Class III Malocclusion

Question 1

Which of the following best describes a skeletal class III malocclusion?

A. skeletal class III malocclusion can be due to a small maxilla, a large mandible or a combination of both

b.
A skeletal class III malocclusion can be caused by caused by either maxillary hypoplasia and mandibular hypoplasia or both of these in combination.

c.
A Skeletal class III malocclusion is nearly always due to a large mandible.

d.
A skeletal class III malocclusion is caused by a small maxilla

e.
A skeletal class III malocclusion is caused by mandibular prognathism

Answer 1

A - a skeletal class III malocclusion can be due to a small maxilla, a large mandible or a combination of both

Question 2

Before undertaking pre surgical orthodontics with fixed appliances for a class III patient, the patient should be advised that?

a.
Their class III appearance will improve during this phase of treatment

b.
Any existing speech difficulties are likely to improve as the upper incisors procline

c.
Gingival recession is likely to occur labial to the upper incisors

d.
Their class III appearance will worsen during this phase of treatment

e.
Once the negative overjet exceeds 4mm it will not be possible to eat hard foods

Answer 2

D - their class III appearance will worsen during this phase of treatment

Question 3

The incidence of classs III malocclusion in the UK is approximately what?

Answer 3

3-8%

Question 4

Which of the following best describes the typical dental features commmonly presenting in class III malocclusion

a.
Anterior crossbite, retroclined upper incisors, crowded upper arch, well aligned lower arch.

b.
Class III incisors relationship, anterior crossbite, well aligned upper arch, proclined lower incisors.

c.
Class III incisor relationship, proclined upper incisors, crowded upper arch, well aligned lower arch.

d.
Class I incisor relationship, posterior crossbite, proclined upper incisors, crowded upper arch.

e.
Class III incisors relationship, proclined lower incisors, retroclined upper incisors, crowded upper arch.

Answer 4

C- Class III incisor relationship, proclined upper incisors crowded upper arch, well aligned lower arch

Question 5

When treating class III malocclusion in a patient using a fixed rapid maxillary expansion device, the accompanying headgear must be worn for at least how many hours a day?

Answer 5

14 hours a day