Mixed Dentition- Dr. Retrouvey (FINAL) Flashcards
The difference is sizes of the primary anterior incisors & the permanent anterior incisors:
Incisor liability
Lower permanent incisors erupt _____ to the primary
How does this affect the arch size?
Lingually; Arch size decreases
Upper permanent incisors erupt ____ to the primary
How does affect the arch size?
Labially/facially; Arch size increases
Dental arch measurements include (4):
- Arch length
- Arch width
- Arch perimeter
- Intercanine distance
Measured at the midline to a tangent touching the distal surfaces of the secondary primary molar
Arch length
Arch length (depth) is measured at the midline to a tangent, touching the ____ surfaces of the _____
Distal surfaces; second primary molars
The arch length is stable one the:
Permanent incisors are in
If one sees “growth” of the arch length after the primary incisors are in, this is due to _____ not actually due to ____
DISPACEMENT; NOT growth
Arch length changes include:
- Lose arch length in lower arch (due to lower incisor eruption)
- Gain arch length in the upper arch (due to upper incisor eruption)
Measured between the cusps of the canine tips in the transverse plane:
Arch width
Measured between the occlusal grooves of the second primary molars:
Arch width
Arch widths are given in ____ measurements
Two different which allows you to estimates of the transverse development of the arches
Although “there are no significant changes from primary to mixed dentition in the lower arch width”
there is about 4mm of changes between ages:
4-12 years
Intercanine distance increases until age ____ in girls & ____ in boys
10-11 years girls
11-12 years boys
(+3-4 mm
Measured from the distal surface of the second primary molar around the arch, over the contact points & incisal edges in a smoothed curve:
Arch perimeter
Arch perimeter before treatment is referred to as the:
Baseline
The elongation of the roots has nothing to do with:
Tooth eruption
(rather the crown is pulling the root)
From ____ to ___ years old, the primary dentition is replaced by the permanent dentition resulting in mixed dentition
6 to 13
The permanent first molars erupt to the ____ of the primary dentition (no primary tooth replacement)
distal
First, second & third molars do not:
Replace primary dentition
(they erupt distal to primary dentition)
Primary root resorption is a result of:
Permanent tooth eruption
Permanent tooth eruption causes:
Primary root resorption
Put the following events in order:
(a) Primary tooth starts to resorb
(b) permanent root develops
(c) crown of permanent tooth is formed
- Crown of permanent tooth is formed
- permanent root develops
- Crown of permanent tooth is formed
When does the primary tooth exfoliate & permanent tooth erupt?
When the primary root is totally resorbed
What happens when the primary root is totally resorbed?
The primary tooth exfoliates & the permanent tooth erupts
When does the permanent tooth stop erupting?
when it reaches the occlusal plane or contacts an opposing tooth
What gives the power to cause the primary root to resorb/baby tooth to exfoliate?
Permanent tooth eruption
Permanent tooth
What do we mean “root development is NOT a main factor in eruption”
The root forms at the same time that the tooth erupts (IT DOES NOT PUSH THE CROWN UP)
You should not do a panoramic X-ray before the age of:
8
(too complex to distinguish with mixed dentition)
For eruption of permanent dentition, there are variable patterns between:
3-4-5
(canine, 1st P, 2nd P) <— ?
Tooth replacement sequence is variable in terms of: (5)
- Sequence
- Timing
- Position
- Numbers
- Shape
What are the tooth eruption patterns for teeth 3, 4, 5:
-3,4,5
-4,3,5
-4,5,3
(Note: it doesn’t start with 5)
At the age of 13 years, describe what the dentition should look like:
most permanent teeth should be in
The root of the permanent tooth has to be _____ formed PRIOR to extraction of primary tooth
2/3 formed
Variability in tooth number can be a result of:
ethnicity
Congenitally missing teeth are rare, effecting _____ % of the population
3-5
What is the most frequently congenital tooth in Caucasian population?
Maxillary lateral incisor
What are two common congenitally missing teeth?
- maxillary lateral incisor (most frequent)
- mandibular second premolar
A missing primary tooth= _____ meaning ____
no permanent successor= delayed eruption
Affects the growth of the alveolar processes:
Ankylosis
Refers to the fusion of part of the root of the primary tooth to the underlying bone which stops the tooth from erupting:
Ankylosis
Ankylosis may be due to localized defective during eruption process, in the _____ whereby _____
PDL; Osseous
Ankylosis becomes more prevalent in mixed dentition where occlusal level of ankylosed tooth:
Does NOT keep up with vertical level of the adjacent teeth
What is responsible for keeping the teeth in contact during growth & may play a role in ankylosis:
Dentoalveolar development
Treatment of ankylosis usually invovles:
Simply monitor these teeth (50% self correction)
If an ankylosed tooth fails to correct itself/fails to exfoliate, it may be advisable to:
Extract the tooth to avoid damages to the permanent dentition
When the tooth is growing in the complete wrong position
Ectopic eruption
The most common tooth displaying an ectopic eruption is the:
mandibular canine
