266
UNIT 3
Organ Systems
Figure 14-7.
Overview of the teeth
.
There are two sets of
teeth
that form during a person’s lifetime: the
primary
(
baby
)
teeth
and the
secondary
(
adult
)
teeth
.
The
secondary teeth will eventually replace the primary teeth. The secondary teeth are more commonly called
permanent teeth
by
dentists. There are 32 permanent teeth in an adult. Each of the four quadrants includes two
incisors
, one
canine
, two
premolars
,
and three
molars
in the mandibular and maxillary dental arches (
left
). The tooth is composed of several types of hard tissues:
dentin
,
enamel
,
cementum
, and the
alveolar bone
. The central core of each tooth is a chamber containing
dental pulp
made up of mucous
connective tissue with a rich supply of nerve F
bers and blood vessels. Each tooth has a
crown
,
cervix
, and
root
(see ±ig. 14-1). The
crown of the tooth is covered by enamel, the hardest tissue found in the body; the cervix is the junction between the crown and
root; and the surface of the root is covered by cementum, which connects to the alveolar bone by the
PDL
. The junction between
the enamel and cementum is the
CEJ
, and the border between the dentin and enamel is the
DEJ
.
T. Yang
Incisors
Incisors
Incisors
Canine
Canine
Canine
Canine
Canine
Molars
Molars
Premolars
Premolar
Premolars
Maxillary teeth
Mandibular teeth
Anterior teeth
Anterior teeth
Posterior teeth
Posterior teeth
Enamel
Dentin
DEJ
Neonatal line of enamel
Neonatal line of dentin
Cementoenamel junction
Acellular
cementum
Cellular
cementum
Alveolar bone
(alveolar process)
Apical
foramen
Gingiva
Alveolar
mucosa
Gingival
sulcus
Dental pulp
Dental pulp
Dental pulp
Nerve fibers and
blood vessels
Predentin
Predentin
Predentin
Alveolar
Alveolar
bone
bone
Alveolar
bone
Periodontal
ligament (PDL)
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