MCQs

Question 1

Components of an ideal occlusion

Answer 1

ASMIRC
Angulation of the tooth (roots tipped distal)
Flat curve of Spee
Molar relationship class I
Correct Inclination of the tooth (buccolingual)
No Rotations
Tight Contacts

Question 2

Problems with early XLA of 6

Answer 2

1. Lower 7 may tilt mesially
2. Lower 7 may rotate mesiolingually
3. Lower 7 may lean lingually
4. Over-eruption of upper 6, stopping mesial movement of lower 7
5. Compromises anchorage in the upper arch
6. Provides little space anteriorly for the relief of crowding

Question 3

Best time to extract upper first molars

Answer 3

9 years 4 months

Question 4

Extracting 6s if class II div 1

Answer 4

Extract early then

• correct class II with functional appliance OR
• maintain and incorporate into ortho tx

Question 5

Leeway space principles

Answer 5

Amount by which the space occupied by the primary canine and first and second primary molars exceeds that occupied by the canine and premolar teeth of the secondary dentition, usually averaging 1.5 mm (maxillary) and 2.5mm (mandibular) on each side of the dental arch

Question 6

IOTN and treatment for unilateral posterior crossbite

Answer 6

IOTN score depends on discrepancy between RCP and ICP
-2c: up to 1mm 
-3c: 1.1-2mm
-4c: greater than 2mm
Treat with removable appliance

Question 7

When are removable appliances indicated?

Answer 7

E class thrEEEEE
Xbite: anterior
Posterior crossbite with associated...?
Overbite correction
Space maintainer
Expansion 
Dissipation of molars

Question 8

Skeletal effects of functional appliances

Answer 8

30%

Question 9

Reasons for impacted canine and treatment methods

Answer 9

Associated with missing or diminutive lateral incisors
Familial
Long eruption path
Guidance theory: lateral would usually guide the canine down
Crowding: chronology of eruption
Narrow upper arch
Lack of resorption of primary tooth
Follicular disruption (rare)
TREATMENT:
-leave
-extract
-orthodontic alignment : open or closed exposure
-transplant

Question 10

A patient needs to have the springiness of their arch wire increased eight-fold. How will you do this? Note-the arch wire is composed of a Nickel Titanium alloy.

a. Increase the diameter of the arch wire four fold.
b. Switch to an austenitic Stainless Steel arch wire of the same diameter and length.
c. Reduce the diameter of the arch wire two fold.
d. Increase the length of the arch wire two fold

Answer 10

D - increase the length of the arch wire two fold

Question 11

Digit vs dummy sucking

Answer 11

OB more negatively influenced by dummy sucking
OJ less likely to be increased by dummy sucking
Posterior Xbite more likely to be caused by dummy sucking
Dummy sucking usually stops earlier than digit so has less detrimental effect on permanent dentition

Question 12

Explain 3 methods to prevent habit

Answer 12

Hay Wire appliance
Psychological management
Aversive taste management