malocclusion

Question 1

Other than specific causes, which 3 factors have an influence on malocclusion?

Answer 1

1. Skeletal Influences
2. Soft Tissue Influences
3. Dental Influences

Question 2

What is a teratogen?

Answer 2

Agents capable of causing embryological defects.

Question 3

What are 2 examples of teratogens and what do they cause?

Answer 3

1. Folate Deficiency - causes cleft lip and palate.
2. Alcohol - causes foetal alcohol syndrome.

Question 4

Which 2 events come under skeletal influences?

Answer 4

1. Skeletal growth disturbances.
2. Childhood fractures.

Question 5

Which 3 structures cause soft tissue influences on malocclusion?

Answer 5

1. Lips
2. Tongue
3. Fraenum

Question 6

Describe the difference between competent and incompetent lips.

Answer 6

COMPETENT: oral seal created when swallowing by lips fully closing together.

INCOMPETENT: can only close with excessive muscle activity.

Question 7

One factor causing malocclusion is a primary tongue thrust. What is this and how does it occur?

Answer 7

Associated with excessive circum-oral muscle activity on swallowing creating an anterior open bite.

Question 8

Which soft tissue defect is most likely to cause a midline diastema?

Answer 8

A prominent fraenum.

Question 9

Describe the effect of a thumb sucking habit on occlusion.

Answer 9

1. proclination of the upper incisors.
2. retroclination of the lower incisors.
3. maxillary constriction.
4. crossbite (with/without displacement).
5. anterior open bite which can be asymmetric.