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Anomalies of Tooth Structure

Course Number: 651

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).7 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.7

Tooth TypeMonths
Mandibular Centrals6-10
Maxillary Centrals8-12
Maxillary Laterals9-13
Mandibular Laterals10-16
Maxillary First Molars13-19
Mandibular First Molars14-18
Maxillary Canines16-22
Mandibular Canines17-23
Mandibular Second Molars23-31
Maxillary Second Molars25-33
Primary and Permanent Dentition Eruption Sequences - Figure 1

Figure 10.

Periapical radiograph of primary mandibular anterior teeth.

Primary and Permanent Dentition Eruption Sequences - Figure 2

Figure 11.

Bitewing radiograph of primary posterior teeth.

The mixed dentition is composed of a combination of primary and permanent teeth (Figure 13). 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.7 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.7

Primary and Permanent Dentition Eruption Sequences - Figure 3

Figure 12. Panoramic radiograph of a mixed dentition.

Permanent Dentition Eruption Sequence

Table 2. Permanent Dentition Eruption.7

Tooth TypeYears
Mandibular Centrals/
First Molars
Maxillary Centrals/
Mandibular Laterals
Maxillary Laterals8-9
Mandibular Canines9-10
Maxillary First Premolars10-11
Mandibular First Premolars/
Maxillary Second Premolars
Maxillary Canines/
Mandibular Second Premolars
Mandibular Second Molars11-13
Maxillary Second Molars12-13
Third Molars17-21