Jim Beyer, age 11, of Lansing, Michigan, for his question:
Where does a new tooth come from?
When we fully understand how the body builds and maintains its teeth, we also know how we can help or hinder the miraculous operation. Most people are glad to cooperate because they desire healthy and durable teeth. It is nice to know that we really can help to avoid cavities and other dental problems. When we know what to do and follow through, there is less work for the dentists to do.
Let's face it, daily brushing can be a bore, especially when we get a quota of cavi¬ties in any case. However, that dreary chore can become an interesting project with worthwhile results. The secret lies in knowing the bows and whys behind the scenes. Teeth are created by buds of very special cell tissue. These buds produce a baby set for temporary use. Later they build a permanent set intended to last a lifetime. The quality of these permanent teeth depends largely on the material available to build them. The job of building them takes from 6 to 14 years which gives us plenty of time to supply the best ingredients possible.
As usual, the miraculous body plans way ahead. The centers for future tooth building are established in the jaws of the unborn baby. Tooth bands develop around the embryo jaws. Thickened wads form along these bands and become tooth buds before the baby is born.
Each bud is a complex wad of cells with different duties. The upper level constructs the crown that pokes above the gum. Other cells in lower levels of the bud build the roots and other structures of the tooth. The crown is completed first and the roots form after the crown erupts through the gums. The building materials are extracted, molecule by molecule, from ingredients in the blood stream and body fluids. The work is done layer by patient layer.
The primary teeth are completed during the first two years of life. Later, their root material is absorbed and the crowns fall out. Meantime, the buds are building the crowns of permanent teeth. Later they add the roots. The main tooth building material is calcium phosphate. Calcium carbonate, magnesium phosphate and calcium fluoride are used in smaller amounts, plus traces of many other materials provided by a well rounded menu. The patient buds do their best to build these teeth, for they cannot produce a third set to replace them.
It stands to reason that permanent teeth are shoddy when only shoddy materials are available to build them. Such teeth are prone to decay and neither brushing nor checkups can do much to save them. However, they are built slowly and you can provide this basic dental assistance through grade school and high school. The secret, of course, is a balanced diet with plenty of milk and other calcium rich items. Sugary snacks tend to hinder the project but neatly spaced regular meals contribute to its success. When you know what goes on behind the scenes, daily brushing makes good sense. Yesterday's food particles encourage decay bacteria and who wants to risk harming those well built perma¬nent teeth?