Primary and Permanent Dentition Eruption Sequences

Primary Dentition Eruption Sequence
The primary dentition starts to erupt at around 6 months of age, beginning with the mandibular central incisors and ending with the eruption of the maxillary second primary molars between 25-33 months (2-2.75 years).6 Table 1 outlines the eruption sequence for the primary dentition.6 The primary dentition consists of 20 teeth including 4 central incisors (E, F, O, P), 4 lateral incisors (D, G, N, Q), 4 canines (C, H, M, R), 4 first molars (B, I, L, S), and 4 second molars (A, J, K, T) distributed equally between the two dental arches (Figures 9‑10).

Table 1. Primary Dentition Eruption.6
Tooth Type Months
Mandibular Centrals 6-10
Maxillary Centrals 8-12
Maxillary Laterals 9-13
Mandibular Laterals 10-16
Maxillary First Molars 13-19
Mandibular First Molars 14-18
Maxillary Canines 16-22
Mandibular Canines 17-23
Mandibular Second Molars 23-31
Maxillary Second Molars 25-33
Figure 9.
Radiograph (Periapical) of primary mandibular anterior teeth
Periapical radiograph of primary mandibular anterior teeth.
Figure 10.
Radiograph (Bitewing) of primary posterior teeth
Bitewing radiograph of primary posterior teeth.

The mixed dentition is composed of a combination of primary and permanent teeth (Figure 11). As the child matures, the primary teeth begin to exfoliate and are replaced by the permanent dentition. The mandibular central incisors and the first molars are the first to erupt, replacing their primary predecessors while the third molar teeth are the last to erupt in the late teen to early adult years.6 The permanent dentition consists of 32 teeth including 4 central incisors (8, 9, 24, 25), 4 lateral incisors (7, 10, 23, 26), 4 canines (6, 11, 22, 27), 4 first premolars (5, 12, 21, 28), 4 second premolars (4, 13, 20, 29), 4 first molars (3, 14, 19, 30), 4 second molars (2, 15, 18, 31), and 4 third molars (1, 16, 17, 32) distributed uniformly between the maxilla and mandible. The primary first and second molars are replaced by the premolar teeth and the permanent molar teeth erupt posterior to the primary molars. Table 2 outlines the eruption sequence of the permanent dentition.6

Figure 11.
Panoramic radiograph of a mixed dentition
Panoramic radiograph of a mixed dentition.

Permanent Dentition Eruption Sequence

Table 2. Permanent Dentition Eruption.6
Tooth Type Years
Mandibular Centrals/
First Molars
Maxillary Centrals/
Mandibular Laterals
Maxillary Laterals 8-9
Mandibular Canines 9-10
Maxillary First Preolars 10-11
Mandibular First Molars/
Maxillary Second Premolars
Maxillary Canines/
Mandibular Second Premolars
Mandibular Second Molars 11-13
Maxillary Second Molars 12-13
Third Molars 17-21