Teeth eruption occurs in two phases in humans

  1. Temporary teeth eruption and
  2. Permanent teeth eruption


Why do I need to remember the time of dentition?

  1. To assess the growth of a child – this is particularly important in determining the presence of any malnutrition or disease inhibiting normal growth of teeth
  2. To estimate the average age of the child in case other better methods are unavailable.
Image - Temporary Incisor and Canine
Temporary incisor and canine teeth are visible

Points to note in this mnemonic

  1. All the times are approximate. So take a +/- 2 value for the range
  2. Note the time for temporary is in months and for permanent is in years
  3. Where no specific side is mentioned with the name of the teeth the eruption occurs at the same approximate time. For example – by telling “Canine = 18” we mean canine teeth of both sides and the upper and lower jaw erupt almost at the same time, i.e. 18 months.


Temporary or primary teeth or deciduous teeth

Image - deciduous teeth
Deciduous Teeth

All in months
Lower central incisor = 6
Upper central incisor = 7
Upper lateral incisor = 8
Lower lateral incisor = 9
First molar = 10
Canine = 18
Second molar = 24

Permanent teeth

All in years
First molar = 6
Central incisor = 7
Lateral incisor = 8
First premolar = 9
Second premolar = 10
Canine = 11
Second molar = 12
Third molar = 17 to 25

Additional points

  1. Age estimation from dentition is not very accurate method though it is one of the most easily practicable methods in Pediatrics, Forensics, and other specialties. So always try to corroborate the finding with the estimated age from some other method.
  2. A better method of age estimation (when the date of birth is unavailable) is from ossification centers by doing a skiagram.
  3. Note that the places in jaws occupied by the temporary molar teeth are later taken by permanent pre-molar teeth.


Here is an info-graphic for easy remembering of the times of teeth eruption.

Image - Info-graphic for tooth eruption


Arnab Mukherjee

LinkedIn Account


Image Attribution

Infographic – By Arnab Mukherjee.



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