Biomedical Engineering Reference
In-Depth Information
A content of fluoride added to either toothpaste or mouthwash
lowers the solubility of calcium orthophosphates (by formation of
FHA on the surface) and therefore improves the acid-resistance of
dental enamel [438, 460-465, 752]. Furthermore, fluorides also
reduce production of acids by bacteria in the mouth by reducing their
ability to metabolize sugars. However, dental treatment by fluorides
must be used with care because an improper treatment results in
formation of CaF
globules deposited on the enamel surface [753].
To conclude the teeth subject, let me briefly mention on the
practical application of teeth. Due to relatively small dimensions
of normal teeth, only tusks and ivory of giant animals are used. For
example, both the Greek and Roman civilizations used large quantities
of ivory to make high value works of art, precious religious objects
and decorative boxes for costly objects. Ivory was often used to form
the whites of the eyes of statues. Prior to introduction of plastics, it
was used for billiard balls, piano keys, buttons and ornamental items.
The examples of modern carved ivory objects are small statuary,
netsukes, jewelry, flatware handles and furniture inlays.
2
1.4.3
Antlers
Deer antlers (Fig. 1.15) are unique biological structures since their
growth rate is without parallel in vertebrates and because they
are the only bony appendages in mammals capable of complete
regeneration. This allows for basic research in bone biology without
the interference of surgical procedures and their adverse effects
in animals where samples are obtained. In addition, antlers also
allow for the gathering of a large amount of samples from different
populations to assess nutritional and ecological effects on bone
composition and structure [754-757]. They are costly sexual
secondary characters of male deer and constitute 1 to 5% of the
body weight [758]. Recent studies suggest that antler regeneration
is a stem cell-based process and that these stem cells are located in
the pedicle periosteum [759, 760].
Antlers are not true horns; they are a simple extension of bone, so
they have a matrix of biological apatite similar to that of mammalian
bones [761]. Antlers are large and complex horn-like appendages of
deer consisting of bony outgrowths from the head with no covering
of keratin as is found in true horns. Usually, they begin growing in
march and reach maturity in August. In winter, antlers fall off; this
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