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hardest material in the body, but brittle
enamel
TERM 2
enamel is _% inorganic
DEFINITION 2
TERM 3
enamel is _% organic material and water
DEFINITION 3
TERM 4
the inorganic mineral in enamel
DEFINITION 4
Hydroxyapatite
TERM 5
a protein that makes up the organic portion of
enamel
DEFINITION 5
Enamelin
enamel forms _ predentin has been deposited
by odontoblasts in the dental papilla
after
TERM 7
After predentin is deposited, ameloblasts,
assisted by the _ _, secrete a protein matrix
(_)
DEFINITION 7
stratum intermedium cells; amelogenin
TERM 8
The enamel forms in
DEFINITION 8
continuous rods
TERM 9
Because the enamel is thicker in the occlusal
surface of the tooth than the cervical area the
enamel rods are
DEFINITION 9
longer in the occlusal area
TERM 10
In the cervical area the rods run
DEFINITION 10
almost perpendicular to the tooth surface
The head of an enamel rod is rounded & is
formed by _ ameloblast
TERM 17
The tail looks like a fishtail & is formed by _
different ameloblasts
DEFINITION 17
TERM 18
Each rod is filled with
DEFINITION 18
hydroxyapatite crystals (inorganic 96%)
TERM 19
In the head of an enamel rod, crystals are
oriented in the _ _ of the rod
DEFINITION 19
long axis
TERM 20
In the tail of an enamel rod, crystals are
oriented in the _ _ of the rod
DEFINITION 20
cross-axis
microscopic enamel structures
Hunter-Schreger bands, Incremental lines, Enamel lamellae,
Enamel tufts, Enamel spindles
TERM 22
HUNTER-SCHREGER BANDS
DEFINITION 22
Groups of rods bend to the left or right of adjacent rods &
when light is projected at the surface of a thin slab of enamel,
light & dark bands appear & extend about one-half to two-
thirds of the thickness of the enamel. This arrangement
provides strength
TERM 23
INCREMENTAL LINES are also
called
DEFINITION 23
lines of Retzius
TERM 24
INCREMENTAL LINES are
DEFINITION 24
bands or cross-striations on the enamel rods that, when seen
in cross-section, seem to traverse the enamel rods
TERM 25
Incremental lines are caused by
DEFINITION 25
incremental deposition of enamel matrix & its subsequent
mineralization (active deposition followed by a period of
inactivity)
Possible causes of ENAMEL LAMELLAE
some form during enamel development, stress cracks
caused by impact or temperature change
TERM 32
ENAMEL LAMELLAE are not tubular, but
appear _, extending around the crown
DEFINITION 32
leaflike
TERM 33
_ _ are possible avenue for dental
caries
DEFINITION 33
ENAMEL LAMELLAE
TERM 34
ENAMEL TUFTS
DEFINITION 34
Defects between groups of enamel rods that are filled with
organic material (enamelin)
TERM 35
ENAMEL TUFTS are located at
DEFINITION 35
the DEJ & extend 1/5 to 1/10 distance from DEJ to surface of
the tooth at right angles to the DEJ
ENAMEL SPINDLES
Odontoblasts occasionally penetrate & extend through the
DEJ & enamel forms around this process, may contain an
odontoblastic process, they appear as fingerlike spindles
TERM 37
The enamel surface may be smooth or have
fine ridges, called _ (_ _)
DEFINITION 37
perikymata (imbrication lines)
TERM 38
perikymata (imbrication lines) are caused
by
DEFINITION 38
variations in deposition of enamel in adjacent areas of the
enamel
TERM 39
perikymata (imbrication lines) are more
prominent
DEFINITION 39
on the facial surface of the tooth near the cervical areas
TERM 40
minute spaces between or around enamel
rods
DEFINITION 40
microlamellae
