Arch Development and Space Flashcards
dental age
age equivalence
- based on the # of teeth
chronological age
age of years from birth
normal vs ideal
normal does not mean ideal
ideal means
a condition that is scientifically “best” but makes no assumptions on its prevelance ina group
factors effecting development
genetics – calcification erupton
nutrition – like malnutrition can affect the size, proportion, quality and texture of the teeth
chronic ilness - major illness can affect the tooth devlopment
race –
socioeconmic
pre-natal development
within fetus - ectomesenchymal reaction
all 20 primary teeth begin calcification during the pre-natal period
central primary calcification begins
14 week in utero
lateral primary calcification begins
16 week in utero
canine primary calcification begins
17 week in utero
implication – like if something happened at 17 weeks could notice in the canine of the child
1st molar primary calcification begins
15 week in utero
2nd molar primary calcification begins
19 week in utero
18 week in utero for mandibular
natal teeth
occasionally at birth – but usually doesnt begin to erupt until at least 6 month of age
range of noraml eruption
usually within 6 months back and forth
eruption sequence vs timing
sequence – usually same but the time could be different for people
1/2 2/3 of root formaitno
will likely come into the cavity or be able to with help
primate spaces
mandibular between canines and first molars
maxillary - between lateral and canines
generalized spacing in the primary dentition is a requirement for proper alignment
crown completion, eruption and root completino for max and mand central primary
max
1.5 month
10 month
1.5 yhears
mand
2.5 month
8 month
1.5 year
crown completion, eruption and root completino for max and mand primary lateral
2.5 month
11 months
2 year
3 month
13 month
1/5 year
crown completion, eruption and root completino for max and mand primary canine
9 month
19 month
3.25 years
9month
20 month
3.25 year
crown completion, eruption and root completino for max and mand primary 1st molar
6 month
16 month
2.5 year
5/5 month
16 month
2.25 year
crown completion, eruption and root completino for max and mand primary 2nd molar
11 month
29 month
3 year
10 month
27 month
3 year
neonatal ring
around primary teeth - noting the clacification difference when born
a-b-d-c-e
sequence
incirosr first
pre-emergent eruption of permanent teeth
as the crown is being formed there is a smalllabial drift of the follicle within the bone, not attributed to eruption forces
eruptive forces bein soon after the root begins to form
two forces in eruption - like for it to occur
- resorption of bone and primary tooth roots
2. eruption of the permanent tooth in the path that has been cleared
root forms in what direction
apically - pushes down while crown moves up and pushes the primary root up
permanent teeth relationship to primary
lingual to primary
like cnetral incisor is lingual to A and lateral incisor lingual to central
pot emergent eruption phase when
instance of first gingival penetration until the tooth reaches the occlusal level
speed of pre and post
post is much faster –
post-emergent spurt
starts frominstance of first gingival penetration until the tooth reaches the occlusal level
once the OCCLUSAL PLANE is reached
juvenile occlusal equilibrium
after the spurt – slow eruption phase – equals the vertical growth rate of the ramus in a normally growing adult
adult occlusal equilibrium phase
after all facial growth is complete – this phase remains active throughout life
at night?
spurts of micro movement in teeth
jevenile occlusal equilibrium is achieved by
eruptive forces pushing coronally and occlusal forces pushing apically
calcification of 1st molar
32 week in utero
everything else after birth
calcification of 3rd molar
8 - max
9- mand
in years
general rule if tooth is ready to erupt - or will
1/2 to 2/3 - ready to start erupting
then 2-3 years later will start to erupt
clinical emergence of permanent teeth occurs
when 2/3 to 3/4 roots are developed
most common sequence of erruption develops into a ___
class I occlusion with 90.6%
canine eruption in permanent? general
after bicuspids in maxillary
before bicuspids in mandibular
mixed dentition starts? ends?
when eruption of the 1st permanent tooth (mandibular 1st molar) erupts distal to primary second molar
ends
- when the loss of the last deciduous tooth occurs
usually maxillary deciduos canines
non succedaneous teeth
1st 2nd and 3rd molars
remember that each quadrant 5 permanent teeth (2 incisors, canine, and 2 pre-molars replalce five primary teeth)
dental age 5
eruption tendencies of permanent incisors and the first molars
all primary teeth in and developed
eruption tendencies in incisors
dental age 6
eruption of mandibular 1st molar
max first molar
mandibular central incisor
dental age 7
eruption of max central incisor and mandibulr lateral incisor
dental age 8
eruption of max lateral incisor
delay of 2-3 years before any further teeth erupt
dental age 9-10
root development of canines and premolars and resorption of the primary roots
*important time for x-rays
dental ages 9-11
range
permanent canines start to point down mesially towards lateral incisor apical area
Temporary incisor spacing and distal tipping –> ugly duckling stage
usually as it peaks in into the later roots – pears to be flared out
- this is normal
“ugly duckling stage”
ages 9-11
corresponding to temporary incisor spacing and distal tipping
dental age 11
eruption of mandibular canine
mandibular 1st pre-molars
maxillary 1st premolars
dental age 12
should see max and mand second pre molar
maxillary canine
2nd molars
max or mandibular canine first?
mandibular (age 11 ish usually)
dental age 13-15
roots of all permanent teeth complete except the 3rd molars
crown formation of the 3rd molars
AGE WITH primary teeth WITH ADDITION OF FIRST MOLARS, central incisors and lateral incisors
8 year old
picture of mandible with permanent 4 incisors and first molars and one of the permanent canines
10 years old around
example with all permanent with 1st molars, incisors, pre molars ad one maxillary canine
no primary teeth left
11-12
example of mandibular arch with second molars (e) still in place
- have first pre-molars and canine-canine erupting
see NO second premolar
10 1/2 - 11
if max second molars are there - what age should we think?
12 years old
three relationships of molars in PRIMARY teeth
- distal step - where maxillary upper is positioned mesial to the lower molar
flush terminal plane – max and mand distal planes are in line
mesial step - when the maxillary molar is distal to the mandibular molar creating a mesial step
step is in relation to the mandibular primary
class II usually from
distal step
growth in relaiton to the primary dentition molar classificatin
DISTAL STEP if growth is little --> class II and with forward growth will go to end to end
FLUSH TERMINAL PLANE - little growth -- end to end - forward growth of mandible --> class I
MESIAL STEP - little growth -- class I
forward growth of mandible Class III
normally mesial step will form>
class I
percentage of primary dentiont that ends as class I, II, III, end to end?
I- 55%
II- 19%
III- 1%
end to end – 25%
important
MESIAL STEP very exxageratted together with spacing and drifting and mesial growth horizontal of mandible
class III
distal step always
class II
exaggerated mesial step
class III
flush plane is ..
very variable
maxillary arch dimensional change in canine
5 mm increase - BIcanine
gets wider - grow more bucally
maxillary arch width dimensional change in molar?
4 mm increase
more change seen in the canine - canine span
maxillary arch length ?
DECREASES SLIGHTLY
mesail of first molar or distal of primary second molar to buccal of centrals
primary molars are wider than the permanent pre-molars
transverse line
maxillary arch circumferential change?
1 mm increase
mandibular atch width dimensional change
bicanine 3mm increase
bimolar 2mm increase
mandibular arch length dimenional change
1 mm decrease
maxillary see a slight decrease as well
mandibular arch circumference change?
yes
DECREASE IN 4MM
VS MAXILLARY IS 1 MM INCREASE
LEEWAY SPACE / E SPACE
MESIO-DISTAL width of primary canine, first molar, and second molar
compared to the M-D width of permanent canine, 1st and 2nd pre-molars
leeway space on maxilla and mandible?
max = 1.2 mm
mandible = 3.1 mm
implication of leeway space in adequate
crowding – the most common feature of malocclusion
prevent need of future extractions?
diagnose and early treat crowding
-
space required
the actaual measurement of each permanent tooth material between the first permanent molars
measure each tooth with calibrater - M-D width of each tooth in front of first molars
space avaialbel
measured arch perimeter mesial to the first permanent molars
discrepency between space avaialble and space required results?
in either spacing or crowding
space avaialbel - space required
determine space available/ required with not all permanent teeth in?
Hixon -Oldfather technique
Hixon -Oldfather technique
- measure premolar widths from x-ray of same side
(like the erupting ones) - measure incisors (centrals and laterals) on SAME SIDE
- ADD THOSE
- REFER TO A TABLE - PREDICTION CHART
- final step –> measure actual space available from distal of lateral incisor to mesial of first molar and compare to prediction
GET THE PREDICTED VALUE OF COMBINED PERMANENT CANINE AND PRE-MOLAR WIDTH
Hixon -Oldfather technique
GET THE PREDICTED VALUE OF COMBINED PERMANENT CANINE AND PRE-MOLAR WIDTH
from pre-molar on -ray and measuring the central and later M-D and adding
arch length discrepancy
space available - space required = arch length discrepancy
negative value from equation of space analysis vs +
negative = crowding
positive = spacing
