05 Development of Dentition Flashcards
When does the calcification of the primary teeth begin?
3.5-4.5 months after conception
The first teeth to erupt are the mandibular centrals, what age?
6-7 months
What tooth is the last to erupt? What month does this happen?
Maxillary 2nd Molar (AJ)
26 months
Which dentition shows less variability
Primary
The primary occlusion changes in order to adapt to these two things
Skeletal growth
Occlusal wear
At what stages of dental calcification and development are girls more advanced than boys?
All stages
When do teeth start to move occlusally
Not until crown formation is complete
What physical characteristic of teeth is determined genetically
Tooth size
There are relationships between these three genetically related conditions
Dental agenesis
Delayed development
Diminished size of teeth
Which condition is more likely:
Congenitally missing teeth or Supernumerary teeth?
Congenitally missing
Are congenitally missing teeth more likely in boys or girls
boys
Are changes in the width of the dental arch timed more closely to dental development or skeletal growth?
Dental development
When does dental arch circumference decrease?
During the late transitional and early permanent dentition
What surfaces are determinant factors in the initial permanent molar occlusion?
Distal of primary 2nd molars
Which teeth show the greatest variability in development
3rd moalrs
What is the order of calcification of primary teeth?
A, B, C, D, E
What is ABCDE
A = Centrals B = Laterals C = Canines D = First Molars E = 2nd Molars
In what order do the cusps of posterior teeth calcify?
MB
ML
DB
DL
How many calcification centers are there in anterior teeth
one
Which tooth erupts at 6 months
Mn Centrals
Eruption = 7 Months
Mn Lats
Eruption = 7.5 Months
Mx Centrals
Eruption = 9 Months
Mx Lats
Eruption = 12 Months
Mn 1st Molar
Eruption = 14 Months
Mx 1st Molar
Eruption = 16 Months
Mn Canine
Eruption = 18 Months
Mx Canine
Eruption = 20 Months
Mn 2nd Molar
Eruption = 24 Months
Mx 2nd Molar
Initiation times for permanent Centrals, Lats, Canines, 1st PMs
5 months IU
Initiation times for 2nd Premolars
10 months PP
Initiation times for 1st Molars
20 weeks IU
Initiation times for 2nd molars
12 months PP
Initiation times for 3rd molars
5 years PP
What is the length of time for root completion for primary teeth?
18 months Post eruption
What is the length of time for root completion for permanent teeth
3 years post eruption
What is the range of eruption times for primary teeth
6 months to 24-36 months
Only 1% of kids don’t have their first tooth by this age
12 months
Only 1% of kids have a tooth before this age
4 months
By the age of 12 months, the average kid has this many teeth
6-8
Rarely do kids have less that this many teeth at 12 months
2
Rarely do kids have more than this many teeth at 12 months
10
90% of all kids have all of their primary teeth by this age
3 years
why is the sequence of eruption more important that the time of eruption
it determines the position of the teeth in the arch
What conditions that have anecdotally been related to teething have been proven to be unrelated to teething?
Respiratory infections
Fever convulsions
Bronchitis
Exczema
60 % of infants exhibit these symptoms before and after eruption
Rhinorrhea
Irritability
Diarrhea
Macknin et al found the following symptoms significantly associated with teething
Increased biting Drooling Gum rubbing Sucking irratability Wakefulness Ear rubbing Facial rash Decreased appetite for solid foods Mild Fever (<101)
We should know the liquid that is contained in these common child products
Teething rings
What treatment is needed for an eruption hematoma
None!
What are neonatal teeth
Teeth that erupt within the first 30 days of life
What are premature teeth
Teeth erupted earlier than 3 months of age
What are natal teeth
Teeth that have erupted before birth
What is more common, natal teeth or neonatal teeth
Natal 3:1
How common/rare are natal teeth
1:2000
What percent of natal teeth are true primary teeth
90%
What condition is associated with Natal/Neonatal Teeth
Riga-Fede Disease
What is Riga-Fede Disease
Tongue trauma from feeding
What two syndromes are associated with natal and neonatal teeth
Chondroectodermal Dysplasia
Cleft lip and palate
What is another name for Chondroectodermal Dysplasia
Ellis-van Creveld
What is Chondroectodermal Dysplasia
Inherited bone growth disorder that can cause dwarfism and tooth deformity
What are three structures in newborns that can be confused for neonatal teeth
Dental lamina cysts
Bohn’s nodules
Epstein’s Pearls
Is Baume Type I spaced or not spaced
Spaced
Where are the maxillary primate spaces
Mesial of canine
Where are the mandibular primate spaces
Distal to canines
Why are the primate spaces important
Canine and bicuspid eruption
Does the total interdental spacing between primary teeth increase or decrease with age?
Decrease
What is the most common terminal plane relationship
Mesial (60%) Class I
What does the Primary Molar Terminal Plane help determine
Transitional occlusal pattern of the permanent molars
How is the orientation of primary incisors different from permanent incisors
Primary = Upright with little overbite and overjet
Perm = Labial angulation and greater overbite and overjet
Why does the intercanine width of the mandibular arch increase only slightly with the eruption of the permanent incisors
Due to the divergent nature of the distal movement of the primary canine into the primate spaces
What is the leeway space of Nance
the combined mesio-distal widths of deciduous canines and molars differ from those of permanent canines and premolars by 0.9 mm in Mx and 1.7 mm in Mn
What is the early mesial shift?
The eruptive force of the permanent molar causes the generalized spacing to close allowing the permanent molar to shift into a class I occlusion
When does the late mesial shift happen
when no primate spaces exist the shift occurs when the second primary molar exfoliates in the mandible before the maxilla
What should we know about Anodontia
That if you are missing the primary tooth completely, you will never develop the permanent tooth
Histopathology Initiation
Problems of tooth #
Histopath Proliferation
Problems of tooth #, size, proportion, twinning
Histopath Histodifferentiation
Problems of enamel and dentin
Histopath Morphodifferentiation
Problems of size, shape
Histopath Appostition
Enamel hypoplasia, dentin dysplasia, hypercementosis, enamel pearls
Histopath Mineralization and Maturation
Flourosis, localized hypomineralizaton, interglobular dentin
Anomolies of Initiation and Proliferation
Hyperdontia
Hypodontia
Anodontia
What syndromes are associated with Hyperdontia
Apert Cleidocranial dysplasia Gardner's Crouzon's Down's
What syndromes are associated with Hypodontia and Anodontia
ED
Crouzon’s
Achondroplasia
Ellis Van Creveld
Which teeth are the most frequently congenitally absent
3rd Molars
Mn 2nd Premolars
Mx Lats
Mx 2nd premolars
Anomalies of Proliferation and Morphodifferentiation
Microdontia
Macrodontia
Most frequent Microdontia teeth
Laterals
2nd PM
3rd Molars
Conditions with Microdontia
ED Ellis Van Creveld Hemifacial microsomia Down Crouzon
Conditions with Macrodontia
Hemifacial hypertrophy
Crouzon
Otodental Syndrom
Anomalies of Proliferation and Morphodifferentiation 2
Gemination
Twinning
Fusion
Concrescence
What is gemination
Single pulp, split crown, more common in primary
What is Twinning
Single bud w/supernumerary image
2 separate crowns
What is fusion
more common in primary teeth
2 separate pulp chambers
What is concrescence
Fusion that occurs after root formation is completed
Anomalies in Morphodifferentiation
Dens Invaginatus
Den Evaginatus (Talon Cusp)
Taurodontism
Dilaceration
