1. UP TO DATE
IN
ORAL BIOLOGY AND EMBRYOLOGY
Prof. Dr. Nahed A. Khalil
Head of Oral Biology Department
&
Contributing Staff Members
Faculty of Oral &Dental Medicine
Cairo University
4. - 1
::CCoolloouurr-- 11
COLOUR
YYEELLLLOOWWIISSHH WWHHIITTEE TTOO
GGRRAAYYIISSHH WWHHIITTEE
:DEPENDS ON
DEGREE OF - 1
CALCIFICATION
HOMOGENISITY OF - 2
THE ENAMEL
.CRYSTALS
:SO
TRANSLUCENT E.
YYEELLLLOOWWIISSHH TEETH
.OPAQUE E
GGRRAAYYIISSHH TEETH
5. TH TTIChhiiKccNkknnEeeSssSss ---22 2
mmmm. at 22..55 –– 22-
.the cusp tips
TThhiinnnniinngg ddoowwnn -
to
featheredge at
the cervical
line of the
tooth
6. HARDNESS – 3
IITT IISS TTHHEE HHAARRDDEESSTT
CCAALLCCIIFFIIEEDD ENAMEL OF TTIISSSSUUEE
THE -
IINN PPEERRMMAANNEENNTT
TTHHEE BBOODDYY
:DDUUEE TEETH TTOO
IS
HIGH HARDER CONTENT THAN
OF - 1
THE THAT MINERAL OF
SALTS
ITS DECIDUOUS
CRYSTALLINE - 2
.ARRANGEMENT
’ONES
IS GREATEST AT - 1 -
THE SURFACE AND
DECREASED TOWARD
.DEJ
IT IS GREATER AT - 2
THE CUSPS AND
INCISAL RIDGE AND
DECREASES TOWARD
.THE CERVICAL LINE
+
-
+
+
+
-
-
7. BR::BBITrriTitttLtlleEennNeeEssSssS-- 44 - 4
Very brittle due to large amount of minerals-
Dentin, which is less mineralized and less brittle, -
compensates for enamel and is necessary as a support
for enamel
If this supportive layer of dentin is destroyed by caries or -
improper cavity preparation, the unsupported enamel
fractures
8. PERMEABILITY- 5
Enamel can act as
a semipermeable
membrane
The main pathway is
from the saliva to the
outer layer of enamel
54. Dentin
Rodless
enamel
Rodless
enamel
Rod
(Prismatic
) Enamel
Ameloblast
without
Tomes
process
ameloblast
without
Tomes
process
Ameloblast
with
Tomes
process
Beginning
secretory
Secretory stage End of secretory
stage