Paeds: Developing Mixed Dentition

Question 1

When do permanent teeth first come in?

Answer 1

Age 6

Question 2

When have the primary teeth all erupted by?

Answer 2

Age 3

Question 3

Key differences between primary and permanent teeth (7)

Answer 3

1. Dentin is less mineralised in primary teeth.
2. Lamina dura is thicker in primary teeth.
3. Enamel is thinner in primary teeth
4. Primary teeth are whiter (dentin isn’t mineralised)
5. Bigger pulp cavities
6. Roots more divergent in primary teeth
7. More bulbous

Question 4

Clinical implications: Child with a mixed dentition and the parent is concerned the adult teeth look yellow.

Answer 4

Reassuring the parent that it’s very normal for the permanent teeth to appear more yellow, this is a natural developmental feature.

Question 5

Clinical implications: Primary teeth have a larger pulp to crown ratio than permanent teeth

Answer 5

Important to know this when placing restorations and preparing cavities. Also caries progress occurs much faster (especially in the molars).

Question 6

Clinical implications: more bulbous - larger surface area of contact point.

Answer 6

1. Aproximal caries

Question 7

When would you see the first primary teeth in the mouth?

Answer 7

6 months

Question 8

Which are the first teeth to appear in the mouth?

Answer 8

Lower central incisors (As)

Question 9

When is the primary dentition complete?

Answer 9

2.5 years (30 months)

Question 10

When is the mixed dentition first seen and which teeth is first seen?

Answer 10

6 years old —> lower central incisors (followed by the first molars)

Question 11

What age range do the anterior teeth erupt (aswell as canines and first molars)?

Answer 11

6-8 years old

Question 12

When do the canines and the premolars tend to erupt?

Answer 12

8-11years old

Question 13

Age 9 specific feature in the upper arch to be aware of…

Answer 13

upper canines should be palpable

Question 14

Molar incisor hypomineralisation

Answer 14

Mother systemically unwell or child becomes unwell soon after being born in 3rd trimester.

Affects - 1s, 2s and 6s

Question 15

Primate spacing

Answer 15

Necessary as teeth are bigger and more teeth.

Spaces seen —>
Upper arch: between the B and C

Lower arch: between the C and D

Question 16

Clinical implications: diastema/spacing in child’s teeth —> parent is concerned.

Answer 16

Reassure parent this spacing is normal and allows and maintains space for adult teeth.

Question 17

What habits could cause a child’s face to develop in an abnormal way?

Answer 17

Dummies and thumb-sucking

Question 18

Orofacial dyskinesia

Answer 18

Excessive facial/tongue/oral movements “tics” that mean the face is in a constant state of movement (seen in patients with learning disabilities - this repetitive movements can dictate how the face grows an predispose patients to e.g. overjets).

Question 19

Clinical implications: early loss of primary teeth

Answer 19

Formation of fibrous tissue over the erupting tooth = delayed eruption.

Question 20

Describe features of this DPT

Answer 20

Patient ~ 7yrs
Lower Es have stainless steel crowns on them

Question 21

Patient aged nine comes into the clinic…

Answer 21

3s are they palpable in the labial sulcus
6s are they carious, what’s the prognosis (now would be the best time to extract them)
5s are they there (hypodontia)

Question 22

Angle’s classification

Answer 22

Molar relationships

Question 23

Answer 23

Class II incisor molar relationshop

Question 24

Answer 24

Class I incisor relationship

Question 25

Answer 25

Class III