Lec3_Early development

Question 1

In red:

Resorption is rate-______ and a ________ factor.

Answer 1

Resorption is rate-limiting and controlling factor.
Note that deciduous teeth resorb more readily than permanent teeth.
Also, a bracket on a primary tooth will cause it to resorb.

Question 2

In red:

When teeth fail to erupt in primary dentition, how many quadrants can be affected?

Answer 2

Can affect 1 or more posterior quadrants.

The molars and bicuspids might be affected, but the incisors are not.

Question 3

In red:

If teeth failed to erupt, can they be moved down by orthodontic forces?

Answer 3

No, they can not!

Pulling teeth down with braces will cause them to ankylose.

Question 4

What are the rules of thumb for estimating eruption times? (know for exam!!)

Answer 4

1. Teeth erupt when approx 3/4 of root is developed.
2. 2 years are needed for root to finish developing after eruption.
3. Each quarter of the root = 1.5 years.
4. If deciduous tooth is lost before 1/3 of root is formed, have a decreased eruption rate.
5. If deciduous tooth is lost before 1/2 of root is formed, have an increased eruption rate.

Question 5

Know incidence for exam:

What is the incidence for different races for the clefting of lip --primary palate?
Japanese
Caucasians
African-American
Palate only

Answer 5

Japanese - 1:500
Caucasians - 1:800
African-American - 1:2500
Palate only - 1:2500

So, Japanese have highest incidence of cleft lip, and it is more rare to have a palate-only cleft.

Question 6

Know order for exam:

What is the sequence of eruption for permanent teeth?

Answer 6

Max:
Order -- Tooth
1 ----------1st molar
2 ---------centrals
3---------laterals
4---------1st premolar
5-----------canine
6----------2nd premolar
7-----------2nd molar

Mand:
Order -- Tooth
1 ----------centrals
2 ---------1st molar
3---------laterals
4---------canine
5-----------1st premolar
6----------2nd premolar
7-----------2nd molar