Here’s a question that has bugged me since childhood. Why does the tooth fairy collect teeth? Why does she want them so much she’s willing to give a quarter or even a loonie for every one she finds under a pillow?

Teeth, at first glance, don’t seem very valuable. As any encyclopedia will tell you, they’re “calcified structures, attached to the upper and lower jaws of vertebrates and a few lower animals, and used primarily for mastication.” In other words, they’re the little hard things in your mouth you use to chew food.

The visible portion of a tooth, the crown, is covered with enamel, the hardest tissue the body produces. Inside the enamel is the dentin, a bone-like substance attached to the bone of the jaw by the hidden root, which is covered with a hard, thin layer, called cementum. Inside the dentin, the pulp cavity holds blood vessels, nerves and connective tissue, which reach into the jaw through the root canal.

Humans grow two sets of teeth. My six-month-old daughter has just sprouted her first two; eventually she will have 20 “baby teeth” (properly called deciduous teeth). As her jaw grows, the roots of her baby teeth will separate, opening up space for the emergence of her permanent teeth, whose development will cause her jaw tissues to suck up the roots of her baby teeth, causing them to loosen and fall out.

Baby teeth are replaced by 28 permanent teeth, followed, in the late teenage years, by four additional ones, the wisdom teeth (although having had to have two of them pulled, I don’t see much wisdom in them at all). Some people’s wisdom teeth never appear, and they may eventually disappear from human mouths altogether: since modern foods are easy to eat, there’s no survival benefit left in being able to grind coarse grain with your jaw.

Wisdom teeth are among a total of 12 broad, flat grinding teeth at the back of the mouth called molars. In front of them are eight bicuspids (a “cusp” is a point; the bicuspids have two each), then four cuspids (single-pointed teeth, better known as “canines,” because they’re particularly pronounced in dogs), then four lateral incisors and four central incisors. The incisors cut our food, the cuspids and bicuspids tear it into smaller pieces, and the molars grind it into pulp.

Within this basic human mouth design there’s still plenty of room for variation. Not everyone grows the same number of teeth. Although our teeth are designed to fit together neatly when we bite, some people’s teeth are misaligned, leading to problems ranging from sore jaw muscles in the jaw to trouble speaking.

Tooth problems have been of concern since before the dawn of history. Cro-Magnon skulls from 25,000 years ago show evidence of tooth decay, and a Sumerian clay tablet from 5,000 BC discusses toothache (it says it’s caused by small gnawing worms within the tooth).

The most common form of tooth disease is dental caries, better known as “cavities.” Bacteria are constantly at work in the mouth, reacting with carbohydrates to form acids that can dissolve tooth enamel. Once there’s a hole in the enamel, other bacteria can penetrate the dentin, and eventually infection can reach the pulp cavity and, through the root canal, the jaw itself, where a pocket of pus, or “abscess” may form.

Dentists have learned how to clean the decayed material out of cavities and fill them back in (and treat many other tooth problems, equally as unpleasant), allowing people to keep their teeth longer and greatly improving the quality of life of literally millions of human beings, who are almost universally ungrateful and avoid visiting members of the profession if at all possible.

The best way to avoid visiting the dentist for anything other than routine checkups is to brush and floss regularly, which removes the bits of food bacteria feed on and some of the bacteria themselves, and prevents the build-up of plaque (a protective covering the bacteria produce to escape the anti-bacterial effects of saliva) or, worse, tartar, which is hardened plaque mixed in with salivary mucus and food residue.

The addition of fluoride to drinking water, common in many North American cities (though not Regina) has greatly reduced the incidence of cavities, especially in children.

Teeth today are probably in better shape than they have been at any time in history–which means it’s time for the Tooth Fairy to increase her rates.

The improved quality of the merchandise demands it.

Permanent link to this article: https://edwardwillett.com/1995/08/teeth/

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