Primary Dentition

These are the first teeth to erupt into the oral cavity. The primary dentition is comprised of 20 teeth. Often these teeth are referred to as deciduous teeth. These teeth will be exfoliated (lost) as the permanent teeth erupt. In each arch of the mouth, there are two central incisors, two lateral incisors, two canines, and four molars. The teeth are usually recognized by a letter of the alphabet beginning with “A” (Maxillary right second molar) and ending with “T” (Mandibular left second molar). There are no premolars or third molars in the primary dentition. The approximate eruption and exfoliation dates for the primary teeth are listed in Table 1.

Table 1. Primary Dentition.2
ToothEruption Date
Exfoliation Date
Central Incisor8-12 Months6-7 Years
Lateral Incisor9-13 Months7-8 Years
Canine16-22 Months10-12 Years
1st Molar13-19 Months9-11 Years
2nd Molar25-33 Months10-12 Years
Central Incisor6-10 Months6-7 Years
Lateral Incisor10-16 Months7-8 Years
Canine17-23 Months9-12 Years
1st Molar14-18 Months9-11 Years
2nd Molar22-31 Months10-12 Years
Figure 7. Primary Dentition Teeth Named and Numbered.
primary dentition