The Marvels in Your Mouth

Mary Roach in The New York Times:

Dr. Van der Bilt and his colleagues have laid claim to a strange, occasionally repugnant patch of scientific ground. They study the mouth — more specifically, its role as the human food processor. Their findings have opened up new insights into quite a few things that most of us do every day but would rather not think about. The way you chew, for example, is as unique and consistent as the way you walk or fold your shirts. There are fast chewers and slow chewers, long chewers and short chewers, right-chewing people and left-chewing people. Some of us chew straight up and down, and others chew side-to-side, like cows. Your oral processing habits are a physiological fingerprint.

Dr. Van der Bilt studies the neuromuscular elements of chewing. You often hear about the impressive power of the jaw muscles. In terms of pressure per single burst of activity, these are the strongest muscles we have. But it is not the jaw’s power to destroy that fascinates Dr. Van der Bilt; it is its nuanced ability to protect. Think of a peanut between two molars, about to be crushed. At the precise millisecond the nut succumbs, the jaw muscles sense the yielding and reflexively let up. Without that reflex, the molars would continue to hurtle recklessly toward one another, now with no intact nut between. To keep your he-man jaw muscles from smashing your precious teeth, the only set you have, the body evolved an automated braking system faster and more sophisticated than anything on a Lexus. The jaw knows its own strength. The faster and more recklessly you close your mouth, the less force the muscles are willing to apply. Without your giving it a conscious thought. Teeth and jaws are impressive not for their strength but for their sensitivity, Dr. Van der Bilt has found. Chew on this: Human teeth can detect a grain of sand or grit 10 microns in diameter. A micron is 1/25,000 of an inch.

More here.