Dental eruption : Mnemonic

Primary teeth begin eruption at around 6 months and Permanent teeth at around 6 years. In general, lower tooth erupts before it’s upper counterpart with few exceptions (lower before upper rule). Age of 6-12 years is a period of mixed dentition (eruption of permanent 1st molar to eruption of 2nd permanent molar).

Primary (Temporary Teeth)

primary dental eruption

Rules and Exceptions:

  1. Eruption progresses from medial to lateral except canines which erupt between 1st and 2nd molar.
  2. Incisors erupt in clockwise fashion at a difference of 2 months starting from lower central incisor.
  3. Lower and upper canines and molar at around similar time.
  4. 2-4-6 rule for canines and molars.


  1. Lower central incisor: 6 months
  2. Upper central incisor: 8 months
  3. Upper lateral incisor: 10 months
  4. Lower lateral incisor: 12 months
  5. 1st molars: 12 months + 2 = 14 months
  6. Canines: 14 months + 4 = 18 months
  7. 2nd molars: 18 months + 6 = 24 months

Secondary (Permanent) Teeth

permanent teeth eruption

Rules and Exceptions:

  1. Sequence: Mama Is In Pain, Papa Can Make Medicine, i.e. 1st molar, 1st Incisor, 2nd Incisor, 1st Premolar, 2nd Premolar, Canine, 2nd Molar, 3rd Molar
  2. Eruption occurs sequentially at a difference of 1 year except the 3rd molar which erupts between 18-24 years.
  3. Lower teeth appears few months earlier with exception of the lower canines which erupts almost 2 years earlier, i.e. 9 years.
  4. Premolars appear earlier in upper jaw, i.e. lower 1st premolar would appear at 10 years and lower 2nd premolar would appear at 11 years.
  5. Add 3 years to the age of eruption for the age of completion of calcification.


  1. 1st molar: 6 years
  2. 1st incisor: 7 years
  3. 2nd incisor: 8 years
  4. 1st premolar: 9 years
  5. 2nd premolar: 10 years
  6. canine: 11 years
  7. 2nd molar: 12 years
  8. 3rd molar: 18-24 years

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