Congenital Defects

Question 1

What are the two factors that can contribute to congenital defects?

Answer 1

Genetic Factors

Environmental Factors

Question 2

What is an example of an environmental factor?

Answer 2

Teratogen

Question 3

In order for a teratogen to cause a congenital defect what must happen?

Answer 3

It has to be introduced during specific times of development.

Question 4

True or False; a teratogen is introduced during the 5th week of development, this can cause a congenital defect in the tongue.

Answer 4

True, the stage of development for the tongue is from the 4th to 8th week. If a teratogen is introduced in that time frame it could potentially cause a congenital defect.

Question 5

Clefts account for what percentage of congenital malformations at birth?

Answer 5

15%

Question 6

What are the #1 and #2 congenital malformations at birth?

Answer 6

#1 Cardiovascular
#2 Clefts

Question 7

How does an oblique facial cleft occur?

Answer 7

Failure to fuse the maxillary process and lateral nasal process.

Question 8

How would you describe an oblique facial cleft?

Answer 8

There would be a gap from the corner of the mouth out to the ear.

Question 9

How does a median cleft lip occur?

Answer 9

Failure to fuse the median nasal processes.

Question 10

How does a bilateral cleft lip occur?

Answer 10

Failure to fuse maxillary and medial nasal processes.

Question 11

What two deficiencies are associated with clefts? (Main causes of facial clefts.

Answer 11

• Failure of neural crest cells to develop.

- Failure of mesenchyme to proliferate.

Question 12

What happens if the mesenchyme doesn’t proliferate?

Answer 12

It won’t close the gap between processes.

Question 13

What happens if the neural crest cells come in at the proper place and time?

Answer 13

Development proceeds correctly.

Question 14

True or false; primary palate clefts can be isolated or include clefts of the secondary palates.

Answer 14

True

Question 15

True of false; the failure of shelves to contact is an example of an isolate palatal cleft.

Answer 15

True

Question 16

True of false; the failure of fusion of shelves because the epithelium is not resorbed is an example of a unilateral primary cleft palate.

Answer 16

False; this is an isolated palatal cleft

Question 17

Rupture of the structure after fusion or Defective merging/consolidation of mesenchyme are examples of what type of cleft?

Answer 17

Isolated Palatal Cleft

Question 18

What two types of Clefts have dental influence?

Answer 18

Unilateral primary palatal cleft

Bilateral primary cleft palate

Question 19

What teeth are effected by a unilateral primary palatal cleft?

Answer 19

Effects the incisors (depends which said the cleft occurs)

Question 20

What teeth are effected by a bilateral primary cleft palate?

Answer 20

6-#11 canine to canine

Question 21

What do you often see with palatal clefts?

Answer 21

Lip clefts

Question 22

What causes a cleft tongue?

Answer 22

The lingual swellings and tuberculum impar fail to merge together.

Question 23

What results with a partial tongue cleft?

Answer 23

Deep groove in the tongue which is mostly a hygiene issue.

Question 24

Why does cleft tongue occur?

Answer 24

Failure of epithelial cells to die or mesenchymal cells to proliferate.

Question 25

Why does Treacher-Collins Syndrome occur?

Answer 25

Failure of neural crest cells to migrate to the facial region.

Question 26

What is a common feature of a patient with Treacher-Collins Syndrome?

Answer 26

Sagging eyes that pull laterally.

Question 27

What directs things to happen in a specific way?

Answer 27

Neural Crest Cells