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8/10/2019 Changes in Mandible
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Mandible At Birth
Anatomical Features of Mandible
Angle170 degree
Sigmoid Notch, Condyle and Coronoid Process
o Sigmoid Notch is shallow
o Condyle is present at one line with the lower border of the
mandible
o Coronoid process is higher than the condyle
Position of Mental Foramen
o
Below the crypt of lower D and lower border of the mandible
Position of Mandibular Canal
o Near the lower border of the mandible
Condition of Teeth
o No teeth erupted but do contain deciduous and
permanent(6s)tooth germs
o Will see crypts or bony compartments where the teeth
grows(A,-E +6)
Mental Protuberance(Chin)
o
No Mental protuberance as the mandible consists of two separate
halves at
birth and they are united in the midline by fibrous tissue. This
area of union is
called symphysis menti
http://education.yahoo.com/reference/gray/illustrations/figure?id=182
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8/10/2019 Changes in Mandible
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Mandible at 3 Years
Anatomical Features of Mandible
Angle140 degree
Sigmoid Notch, Condyle and coronoid process
o Sigmoid Notch becomes deeper than at birth
o Condyle is at a lower level than the coronoid process
Position of Mental Foramen
o Below the socket of the deciduous lower first molar(D)
Position of Mandibular Canal
o
Midway due to increase in height of the alveolar bony socket
Condition of Teeth
o Eruption of all deciduous teeth
Mental Protuberance(Chin)
o Fibrosis tissue of the symphysis menti has been replaced by
bony structure so
symphysis menti is no longer there(usually happens around 12 -18
months)
http://education.yahoo.com/reference/gray/illustrations/figure?id=183
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8/10/2019 Changes in Mandible
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Mandible at 6 years
Anatomical Features of Mandible
Anglesomewhere between 110-140 degreebut it is actually closer
to 110
Sigmoid Notch, Condyle and coronoid process
o Condyle is lower than the coronoid process
o Sigmoid notch is deeper than at 3 years
Position of Mental Foramen
o
Opens nearly midway between upper and lower border of the
mandibular
body
Position of Mandibular Canal
o Mandibular Canal is situated little above the
mylohyoid(midway) line
o Mylohyoidlocated lingually, midway between upper and lower
border
Condition of Teeth
o Mixed dentition periodstarts when the permanent first molar
erupts
Mental Protuberance(Chin)present
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8/10/2019 Changes in Mandible
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Mandible at Adult Age
Anatomical Features of Mandible
Angle110-120 degree
Sigmoid Notch, Condyle and coronoid process
o Sigmoid notch becomes deeper
o
Condyle present at a higher level than coronoid process
Position of Mental Foramen
o Mental foramen is present midway and below the socket of L4
and L5
premolars are not as wide as molars.
o Also present half way between upper and lower borders
Position of Mandibular Canal
o Runs parallel to the mylohyoid line
o Present at the midway between upper and lower borders
Condition of Teeth
o Permanent dentition
Mental Protuberance(Chin)present which gives the characteristic
chin appearance of
the adult. This area has selective deposition(more in male than
female)
http://education.yahoo.com/reference/gray/illustrations/figure?id=184
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8/10/2019 Changes in Mandible
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Mandible at Old Age
Anatomical Features of Mandible
Angle140 degree (oblique angle)
Sigmoid Notch, Condyle and coronoid process
o Sigmoid notch is shallower than in adult
o
Condylar head is more or less bent backward until it is in a
lower level than
coronoid process
Position of Mental Foramen
o Closer to the upper border of the body of mandible due to
resorption of the
alveolar bone
Position of Mandibular Canal
o Closer to the upper border of the body of mandible due to
resorption of the
alveolar bone
Condition of Teeth may loose teeth
Mental Protuberance(Chin) prominent
o Mental protuberance can be very prominent esp when the patient
has lost all their teeth and
have not replaced it. Maxilla is fixed while mandible is notso
for the patient to speak or
eat properly, the mandible must be moved forward to touch the
maxilla. This cause the
muscle under the chin to stretch. The tension of this muscle
cause bone deposition on the
mental protuberance areavery prominent
Dental age is not a persons actual age, it is depended on
whether a person still have his/her teeth.
http://education.yahoo.com/reference/gray/subjects/subject?id=44
