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Growing from the upper and lower jaws, a child's first set (20
teeth) cut between the ages of about 6 months and 3 years.
The second set appearing at around 6 years. By the age of
around 24, there should be about 32 permanent teeth present in
the human mouth.
Divided by shape and function into four categories: eight
incisors - responsible for 'cutting' food; four canines - for
'tearing' food; eight premolars - for 'crushing' food and twelve
molars - responsible for 'grinding food. Each tooth consists of
a root, which is embedded in the jaw bone and a crown, which is
the part visible on the outer gum line. The solid portion of the
tooth consists of, enamel, dentine and cement. Each tooth also
has a cavity filled with pulp, richly supplied with blood
vessels and nerves that enter the cavity through a small opening
at the base of each root.
Enamel:
Tooth enamel is a hard, resistant substance, which covers the
exposed part of the tooth.
Dentine:
Not quite as hard as enamel, dentine forms the underlying part
of the tooth, from the crown to the root. Composed of cells
called odontoblasts, dentine can repair itself to some extent.
Cement:
Closely resembling that of bone, cement covers the roots of the
teeth. Consisting of a good supply of nerves, its purpose is to
anchor the tooth end of the fibres which join the tooth to the
surrounding bone.
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