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Why do we have baby teeth?

My six-year-old daughter's first tooth came out last month and others are now wiggly. Lately, she been after me to help get them out, but I've been forbidden by my more prudent half from applying any Rube Goldbergish contraptions to speed up the removal of our daughter's wigglies. Still, this got me wondering about the point of baby or deciduous or milk teeth.

Starter Set

Humans have twenty baby teeth and thirty-two permanent teeth. Your own toothage may vary. Most mammals also have two sets of teeth. Dogs and cats, for example, get their baby teeth in a few weeks and then lose them in a few months (I don't know what that is in dog or cat years).

Seen One, Seen Them All

Most other vertebrates, i.e., fishes and reptiles, have teeth that come and go on an incoming and ongoing basis. This is a boon to all those tropical trinket tourist traps that sell necklaces with shark teeth. A given fish or reptile has a set of teeth that are pretty much all the same.

All About the Fit

Mammals, however, usually have different kinds of specialized teeth that need to fit together properly to work well. The arrangement follows a species specific dental formula. Seems the jaws of the young are too small to accommodate all the permanent ones. The permanent ones are keepers because they probably require a lot of energy to produce. The exceptions seem to prove the rule.

Teeth and Consequences

Baleen whales have baleen instead of teeth. Yet they have tooth buds as embryos, even though they do not form into teeth. Dolphins and other toothed whales have teeth that are all the same and only have one set of teeth.

Hard Wear

Some mammals are particularly hard on their teeth. Elephants, for example, chew lots of tough plant material. They go through six sets of molars. If an African elephant lives longer than its last set of molars, it may die of starvation. I suspect they probably die of other causes first. But I wear a night guard anyway.

Teeth that Never End

Rodents handle the problem of wearing down teeth with continually growing ones. Beavers, for example, have self sharpening incisors for gnawing down trees. The babies (called kits) are born with chompers from the get go.

Handling the Tooth

Then you have the human parents who are pulling out their kids' baby teeth early. I don't know if the tooth fairy is involved, but apparently if the teeth still have the blood supply, they are a source of stem cells, which can be a potential salvation against diseases when they are older. It kind of creeps me out. What about you?