Primary Tooth development and eruption

Question 1

Where does the development of teeth take place?

Answer 1

In the maxillary and mandibular arches

Question 2

When does primary dentition develop?

Answer 2

During both the embryonic period And fetal period

Question 3

When does the permanent dentition form?

Answer 3

During the fetal period

Continues for years after birth, teeth have the longest developmental period of organs

Question 4

What is enamel organ?

Answer 4

Highly specialized epithelial tissue that forms enamel

Question 5

What are Dental papilla

Answer 5

Embryonic connective tissue that forms Dentin and pulp

Question 6

What is the dental follicle/sac

Answer 6

Embryonic connective tissue that encapsulates the developing tooth. Forms cementum, PDL, And alveolar bone

Question 7

What is a bone crypt or “alveoli”

Answer 7

Space in which the developing tooth forms in the developing alveolar ridge

Question 8

What happens during the initiation stage of tooth development? When does it happen?

Answer 8

Happens at the 6th to 7th week

Main process is induction. The dental lamina connect the developing tooth bud to the epithelial layer of the mouth

Question 9

When does the bud stage occur and what happens?

Answer 9

Happens at the eighth week

Main process is proliferation. The growth of dental lamina into a bud shape that penetrates growing extomesenchyme (emergence of enamel organs)

Question 10

When does the cap Stage occur, and what happens?

Answer 10

9th to 10th week

This is when proliferation, differentiation, morphogenesis occur. Differentiation of enamel organ into bell shape with four cell types and dental papilla into two cell types

Question 11

What is the apposition stage

Answer 11

Induction and proliferation occur. Dental tissue types secreted in successive layers as a matrix

Question 12

What is the maturation stage

Answer 12

Dental tissue types fully mineralize to their mature form

Question 13

What happens at the time of eruption?

Answer 13

The crown is completely formed and root is partially formed (neither are fully calcified)

Crown penetrates the oral mucosa and enters the oral cavity

Question 14

What are the other words for primary/deciduous dentition. How many primary teeth are there in all?

Answer 14

Temporary, baby, milk teeth

20 teeth

Question 15

How many teeth are in the primary dentition?

Answer 15

20 total: 4 incisors, 2 canines, 4 molars (per arch)

Question 16

What are the functions of primary teeth?

Answer 16

Mastication
Speech
Esthetics
Saves space for succedaneous permanent teeth

Question 17

Benefits of preventing premature loss of primary teeth

Answer 17

Maintains comfort/function
Maintains occlusion of primary teeth
Prevents malocclusion of permanent teeth

Question 18

When does the formation of primary teeth begin?

Answer 18

In utero- 6 to 8 weeks

Question 19

When does calcification of primary teeth begin?

Answer 19

I’m utero- 13 to 16 weeks

Question 20

When does eruption of the primary teeth take place? When will they be completely erupted with fully formed roots?

Answer 20

From age 6-30 months

And

Age 2-3 years

Question 21

Which arch usually precedes the other in primary eruption? What is the order of appearance?

Answer 21

Mandibular is usually seen first

Central incisors
Lateral incisors
1st molars
Canines
2nd molars

Question 22

When do we see erupting dentition occur?

Answer 22

Ages 6mos- 3years. Occurs over about 2 years

Question 23

When do we see complete dentition occur?

Answer 23

Ages 3-7 years. Over the course of 5 years

Question 24

When do we see mixed dentition?

Answer 24

Ages 7-11 years. Over the course of 5 years

Question 25

What is exfoliation in primary dentition?

Answer 25

- The shedding of deciduous teeth. - Precedes the eruption of succedaneous teeth - Roots must resorb to make room for permanent teeth and so they may shed/exfoliate

Question 26

Effects of exfoliation on the permanent dentition

Answer 26

- Can impact occlusion of permanent teeth if primaries are lost prematurely (drifting teeth/loss of space for new teeth) - can also impact occlusion if they are retained for too long. Can prevent eruption or cause map position of succedaneous teeth

Question 27

What are the most unstable teeth in the primary dentition?

Answer 27

``` Maxillary incisors (prey to trauma) Max & mand molars (prey to decay) ```

Question 28

Common anomalies in primary dentition

Answer 28

- Bruxism- especially on anterior teeth - Attrition- wear patterns - Primary/primate spacing- beneficial to erupting permanent teeth- gives more space

Question 29

What is mixed dentition? When does it begin and with which teeth?

Answer 29

The transition of primary to permanent dentition. Begins at about age 6 with the eruption of the mandibular central incisors and/or the mandibular first molars

Question 30

Why are the mandibular permanent first molars often the first permanent teeth to irrupt before any deciduous teeth exfoliate?

Answer 30

Because they are not succedaneous. They erupt distal to the deciduous second molars

Question 31

How many pre-molars are in the primary dentition?

Answer 31

None, they only exist in the permanent dentition. Primary molars are replaced by the succedaneous permanent pre-molars

Question 32

Characteristics of the primary maxillary first molar

Answer 32

Resembles permanent maxillary first premolar

Question 33

Characteristics of the primary maxillary second molar

Answer 33

Resembles the permanent maxillary first molar

Question 34

Characteristics of the primary mandibular first molar

Answer 34

Does not resemble any mandibular permanent posterior tooth

Question 35

Characteristics of the Primary mandibular second molar

Answer 35

Resembles permanent mandibular first molar

Question 36

How many routes are on the maxillary and mandibular primary molars?

Answer 36

Three roots on maxillary primary molars Two roots on mandibular primary molars Number of roots are the same as permanent molars

Question 37

Major contrasts of primary crowns to permanent crowns

Answer 37

-Overall they are smaller -Anteriors are wider mesial to distal -Posteriors are wider buccal to lingual -whiter, less pigmented -enamel is relatively thin and consistent in depth except on cervical ridges -buccal/lingual cervical ridges are more prominent (esp on max/mand 1st molar) -thickness of Dentin is limited but greatest in the occlusal fossa -cervical area is narrower mesial to distal 

Question 38

Major contrast of primary roots to permanent roots

Answer 38

Primary are narrower; posterior roots are widely flared

Question 39

Major contrast of primary pulp horns to permanent pulp horns

Answer 39

Primary are high and pulp chambers are large

Question 40

Major contrast of crown widths between primary and permanent teeth

Answer 40

Crowns are larger in comparison with root cervix and trunk

Question 41

Major contrast between root canals of primary and permanent teeth

Answer 41

Are long and narrow in primary teeth; molar roots flare and thin rapidly towards the apices

Question 42

 major contrast in endodontic procedures from primary teeth to permanent teeth

Answer 42

Pulpotomy- only the coronal pulp is removed from primary teeth Pulpectomy- all pulp is removed, coronal and radicular, from permanent teeth

Question 43

What is meant by flush terminal plane? What does this allow for?

Answer 43

The primary maxillary and mandibular second molars are in an end to end relationship Allows the proper molar relationship to occur in the permanent dentition

Question 44

What is meant by mesial step? What will this most likely allow for?

Answer 44

The mandibular second molar is mesial to the maxillary molar Will most likely allow the proper permanent molar relationship to occur in the permanent dentition

Question 45

What is meant by distal step? Is this a beneficial relationship?

Answer 45

Primary mandibular second molar is distal to the maxillary second molar Not a beneficial molar relationship. May prevent the proper molar relationship in the permanent dentition

Question 46

When is eruption completed?

Answer 46

When the crown of the erupting tooth contacts it’s antagonist

Question 47

When is root formation completed?

Answer 47

When the apical foramen is formed

Question 48

What is the current theory on what causes exfoliation?

Answer 48

The increased pressure/forces of maturing muscles of mastication cause the primary teeth to begin to resorb and shed As well as the remodeling of the periodontal ligament

Question 49

Periods of stability in primary teeth

Answer 49

Is short overall. Some teeth may be lost by age 4, five teeth missing by age 6 and only six teeth remaining by age 10