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 right 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
Tooth Eruption Date
(Avg.)
Exfoliation Date
(Avg.)
Maxillary
Central Incisor 8-12 Months 6-7 Years
Lateral Incisor 9-13 Months 7-8 Years
Canine 16-22 Months 10-12 Years
1st Molar 13-19 Months 9-11 Years
2nd Molar 25-33 Months 10-12 Years
Mandibular
Central Incisor 6-10 Months 6-7 Years
Lateral Incisor 10-16 Months 7-8 Years
Canine 17-23 Months 9-12 Years
1st Molar 14-18 Months 9-11 Years
2nd Molar 22-31 Months 10-12 Years
Figure 7. Primary Dentition Teeth Named and Numbered.
primary dentition