Congenital Defects Flashcards
What are the two factors that can contribute to congenital defects?
Genetic Factors
Environmental Factors
What is an example of an environmental factor?
Teratogen
In order for a teratogen to cause a congenital defect what must happen?
It has to be introduced during specific times of development.
True or False; a teratogen is introduced during the 5th week of development, this can cause a congenital defect in the tongue.
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.
Clefts account for what percentage of congenital malformations at birth?
15%
What are the #1 and #2 congenital malformations at birth?
#1 Cardiovascular #2 Clefts
How does an oblique facial cleft occur?
Failure to fuse the maxillary process and lateral nasal process.
How would you describe an oblique facial cleft?
There would be a gap from the corner of the mouth out to the ear.
How does a median cleft lip occur?
Failure to fuse the median nasal processes.
How does a bilateral cleft lip occur?
Failure to fuse maxillary and medial nasal processes.
What two deficiencies are associated with clefts? (Main causes of facial clefts.
- Failure of neural crest cells to develop.
- Failure of mesenchyme to proliferate.
What happens if the mesenchyme doesn’t proliferate?
It won’t close the gap between processes.
What happens if the neural crest cells come in at the proper place and time?
Development proceeds correctly.
True or false; primary palate clefts can be isolated or include clefts of the secondary palates.
True
True of false; the failure of shelves to contact is an example of an isolate palatal cleft.
True
True of false; the failure of fusion of shelves because the epithelium is not resorbed is an example of a unilateral primary cleft palate.
False; this is an isolated palatal cleft
Rupture of the structure after fusion or Defective merging/consolidation of mesenchyme are examples of what type of cleft?
Isolated Palatal Cleft
What two types of Clefts have dental influence?
Unilateral primary palatal cleft
Bilateral primary cleft palate
What teeth are effected by a unilateral primary palatal cleft?
Effects the incisors (depends which said the cleft occurs)
What teeth are effected by a bilateral primary cleft palate?
6-#11 canine to canine
What do you often see with palatal clefts?
Lip clefts
What causes a cleft tongue?
The lingual swellings and tuberculum impar fail to merge together.
What results with a partial tongue cleft?
Deep groove in the tongue which is mostly a hygiene issue.
Why does cleft tongue occur?
Failure of epithelial cells to die or mesenchymal cells to proliferate.
Why does Treacher-Collins Syndrome occur?
Failure of neural crest cells to migrate to the facial region.
What is a common feature of a patient with Treacher-Collins Syndrome?
Sagging eyes that pull laterally.
What directs things to happen in a specific way?
Neural Crest Cells
