teeth are anchored in each jaw from the midline toward the
sides in the following sequence: central incisor, lateral inci-
sor, canine (cuspid), F
rst molar, and second molar.
The primary teeth are usually shed in the same order they
erupted, after their roots are resorbed. Then, the
push the primary teeth out of their sock-
ets. This secondary set consists of thirty-two teeth—sixteen in
each jaw—and they are arranged from the midline as follows:
central incisor, lateral incisor, canine (cuspid), F
(bicuspid), second premolar (bicuspid), F
rst molar, second
molar, and third molar
(f g. 17.9)
the types and numbers of primary and secondary teeth.
The secondary teeth usually begin to erupt at six years,
but the set may not be completed until the third molars
emerge between seventeen and twenty-F
ve years. Sometimes
these third molars, also called wisdom teeth, become wedged
in abnormal positions in the jaws and fail to erupt. Such
wisdom teeth must be removed to alleviate pain.
The teeth break food into smaller pieces, which begins
mechanical digestion. Chewing increases the surface area
What are the functions of the mouth?
How does the tongue function as part of the digestive system?
What is the role of the soft palate in swallowing?
Where are the tonsils located?
are the hardest structures in the body. They are
not considered part of the skeletal system because they have
at least two types of proteins that are not also found in bone,
and their structure is different.
Teeth develop in sockets in the alveolar processes of the
mandibular and maxillary bones. Teeth are unique structures
in that two sets form during development
rst set, the
(deciduous teeth), usually erupt
through the gums (gingiva) at regular intervals between the
ages of six months and two to four years. The ten primary
Opening of auditory tube
Sagittal section of the mouth, nasal cavity, and pharynx.