Development of the Permanent Dentition Flashcards
Tooth eruption sequence
1. Variability
- More so than deciduous dentition,
the sequence is VARIABLE
Tooth eruption sequence
2. Sex differences
Girls are ahead of boys in calcification and
except for the third molars, girls are ahead of boys
by an average of 5 months in eruption
Sequence:
Timing of eruption
1. Timing is
consistent within a dentition –children who erupt any
tooth early or late tend to acquire others early or late
Both sides should erupt at
the same time
Different eruption sequences explain most frequently crowded
teeth:
maxillary cuspids and mandibular second bicuspids
Local influences which hasten permanent tooth
eruption
- If the primary tooth is extracted during active eruption of permanent tooth
(more than 2/3 of the root formed)
Local influences which slow permanent tooth
eruption
When a primary tooth is extracted before active eruption of
permanent tooth (i.e. before root formation)
*Dimensional changes in the Dental Arches
Arch width changes
- Arch width
The increases are tied to
alveolar process growth (both dental eruption and vertical process growth)
Arch width changes
▪Vertical Alveolar Process Growth
▪occurs during
general growth
“spurts”
▪different for maxilla and
mandible: divergent maxillary
process translates into more arch
width growth
Arch width changes
* Dental Eruption
▪ wider placement of the permanent teeth
▪ apposition of alveolar bone to support these teeth will result in
increase in arch width
Maxillary arch
➢increases occur during
➢increases occur during
➢large increase occurs during eruption of the
growth spurts
eruption of incisors
cuspids
PERMANENT DENTITION
Arch — changes
perimeter
Arch perimeter changes
Maxillary arch
▪ Variable(depends on —)
▪ Not difference between —
▪ Factors which limit loss include (3)
pattern of tooth eruption
sexes
greater labial angulation of incisors, greater increases in arch width and smaller leeway space
What about third molars?
(2)
*Prophylactic extraction of impacted teeth is a reasonable option.
*Extraction of third molars to avoid orthodontic relapse has a weak
correlation. Association vs Correlation?
