The etiology of osseous deformities of the head, face, jaws and teeth . ied by this process. The pressure of the contractiletissue upon the crowns of teeth is not sufficient to afiect thealveolar process through the roots of the teeth, but even if itcould modify that spongy structure, its force would stop thereand would not extend to the osseous vault and result in bend- 356 ETIOLOGY OF OSSEOUS DEFORMITIES OF ing it out of shape. In most of these cases the diameter ofthe superior niaxiHa, its alveolar process and teeth, is less thanthat of the inferior maxilla, alveolar process, and teeth. Thi
The etiology of osseous deformities of the head, face, jaws and teeth . ied by this process. The pressure of the contractiletissue upon the crowns of teeth is not sufficient to afiect thealveolar process through the roots of the teeth, but even if itcould modify that spongy structure, its force would stop thereand would not extend to the osseous vault and result in bend- 356 ETIOLOGY OF OSSEOUS DEFORMITIES OF ing it out of shape. In most of these cases the diameter ofthe superior niaxiHa, its alveolar process and teeth, is less thanthat of the inferior maxilla, alveolar process, and teeth. Thisis always the case in the worst forms of irregularities. Insuch cases the muscles and cheek could not press upon theteeth and alveolar process of the upper jaw. The changeswhich take place in the bone are not a bendmg in at one placeand a forcing out at a weaker point to compensate for thespace lost, but are an absorption and deposition of bone atthe point of pressure. And even if such were the case, thestrong pillar of bone situated at the very point of contraction. Fig. 108. of the alveolar process, together ^vith the nasal septum, con-stitute a strong bulwark for resistance to the pressure, whichis suppositiously acting at a distance from the top of the , it would be as impossible to so produce pressure suf-ficient to break the dental arch as it would be for the weightof a building to break the arch of a door or window. Thetongue exerts a much greater force in the act of swallowing,and would prevent inward movement of the teeth if so slighta pressure, as the muscles of the cheeks could exert, were thecause of the deformity. For the sake of the argument, let us suppose it were pos- THE HEAD, FACE, JAWS AND TEETH !57 sible for the buccinator muscle to produce this contraction;we should then expect to find the modification of the osseousstructures uniform. This would shut out semi-V-shaped () and semi-saddle-shaped arches (Fig. 108) entirely, and amajority of
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjecthead, bookyear1894
