Orthodontics

Question 1

Overjet (also what is the normal range)

Answer 1

Normal range is 2-4mm.

Overjet is the distance between the maxillary and mandibular incisors in a horizontal plane

Question 2

Overbite

Answer 2

Overbite is the vertical overlap of the upper and lower incisors when viewed anteriorly. One third to one half coverage of the lower incisors is normal

Question 3

Deep Bite Is most commonly associated with which class of malocclusion

Answer 3

Class 2 division 2

Question 4

Leeway space

Answer 4

Difference in mesial-disto diameter between c d e and 3 4 5

Question 5

What is the leeway space in the maxilla and mandible respectively

Answer 5

Maxilla 1-1.5mm
Mandible 2-2.5mm

Question 6

Natal and neonatal teeth

Answer 6

Natal - at birth
Neonatal - within weeks

Both are premature and have weak roots

Question 7

Macrodont

Answer 7

Abnormally large tooth
Can be due to fusion or gemination

Question 8

In which order does the primary dentition erupt in?

Answer 8

A b d c e (it’s abcde but swal the c and d)

Question 9

Difference between primary dentition and permanent dentition

Answer 9

Primary dentition more upright. Has more spaces. Softer enamel than permanent teeth so wears down faster .

Question 10

Order and time of eruption for permanent dentition

Answer 10

First phase: incisors and first molar (6-8.5)

Second phase : second molar and premolars and canines (10-12.5)

Question 11

First tooth to erupt (most commonly )

Answer 11

1st molar

Question 12

Last tooth to erupt (before wisdom tooth erupts at 17-21yo)

Answer 12

2nd molar

Question 13

What is the magnitude of increase in inter canine width to accommodate permanent incisors

Answer 13

3.5mm increase in maxilla
3mm increase in mandible

Question 14

Why is mild crowding Normal in mixed dentition?

Answer 14

Leeway space. The C D E are bigger in mesial distal diameter compare to 3 4 5. When C D E drop, there is space for. 3 4 5 to come in without crowding

Question 15

Anterior crossbite vs posterior crossbite

Answer 15

Upper incisors biting behind lower incisors

Posterior crossbite: posterior mandibular teeth on one side lie anterior to maxillary teeth ( displacement of mandible on closure )

Question 16

There is an increase in inter canine width BUT arch length does NOT increase in front of the first primary molar

Question 17

How does the jaw become longer

Answer 17

There is an increase in arch length ONLY POSTERIOR to the first deciduous molar

Question 18

Ideal static occlusion / ICP

Answer 18

Class 1
Overjet qnd overbite 2-4mm on average

Mesiobuccal cusp of the upper molar occluded with groove of lower molar

Mesial inclination of teeth

Tight proximal contacts

Curve of speed

Lingual inclination of canine to molars

Question 19

Class 1

Answer 19

Lower incisors occlude with the cingulum plateau of the upper central incisors

Question 20

Class 2 div 1

Answer 20

Lover incisor edges lie posterior to the cingulum plateau

Overjet increased, upper central incisors proclined

Question 21

Class 2 division 2

Answer 21

Lower incisors lie posterior to cingulum plateau

Upper incisors retro lined, deep bite

Question 22

Class 3

Answer 22

Lower central incisors lie anterior to cingulum plateau