The "deciduous dentition" is the common term used to designate the first set of
a. Temporary Teeth or Primary Teeth. The terms "temporary teeth" or
"primary teeth" are often used because these teeth are replaced by a permanent or
second set early in life. The deciduous teeth are also called "baby" or "milk" teeth. The
first of the deciduous teeth push through the gums (erupt) at an average age of 6
months. All deciduous teeth are usually erupted by the end of the second year.
b. Description of the 20 Deciduous Teeth. There are 20 deciduous teeth, 10
in each jaw. In each half of each jaw, beginning at the midline and extending backward,
these teeth are called: central incisor, lateral incisor, cuspid, first molar, and second
molar. See figure 4-2. The name for each tooth is made more specific by the addition
of terms indicating its location within the mouth, such as maxillary (upper) left central
incisor or mandibular (lower) right cuspid. Thus, there are four of each type of tooth.
Each is individually designated as maxillary or mandibular and as right or left.
c. Permanent Tooth Formation and Temporary Tooth Resorption. During
the period of deciduous dentition, the permanent teeth are in the process of formation
within the jaw. In the course of development, the roots of the temporary teeth undergo
resorption (gradually dissolve) until there is insufficient remaining root structure to
support them. During the period from about 6 to 12 years of age, the temporary teeth
thus loosen and are lost. Temporary teeth are replaced by permanent teeth in a
physiologically controlled sequence.
Figure 4-2. Deciduous teeth.