How it came about

Red Eft asked me to post the history of my mouthguard, and the reason my dentist feels that it is wrongly made. (RE, this may or not be relevant to your story, our mouthguards have the same immediate purpose but different objectives.)

The story starts last autumn, when I began having earaches (as I thought), which became frequent and painful enough that I went to see the doctor. He correctly diagnosed that it wasn't an ear problem as such, and sent me off to the jaw-orthopedics centre of the local hospital.

The clinic doctor said that I had not dislocated the jaw (an easy call: I didn't faint from the pain when he pulled my mouth open) and concluded after x-rays that I had probably torn or dislocated the cartilage pad between jaw and skull on that side. His advice was to wear a mouthguard whenever possible, which would simply prevent me from bringing my teeth together (by getting in the way), which in turn would reduce the stress on the cartilage pad. This is a simple plastic shield which fits tightly onto my lower teeth and projects some 2 to 3 millimeters around them (like a glove around your hand). Wearing it has definitely done me some good: the "earache" symptoms are gone.

Fast forward to last week, when I went to the dentist to have an AWOL filling glued back into place. He declared the mouthguard to be badly designed and improperly fitted, and explained why.

When you close your mouth (with nothing but your tongue in it), both sets of teeth meet: upper molars click against lower molars, eye teeth against eye teeth. That's normal and correct: the pressure of your jaw muscles is divided over twenty teeth (ten to twelve points of contact). No tooth bears too much pressure. This is important, because the jaw muscles generate enough power to crush brick: a person in an epileptic fit can bite off the fingers of someone giving him first aid.

Now, put the blunt end of a pencil in your mouth, so that it rests in the valley of one molar, and close your mouth again. Your teeth no longer meet (obviously). When you tense up your jaw muscles now, all that power is being brought to bear on two teeth: the molars that grip the pencil.

This is exactly where my current mouthguard is allegedly wrong. Because it is an even 2 or 3mm thick, only the last pair of molars actually meet when I close my mouth, my eyeteeth are several millimeters apart. To make it worse, the left side is thicker than the right. When the dentist did the carbon-paper contact test, there was one single black spot: on the last two molars on the left.

The dentist fears that the long-term effects of this extreme pressure imbalance, would turn a one-time acute problem into a long-term chronic condition. He will make me a "proper" mouthguard next month, which will be quite differently fitted. It will be basically wedge-shaped, much thicker at the front than the back, so that all my upper teeth contact it when I close my mouth; and it will also be properly aligned left to right. This has a certain ring of logic to it.

On the other hand, the physiotherapist is treating a problem that presented on the left side of my mouth, by strengthening the muscles on the right side. How logical is that? (I'll save the story of the physio for another time.)

The burning question is, of course, who is right? We the patients are pretty much at the mercy of doctors; when they disagree we have to decide between them, based on ... what exactly? Half-understood ideas, apparent analogies, dubious precedents, an air of trustworthiness, gut feeling?

I know that my dentist is very highly skilled, because other dentists have remarked enviously on the excellent quality of his work. Does being a very good dentist qualify him to talk about orthopedics? Possibly not, but I had to make a choice. I chose to believe him.