Development of the dentition

Question 1

In a newborn, what shape are the upper gum pads?

Answer 1

Rounded

Question 2

In a newborn, what shape are the lower gum pads?

Answer 2

‘U’ shaped.

Question 3

If a child is born with a tooth, what’s this called?

Answer 3

A natal tooth

Question 4

What are the 3 classes of jaw relationship? Explain each class.

Answer 4

Skeletal class 1: Mandible 2-3mm posterior to the maxilla.

Skeletal class 2: Mandible retruded relative to the maxilla.

Skeletal class 3: Mandible protruded relative to the maxilla.

Question 5

What is the order of eruption for deciduous teeth?

Answer 5

a,b,d,c,e.

Question 6

At what age should all of the deciduous teeth have erupted by?

Answer 6

3

Question 7

Is spacing desirable in the deciduous dentition?

Answer 7

Yes

Question 8

At what age is there a mixed dentition?

Answer 8

6-13

Question 9

What are the first permanent teeth to erupt?

Answer 9

Lower 1 or 6.

Question 10

A mixed dentition has 2 stages A and B; Explain what erupts at each stage.

Answer 10

A: 6-8.5
First permanent molars and incisors.

B: 10-12.5
Canines, premolars and second molars.

Question 11

How does the dentition accommodate permanent incisors.

Answer 11

Spacing in the deciduous dentition.

Permanent teeth more proclined.

Question 12

What is the rule about teeth that lie proximally to one another?

Answer 12

The proximal tooth comes in 6 months after the tooth.

Question 13

What is the rule regarding central and lateral incisors?

Answer 13

Central must come before lateral.

Question 14

What are supernumerary teeth?

Answer 14

Extra teeth that come in-between the the deciduous and permeant dentition.

Question 15

List and explain the bite classifications.

Answer 15

Anterior cross bite: Some anterior teeth lie in front of the lower and some lie behind the lower.

Increased overjet: Upper teeth project forwards.

Reversed overjet: Lower teeth lie in front of the upper teeth.

Posterior crossbite: Some upper posterior teeth lie in front of the lower and some lie behind. (mixed)

Question 16

What is the order of eruption for both upper and lower stage B?

Answer 16

Upper: 4,5,3.
Lower: 3,4,5.

Question 17

Where does arch length increase?

Answer 17

Length increases after/Posterior to the first deciduous molar.

Question 18

What is leeway space?

Answer 18

The difference in size between the deciduous and permanent dentition.

Question 19

What is the leeway space of the maxilla?

Answer 19

1.5mm

Question 20

What is the leeway space of the mandible?

Answer 20

2.5mm

Question 21

What is the ideal static occlusion?

Answer 21

Incisors slightly proclined.
Lower incisal edge in contact with upper cingulum.
Overbite 2-4mm.

Question 22

In ideal static occlusion; what are the points of contact for some molars?

Answer 22

Mesiobuccal cusp of upper permanent molars occlude the buccal groove of mandibular first molar.

Question 23

List and explain the 3 incisor classifications.

Answer 23

Class 1: Lower incisal edges occlude the cingulum of the upper incisors.

Class 2 division 1: Lower incisal edges lie posterior to the cingulum.

Class 2 division 2: Upper centrals are retroclined.

Class 3: Lower incisal edges lie anterior to the cingulum of the upper incisors.