Tooth Eruption Dates

Question 1

What are the 3 growth periods?

Answer 1

First growth period (0-6 years)

Second growth period (6-12 years)

Third growth period (12-18)

Question 2

What occurs during the first growth period?

Answer 2

Appearence - 6 months

Complete primary dentisiton - 2.25 years

Question 3

What occurs during the second growth period?

Answer 3

Shedding & Replacement of primary teeth by permanant teeth

Eruption of first permanent molar behind primary molars - 6 years

Eruption of second permanent molar behind first permanent molar - 12 years

Question 4

What occurs during the thrid growth?

Answer 4

Slow growth

Slow expansion of jaw to accommodate the third permanent molar

Question 5

General eruption rules

Answer 5

1) Lower erupt before upper.
2) Front erupt before back.
3) Upper canines erupt late

Question 6

Sequence of tooth eruption in Primary dentition

Answer 6

Deciduous (Primary) Dentition [6 months - 6 years]

• incisors erupt between 6-9 Months
  
  • lower central —> lower lateral incisors and upper central incisors —> Upper lateral incisors
• 1st Primary molars erupts between 1-1.3 years
  
  • Lower first molars —> upper first molars.
• Canines erupt 1.5 years
  
  • Lower canine —> upper canine
• 2nd primary molars erupt between 1.75-2.5 years
  
  • Lower 2nd molar —> upper 2nd molar

Question 7

Sequence of tooth eruption in Mixed dentition

Answer 7

Mixed Dentition [6-12 years]

The eruption of:

• The 1st permanent molar behind the primary molars at the start of this period [6 years]
• The 2nd permanent molar behind that at the end of this period [12 years]

The shedding and replacement of primary teeth by their permanent successor teeth in two stages:

• Incisors being shed from 6 to 8.5 years
• the more posterior teeth are shed later, from 9.25 to 12 years.
• premolars erupt in a predictable manner between 10-12 years
  
  • lower 1st premolar —> upper first and lower 2nd premolar —> Upper 2nd premolar.
• Canines are less predictable, lower from 9.25-10.5 years and upper 10-11.5 years.

Question 8

When is the permenant dentition completed?

Answer 8

completed at 17-21 years by eruptions of third molars

Question 9

Calcification dates

Answer 9

Primary teeth

• 4-6 months in utero from front to back

Permanent teeth

• First molars just before birth
• incisors 3-5 months except upper lateral (1 year)
• Canines 6.5 months (lower) and 9 months (upper)
• Premolars 1.85-2.65 years
• Second molars by 3 years
• third molars by 8 years

Question 10

Root bifurcation dates of lower permanent roots

Answer 10

Lower 1st molar: 4.5 years

lower 2nd molar: 8.5 years

Question 11

Root completion dates

Answer 11

Primary Teeth: 1-1.5 years after eruption

Permanent teeth: Less than 2 years (lower incisors) to more than 3 years (1st molars) after eruption