Clinical development of the dentition

Question 1

What are the stages of development?

Answer 1

newborn, deciduous dentition, mixed dentition, permanent dentition

Question 2

What structures do newborns have in place of teeth?

Answer 2

Gum pads

Question 3

What are the shapes of the gum pads in newborns?

Answer 3

Upper is rounded while the lower is U-shaped

Question 4

What is the typical bite of a newborn?

Answer 4

Anterior open bite (skeletal class 2)

Question 5

What do skeletal classes 1/2/3 describe?

Answer 5

The antero-posterior (AP) jaw relationship

Question 6

What is a skeletal class 1?

Answer 6

the mandible is 2-3 mm posterior to the maxilla

Question 7

What is skeletal class 2?

Answer 7

Mandible is retruded relative to the maxilla

Question 8

What is skeletal class 3?

Answer 8

The mandible is protruded relative to the maxilla

Question 9

What are natal teeth?

Answer 9

Teeth present at birth or erupt soon after that are unrelated to the deciduous dentition (separate series)

Question 10

Example of one of the most serious dental developmental disorders?

Answer 10

cleft lip and palate (can be unilateral or bilateral cleft)

Question 11

Signs that someone was born with a cleft lip and palate?

Answer 11

Scar in palate, narrow maxilla, rotated teeth, primary retained teeth, absence of maxillary lateral incisors

Question 12

What time period does the deciduous dentition usually erupt withing?

Answer 12

6 months - 3 years

Question 13

Do the upper or lower deciduous dentition erupt first?

Answer 13

Lowers erupt before uppers

Question 14

In which order do the deciduous teeth erupt?

Answer 14

a (1), b (2), d (4), c (3), e (5) - first primary molar erupts before canine as canine has a longer path of eruption

Question 15

When do the As / 1s / central incisors erupt?

Answer 15

6-7 months

Question 16

When do the Bs / 2s / lateral incisors erupt?

Answer 16

7-8 months

Question 17

When do the Cs / 3s / canines erupt?

Answer 17

18-20 months

Question 18

When do the Ds / 4s / first molars erupt?

Answer 18

12-15 months

Question 19

when do the Es / 5s / second molars erupt?

Answer 19

24-36 months

Question 20

Difference between deciduous and primary dentition

Answer 20

Deciduous incisors more upright/flatter than permanent incisors, deciduous dentition more spaced, deciduous dentition has softer enamel

Question 21

Why are deciduous teeth often worn towards the end?

Answer 21

Primary enamel is softer than secondary enamel. Therefore, with hypodontia, deciduous teeth won’t last in place of missing permanent teeth.

Question 22

Why is spacing in the deciduous dentition important?

Answer 22

To prevent crowding in permanent dentition

Question 23

Chance of crowding in permanent dentition if there is no spacing in deciduous dentition

Answer 23

66%

Question 24

Chance of crowding in permanent dentition if there is <3mm total space in deciduous dentition

Answer 24

50%

Question 25

Chance of crowding in permanent dentition if there is 3-6mm spacing in deciduous dentition

Answer 25

20%

Question 26

How much spacing in the deciduous dentition is preferrable to ensure no chance of crowding in permanent dentition?

Answer 26

>6mm

Question 27

At what ages is there a mixed dentition?

Answer 27

Approx 6-13

Question 28

Which teeth erupt ages 6-8.5?

Answer 28

incisors and 6s (first permanent molars)

Question 29

Which teeth erupt ages 10-12.5?

Answer 29

canines (3s), premolars (4, 5s) and second molars (7s)

Question 30

How does the FDI notation work for deciduous teeth?

Answer 30

Quadrant number (5, 6, 7, 8) + tooth number

Question 31

Which teeth erupt first at age 6?

Answer 31

31, 41 (lower central incisors) and 16, 26, 36, 46 (first permanent molars)

Question 32

Which teeth erupt age 7?

Answer 32

11, 21 (upper centrals), 32, 42 (lower laterals)

Question 33

Which teeth erupt age 8?

Answer 33

12, 22 (upper laterals)

Question 34

Which teeth erupt age 11?

Answer 34

33, 43 (lower canines), 34, 44, 14, 24 (first premolars)

Question 35

Which teeth erupt age 12?

Answer 35

13, 23 (upper canines), 15, 25, 35, 45 (second premolars) 17, 27, 37, 47 (second molars)

Question 36

How is the increased space required for permanent incisors accommodated for?

Answer 36

Spacing of deciduous teeth, increase in inter-canine width, more proclined path of eruption of incisors.

Question 37

What is the inter-canine width?

Answer 37

linear distance between cusp tips of canines in both mandible and maxilla

Question 38

By how much does the inter-canine width increase by in the maxilla to accommodate the permanent incisors?

Answer 38

3.5 mm in maxilla

Question 39

By how much does the inter-canine width increase by in the mandible to accommodate the permanent incisors?

Answer 39

3.0 mm in mandible

Question 40

How does the AP arch length increase to accommodate for permanent incisors?

Answer 40

The permanent incisors are more proclined compared to the upright primary incisors.

Question 41

What abnormalities during tooth eruption would require investigation?

Answer 41

Abnormal eruption sequence or a delay of more than 6 months between the eruption of a L and R tooth (asymmetrical eruption)

Question 42

Possible cause of delayed eruption of teeth

Answer 42

supernumerary teeth may be present which are blocking the path of eruption of the permanent teeth. Surgical extraction of supernumerary teeth required.

Question 43

Name of condition in which a tooth is abnormally large

Answer 43

macrodontia

Question 44

Possible causes of macrodontia

Answer 44

splitting of 1 tooth germ into 2, or fusion of 2 tooth germs (may have 2 pulp chambers and be difficult to slim down)

Question 45

What is hypodontia?

Answer 45

Congenital absence of one or more teeth