Development of human dentition Flashcards
When does dental development begin?
6 weeks in utero
When does the first primary tooth emerge?
6 months
When does the first permanent tooth emerge?
6 years
At what age have all crowns begun formation? When doe they finish formation?
5 months and 1 year old respectively
By what age have all primary teeth emerged? Completed root formation?
2.5 years and 4 years respectively
How do incisors in the primary dentition differ from the permanent?
More vertically positioned in the alveolus
More spaced
Greater overbite
What is the relationship between the distal edges of the upper and lower molars in the primary dentition?
There is a flush terminal plane, even distal edges
How does the mandible grow?
Retrudes then quickly grows forward
How much leeway space is seen on the upper and lower?
- 3-1.5mm per side on the top
2. 5-3.1mm per side on the bottom
What happens to the circumference and arch length of the permanent dentition relative to the primary and why?
Decreases because there is a mesial drift of the 1st molar to occupy the leeway space
The terminal plane uses what as a reference point?
The upper 2nd molar
If the terminal plane has a distal step the bite is likely to become?
Full class 2 or end-to-end class 2
A flush terminal plane is likely to become?
End-to-end class 2 or class 1
A mesial step is likely to become?
Class 3 or 1
How can you correct a single tooth crossbite?
Inclined plane
The sac develops into?
The cementum, PDL, and alveolar bone
The outer enamel epithelium becomes?
A protective barrier to the enamel organ
The stellate reticulum becomes?
The enamel matrix
The inner enamel epithelium becomes?
The ameloblasts which form the enamel matrix
The outer cells of the papilla form?
The odontoblasts which form dentin
The inner papilla becomes?
The pulp
What is an early mesial shift?
When the mandibular 1st molar erupts around the age of 6 and closes the primate space resulting in class 1 occlusion
When does occlusion come into alignment in those with a late mesial shift?
Around 11 years old after the primary molars are exfoliated. There are no primate spaces
What is the general eruption sequence of the primary teeth?
ABDCE
CI, LI, 1st molar, canine, 2nd molar
List the eruption sequence of the teeth, differentiate between upper and lower
A lower, A upper, B upper, B lower, D upper, D lower, C upper, C lower, E lower, E upper
List when each primary tooth erupts
A lower- 6-8 months A upper- 7-10 months B upper- 8-11 months B lower- 9-13 months D upper- 12-15 months D lower- 12-16 months C upper- 16-19 months C lower- 17-20 months E lower- 20-26 months E upper- 25-28 months
How much root formation is needed before a tooth will emerge?
1/2-2/3
Describe the eruption sequence for the upper permanents?
6, 1, 2, 4, 5, 3, 7, 8
For the lower permanents?
6, 1, 2, 3, 4, 5, 7, 8
Describe the age of eruption for the upper teeth
6 is between 6-7 1 between 7-8 2 between 8-10 4 and 5 are 10-12 3 is 11-13 7 is 11-13 8 is 17-20
Describe the age of eruption for the lower teeth
6 and 1 are 6-7 2 is 7-8 3 is 8-10 4 is 10-12 5 and 7 are 11-13 8 is 17-20
