Page:Popular Science Monthly Volume 75.djvu/56

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52
THE POPULAR SCIENCE MONTHLY

themselves and their arrangement are the pattern from which the jaw takes its shape. The teeth in different skulls differ so much, that it is extremely difficult, if not impossible, to "match" a missing tooth in one jaw with a tooth from any other one. The natural teeth then have an individuality in keeping with each particular face, and when they are in good condition and in their proper position, can not but add to the beauty, dignity and symmetry of the face. Three people out of four seem to lack in the proper development of the lower part of the face by reason of defective and misplaced teeth, and weak and ill-developed jaws. Hence we see that the "man of destiny," "the man with firm jaw, who knows his own mind," is presumably one who was made to chew properly in childhood, and was not allowed to wash down his food half chewed, or unchewed by gulps of liquid.

PSM V75 D056 Before and after photos of orthodontal jaw treatment.png
Before. After.
 

It is not true, that the teeth must fit into the jaws; the reverse is true, the jaws form themselves around the teeth. The bone grows around the roots of the teeth and forms a socket like the mortar or cement around the bricks in a fire-place. This is easily demonstrated; a tooth, for example, can be completely turned round or moved from one place to another, and, as we say, it grows "fast." For that matter, teeth, as is well known, can be extracted, cleaned and put back again, or teeth from one persons mouth can be put into the place of an extracted tooth in another's mouth and become firmly imbedded and do good service for years. The part of the jaw-bone that embraces the roots of the teeth is called the alveolar process, and it continues to grow and harden for some time after the teeth have been erupted, or after