Tooth eruption & comparison

Question 1

By what age should all deciduous teeth have erupted?

Answer 1

by 2.5 - 3 years

Question 2

What is the general rule about deciduous teeth eruption?

Answer 2

Lowers before uppers, except for lateral incisors

Question 3

How long does complete apexogenesis taken after decidious tooth eruption?

Answer 3

around 1.5 years after eruption

Question 4

What is the eruption pattern in deciduous teeth?

Answer 4

1 2 4 3 5

A B D C E

Question 5

When do upper deciduous central incisors erupt?

Answer 5

8-12 months

Question 6

When do upper deciduous lateral incisors erupt?

Answer 6

9-13 months

Question 7

When do upper deciduous canines erupt?

Answer 7

16-22months

Question 8

When do upper deciduous first molars erupt?

Answer 8

13-19months

Question 9

When do upper deciduous second molars erupt?

Answer 9

23-33 months

Question 10

When do lower deciduous central incisors erupt?

Answer 10

6-10 months

Question 11

When do lower deciduous lateral incisors erupt?

Answer 11

10-16 months

Question 12

When do lower deciduous canines erupt?

Answer 12

17-23 months

Question 13

When do lower deciduous first molars erupt?

Answer 13

14-18 months

Question 14

When do lower deciduous second molars erupt?

Answer 14

23-31 months

Question 15

Between what ages is the ‘mixed dentition stage’?

Answer 15

6-11 years

Question 16

What is the general rule for permanent tooth eruption?

Answer 16

Lowers before uppers except 2nd premolars

Question 17

What is the eruption pattern for upper permanent teeth?

Answer 17

6 1 2 4 5 3 7 8

Question 18

What is the eruption pattern for lower permanent teeth?

Answer 18

6 1 2 3 4 5 7 8

Question 19

In permanent teeth, how long after eruption does it take for root formation to complete?

Answer 19

3 years

Question 20

When do upper permanent central incisors erupt?

Answer 20

7-8 years

Question 21

When do upper permanent lateral incisors erupt?

Answer 21

8-9 years

Question 22

When do upper permanent canines erupt?

Answer 22

11-12 years

Question 23

When do upper permanent first premolars erupt?

Answer 23

10-11 years

Question 24

When do upper permanent second premolars erupt?

Answer 24

10-12 years

Question 25

When do upper permanent first molars erupt?

Answer 25

6-7 years

Question 26

When do upper permanent second molars erupt?

Answer 26

12-13 years

Question 27

When do upper permanent third molars erupt?

Answer 27

17-21 years

Question 28

When do lower permanent central incisors erupt?

Answer 28

6-7 years

Question 29

When do lower permanent lateral incisors erupt?

Answer 29

7-8 years

Question 30

When do lower permanent canines erupt?

Answer 30

9-10 years

Question 31

When do lower permanent first premolars erupt?

Answer 31

10-12 years

Question 32

When do lower permanent second premolars erupt?

Answer 32

11-12 years

Question 33

When do lower permanent first molars erupt?

Answer 33

6-7 years

Question 34

When do lower permanent second molars erupt?

Answer 34

11-13 years

Question 35

When do lower permanent thirds molars erupt?

Answer 35

17-21 years

Question 36

How do deciduous crowns differ from the crowns of permanent teeth?

Answer 36

• primary incisors are smaller in root & crown proportions
• primary molars are wider mesiodistally than permanent premolars which replace them
• Primary molar crowns are more bulbous
• primary teeth are usually whiter in colour

Question 37

How do deciduous and permanent teeth differ re: roots?

Answer 37

• primary roots tend to be narrower
• primary molar roots are longer & more slender, they tend to flare apically to allow room inbetween for developing permanent tooth crowns

Question 38

How do deciduous and permanent teeth differ re: pulps?

Answer 38

• Primary dentition have relatively large pulp chambers

- pulp horns of primary dentition extend high occlusally - hence pulpal exposure more likely

Question 39

How do deciduous and permanent root canals differ?

Answer 39

• Primary root canals tend to be ribbon shaped

- primary root canals are clinically impossible to clean completely

Question 40

How do deciduous and permanent hard tissues differ?

Answer 40

• coronal dentine is much thinner than permanent

- primary enamel is relatively thin and has a consistent depth

Question 41

How do deciduous and permanent occlusions differ?

Answer 41

• anterior spacing is desired (= no crowdin in permanent dentition)
• deciduous incisors are upright, permanent incisors are proclined, leading to an increase in A-P archlength

Question 42

What is leeway space in deciduous teeth?

Answer 42

Extra space mesio-distal space occupied by primary molars, wider than the replacing permanent pre-molars

• usually equates to 1.5mm eather side in upper arch, 2.5mm lower arch