Primary Tooth development and eruption Flashcards
Where does the development of teeth take place?
In the maxillary and mandibular arches
When does primary dentition develop?
During both the embryonic period And fetal period
When does the permanent dentition form?
During the fetal period
Continues for years after birth, teeth have the longest developmental period of organs
What is enamel organ?
Highly specialized epithelial tissue that forms enamel
What are Dental papilla
Embryonic connective tissue that forms Dentin and pulp
What is the dental follicle/sac
Embryonic connective tissue that encapsulates the developing tooth. Forms cementum, PDL, And alveolar bone
What is a bone crypt or “alveoli”
Space in which the developing tooth forms in the developing alveolar ridge
What happens during the initiation stage of tooth development? When does it happen?
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
When does the bud stage occur and what happens?
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)
When does the cap Stage occur, and what happens?
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
What is the apposition stage
Induction and proliferation occur. Dental tissue types secreted in successive layers as a matrix
What is the maturation stage
Dental tissue types fully mineralize to their mature form
What happens at the time of eruption?
The crown is completely formed and root is partially formed (neither are fully calcified)
Crown penetrates the oral mucosa and enters the oral cavity
What are the other words for primary/deciduous dentition. How many primary teeth are there in all?
Temporary, baby, milk teeth
20 teeth
How many teeth are in the primary dentition?
20 total: 4 incisors, 2 canines, 4 molars (per arch)
What are the functions of primary teeth?
Mastication
Speech
Esthetics
Saves space for succedaneous permanent teeth
Benefits of preventing premature loss of primary teeth
Maintains comfort/function
Maintains occlusion of primary teeth
Prevents malocclusion of permanent teeth
When does the formation of primary teeth begin?
In utero- 6 to 8 weeks
When does calcification of primary teeth begin?
I’m utero- 13 to 16 weeks
When does eruption of the primary teeth take place? When will they be completely erupted with fully formed roots?
From age 6-30 months
And
Age 2-3 years
Which arch usually precedes the other in primary eruption? What is the order of appearance?
Mandibular is usually seen first
Central incisors Lateral incisors 1st molars Canines 2nd molars
When do we see erupting dentition occur?
Ages 6mos- 3years. Occurs over about 2 years
When do we see complete dentition occur?
Ages 3-7 years. Over the course of 5 years
When do we see mixed dentition?
Ages 7-11 years. Over the course of 5 years
What is exfoliation in primary dentition?
- 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
Effects of exfoliation on the permanent dentition
- 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
What are the most unstable teeth in the primary dentition?
Maxillary incisors (prey to trauma) Max & mand molars (prey to decay)
Common anomalies in primary dentition
- Bruxism- especially on anterior teeth
- Attrition- wear patterns
- Primary/primate spacing- beneficial to erupting permanent teeth- gives more space
What is mixed dentition? When does it begin and with which teeth?
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
Why are the mandibular permanent first molars often the first permanent teeth to irrupt before any deciduous teeth exfoliate?
Because they are not succedaneous. They erupt distal to the deciduous second molars
How many pre-molars are in the primary dentition?
None, they only exist in the permanent dentition. Primary molars are replaced by the succedaneous permanent pre-molars
Characteristics of the primary maxillary first molar
Resembles permanent maxillary first premolar
Characteristics of the primary maxillary second molar
Resembles the permanent maxillary first molar
Characteristics of the primary mandibular first molar
Does not resemble any mandibular permanent posterior tooth
Characteristics of the Primary mandibular second molar
Resembles permanent mandibular first molar
How many routes are on the maxillary and mandibular primary molars?
Three roots on maxillary primary molars
Two roots on mandibular primary molars
Number of roots are the same as permanent molars
Major contrasts of primary crowns to permanent crowns
-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

Major contrast of primary roots to permanent roots
Primary are narrower; posterior roots are widely flared
Major contrast of primary pulp horns to permanent pulp horns
Primary are high and pulp chambers are large
Major contrast of crown widths between primary and permanent teeth
Crowns are larger in comparison with root cervix and trunk
Major contrast between root canals of primary and permanent teeth
Are long and narrow in primary teeth; molar roots flare and thin rapidly towards the apices
 major contrast in endodontic procedures from primary teeth to permanent teeth
Pulpotomy- only the coronal pulp is removed from primary teeth
Pulpectomy- all pulp is removed, coronal and radicular, from permanent teeth
What is meant by flush terminal plane? What does this allow for?
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
What is meant by mesial step? What will this most likely allow for?
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
What is meant by distal step? Is this a beneficial relationship?
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
When is eruption completed?
When the crown of the erupting tooth contacts it’s antagonist
When is root formation completed?
When the apical foramen is formed
What is the current theory on what causes exfoliation?
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
Periods of stability in primary teeth
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
