a discrepancy between what some of us do every day, and what the literature' says? I believe part of the problem is understanding the aetiology. OD/TMD is all about muscles protecting teeth. It really isn't more complex than that. A typical example would be a patient who, if positioned properly in centric relation would only have posterior contact and an open bite. Functioning in this position would be comfortable, and this triggers the classic old brainstem-level avoidance reflex such that the muscles of mastication reposition the mandible (at the expense of condylar position) to avoid that trauma.
The challenge is that you cant identify these interferences very easily, because those powerful muscles will work very hard to protect the teeth when you try to manipulate that mandible. You have to deprogramme those muscles first, and that's where (properly adjusted) occlusal splints come in. Without deprogramming, you can't identify the interferences in the first place. I suspect that's where a lot of the 'research' problem lies. Occlusal splint therapy is an art and science in itself and not the easiest thing in the world to do – properly.
In the 1970s and 1980s, treatment was all about equilibration. In hindsight, it was foolish to do invasive treatment on an unstable patient. You need to stabilise them with an occlusal splint first, which is not easy and takes months along with skill and expertise to be effective. Given all these factors, the most refractory patient can stabilise even in the presence of degenerative joint disease. Other very important aspects to occlusion are spinal-cervical connections, restricted envelopes of function, and the critical need to restore anterior tooth length and nociceptive input to avoid lateralised function.
The best restorative and periodontal care will fail with a bad occlusion. If you understand occlusion, you will avoid many things that will get you into trouble in dentistry. And if you do get into trouble, understanding occlusion will generally get you out of it.