Transcript Dentition * Deciduous teeth

Dentition – Deciduous teeth
• There are 20 primary teeth (10 at every jaw):
– 8 incisors, 4 canines and 8 primary molars.
• By 4 months in utero: Teeth begin to form in bone
• By Age 2: All deciduous or ‘baby’ teeth have erupted
Dentition – Permanent Teeth
• There are 32 permanent teeth (16 at every jaw):
– 8 incisors, 4 canines, 8 premolars, and 12 molars
• By Age 6: Permanent teeth have started to erupt
• By Age 12: Second set of molars have emerged
• Age 17-24: Wisdom teeth have erupted
Dentition
• The number of teeth of each type of tooth is
written as a dental formula for one side of the
mouth.
• The teeth are numbered in order:
– Incisors, Canines, Premolars, Molars
– I:C:P:M
• Juvenile skull less than
6-7 years old.
• Dentition: 2:1:2
–
–
–
–
2 incisors
1 canine
2 premolars
0 molars
• Skull from a 12 year old
male.
• Dentition: 2:1:2:2
–
–
–
–
2 incisors
1 canine
2 premolars
2 molars
– Wisdom tooth is under
the surface of the gum
• Adult male skull
• Dentition: 2:1:2:3
–
–
–
–
2 incisors
1 canine
2 premolars
3 molars
Human developmental phases and general
characteristics used for aging
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Perinatal
Neonate
Infant/toddler
Late childhood
Adolescence
Early adulthood
Middle and late adulthood
Perinatals - before birth
• The age of perinatals, individuals not yet
born, can be determined by looking at bone
size.
• This is a fairly accurate estimate due to the
fact malnourishment will not affect growth;
the fetus will take necessary nutrients from
the mother.
Neonates ~ 0-6 or 7 months
• Prove very difficult to accurately determine
the age because of individual variation of
development (genetics & nourishment).
• Neonates have no teeth
• Areas of the skeleton have not fused together
(especially the cranium and pelvis).
Infants and toddlers 6 or
7 months ~ 2 years
• All (20) deciduous teeth erupted by age 2.
• Permanent teeth (under ‘baby’ teeth) start to
form at birth, thus the formation of
permanent teeth is a relatively good age
determinant.
• Some ossification has begun, this is highly
variable at this age
Late childhood ~ 6 years -11 years
• Late childhood is when the permanent teeth
begin to come in.
• More bones begin to ossify.
• Second set of molars come in at about age 12.
Adolescence ~12- 18 years
• Adolescence shows increased long bone
length and fusion of the ends (or cap) to the
shaft.
• This epiphyseal union/fusion is a particularly
useful age technique. (see skeletal diagrams
for age references).
Age range ~ 20 – 35 ish
• Young adults and older adults have several
methods of age determination:
• closure of the cranial sutures; morphology of
rib-ends,
• pubic symphysial
• microstructure of bone and teeth; wear on
teeth, incremental layers of cementum
• Age of epiphyseal
fusion.
• First number is
approximate age at
which fusion first
begins.
• Second number is
approximate age at
which fusion is
complete.
Diagram of human
shoulder and arm
• Practice Q’s
• Region A has just begun to fuse
• Region B, fusion is
approximately 90% complete.
• There is a complete epiphysial
union at location C.
• Fusion at distal end of radius
and ulna is approximately 5060%.
• What is the approximate age of
this person?
Answer… Age 18-20
Age range 18-25
Age range 15-19
Age range 13-18
Age range 15-23
Practice Q’s…
• Description of partial skull and partial pelvis
found in a remote wooded area:
• Skull - coronal suture is approximately 60%
fused, lamboidal suture is fused and semi
smooth, frontal area (forehead) has a 40 0
angle.
• The subpubic angle is approximately 50 0, and
the pubic bone (pubic symphysis) is completely
fused.
• What is the sex and age of this individual?
Answer….
• Skull - coronal suture is approximately 60%
fused,( age range 30-35) lamboidal suture is
fused and semi smooth (age range closes at
30, get more snooth over time), frontal area
(forehead) has a 40 0 angle (male less than 90
0).
• The subpubic angle is approximately
50 0,(male 50-800) and the pubic bone (pubic
symphysis) is completely fused (age 20-23) .
Adult dentition and age range of tooth
eruption
Frontal view of adult dentition, numbers for
identification and tooth name.
Maxilla of female
found in wooded
area after a suicide.
Did this woman have
her wisdom teeth?
Maxilla of female
found in wooded
area after a suicide.
Did this woman have
her wisdom teeth?
YES
2:1:2:3