Transcript maxillary central incisor

PERMANENT MAXILLARY
INCISORS
PERMANENT MAXILLARY INCISORS
• the maxillary incisors are four in number
• the maxillary central incisors are centered in the
maxilla, one on either side of the median line
with the mesial surface of each in contact
with the other.
• shearing or cutting teeth
• their major function is to punch and cut food
material during the process of mastication.
• have incisal edges or ridges rather than cusps
MAXILLARY CENTRAL INCISOR
- widest mesiodistally of any of the anterior teeth
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LABIAL ASPECT
average crown length is 10 to 11 mm long
from the highest point on the cervical line
to the lowest point on the incisal edge.
mesiodistal measurement is 8 to 9 mm wide
at the contact areas.
The crown is narrowest in the cervical third
and becomes broader toward the incisal
third
The mesial outline of the crown is only
slightly convex, with the crest of the
curvature approaching the mesioincisal
angle
MAXILLARY CENTRAL INCISOR
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LABIAL ASPECT
Mesioincisal angle is slightly rounded
and distoincisal angle is more rounded
Distal outline of the crown is more
convex than the mesial outline , the
crest of the curvature being higher
toward the cervical line
Distoincisal angle is not as sharp as the
mesioincisal angle
The incisal outline is usually regular
and straight in a mesiodistal direction
after the tooth has been in function long
enough to obliterate mamelons
MAXILLARY CENTRAL INCISOR
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LABIAL ASPECT
The cervical outline of the crown follows
a semicircular direction with the
curvature root-wise
The outline and shape of the root is
much like an ice cream cone (coneshaped) with a blunt apex
MAXILLARY CENTRAL INCISOR
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LINGUAL ASPECT
the large lingual fossa, immediately
incisal to the cingulum and bounded by
the two marginal ridges is developed
the cingulum on this tooth is usually
well-developed and is located off-center
toward the distal.
The mesial and distal marginal ridges
vary in prominence on the central
incisors from one person to another
Due to the distal placement of the
cingulum, the mesial marginal ridge is
longer than the distal marginal ridge
MAXILLARY CENTRAL INCISOR
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LINGUAL ASPECT
Small or narrow lingual ridges may be
present which extend vertically from the
cingulum toward the center of the fossa
There may be a lingual pit at the incisal
border of the cingulum where the mesial
and distal marginal ridges come
together.
The lingual surface of the root is convex
and is narrower mesiodistally than the
labial surface
The root is flattened on the mesial side
approaching the lingual side.
MAXILLARY CENTRAL INCISOR
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MESIAL ASPECT
the crown is wedge shaped, or
triangular with the base of the triangles
at the
cervix and the apex is the incisal ridge
labially and lingually, immediately
coronal to the cervical line are the crests
of curvature
the
cervical
line
outlining
the
cementoenamel junction mesially curves
incisally to a noticeable degree (greater
curvature on the mesial aspect than on
the distal
MAXILLARY CENTRAL INCISOR
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MESIAL ASPECT
the root from this aspect is cone shaped
and the apex is usually bluntly rounded
the mesial surface of the root is
somewhat flattened with a longitudinal
depression in the middle third
MAXILLARY CENTRAL INCISOR
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DISTAL ASPECT
the crown gives the impression of being
somewhat thicker toward the incisal third
because of the slope of the labial surface
distolingually, more of the surface is seen
from the distal aspect creating an illusion of
greater thickness.
the curvature of the cervical outlining the
CEJ is less in extent on the distal than on
the mesial surfaces
the shape of the distal root surface is
similar to the shape from the mesial aspect
except that its surface is convex rather than
flattened and it does not have a depression
MAXILLARY CENTRAL INCISOR
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INCISAL ASPECT
from this aspect, the labial face of the
crown is relatively broad and flat in
comparison with the lingual surface
the outline of the lingual portion tapers
lingually toward the cingulum
the crown outline is noticeably wider
mesiodistally than faciolingually
the cingulum is off-center to the distal,
resulting in the mesial marginal ridge
measuring longer than the distal
marginal ridge
MAXILLARY LATERAL INCISOR
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resembles a maxillary central incisor but
smaller in all dimensions except in root length
there is a great morphologic variation in this
tooth
it may be asymmetrical, pointed form (peg
lateral), or entirely missing
LABIAL ASPECT
although the crown is smaller in all
dimensions, its proportions usually
correspond to those of the central incisor
it has more curvature with a rounded
incisal ridge and rounded incisal angles
mesially and distally
MAXILLARY LATERAL INCISOR
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LABIAL ASPECT
the mesial outline of the crown from the
labial aspect resembles that of the central
incisor, with more rounded mesioincisal
angle
the distal outline is always more rounded,
and the crest of contour is more cervical,
usually in the center of the middle third
the labial surface of the crown is more
convex than that of the central incisor
except in some square and flat-faced forms
this
tooth
is
relatively
narrow
mesiodistally, usually about 2mm narrower
than the central incisor
MAXILLARY LATERAL INCISOR
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LABIAL ASPECT
its root length is greater in proportion to
its crown length than that of the central
incisor
the mesioincisal angle is more acute and
the distoincisal angle is wider or more
obtuse than on the central incisors
the incisal edge slopes cervically toward
the distal
Crown contact areas from the labial
Mesial – in the incisal third or near the
junction of incisal and middle thirds
 Distal – more cervical than the mesial
contact area at the junction of incisal and
middle thirds or in the middle third
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MAXILLARY LATERAL INCISOR
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LABIAL ASPECT
the root tapers evenly from the cervical
line to a point approximately two thirds
of its length apically
the root curves sharply from this
location in a distal direction and ends in
a pointed apex ( although the curvature
distally is typical, some roots are
straight )
MAXILLARY LATERAL INCISOR
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LINGUAL ASPECT
mesial and distal marginal ridges are
marked and the cingulum is usually
prominent
the linguoincisal ridge is well-developed
and the lingual fossa is more concave
and more pronounced than on the
central incisor
as on the central incisor, there may be
small vertical accessory lingual ridges
on and incisal to the cingulum, only
they are fewer in number and less
common
the root is narrower on the lingual side
than on the labial side
MAXILLARY LATERAL INCISOR
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MESIAL ASPECT
the mesial aspect of the maxillary
lateral incisor is similar to that of a
small central incisor except that the
root appears longer
the crown is shorter, the root is
relatively longer, and the labiolingual
measurement of the crown and root is a
millimeter or less than the maxillary
central incisor of the same mouth
the curvature of the cervical line is
marked in the direction of the incisal
ridge
MAXILLARY LATERAL INCISOR
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MESIAL ASPECT
the root appears as a tapered cone from
this aspect
the labial outline of the root from this
aspect is straight
similar to the central incisor, a shallow
longitudinal depression is often found
on the middle of the mesial surface
extending about half of the root length
MAXILLARY LATERAL INCISOR
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DISTAL ASPECT
the width of the crown distally appears
thicker than it does on the mesial aspect
from marginal ridge to labial face
the curvature of the cervical line is
usually a millimeter or so less in depth
than on the mesial side
MAXILLARY LATERAL INCISOR
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INCISAL ASPECT
this tooth exhibit more convexity
labially and lingually from the incisal
aspect than maxillary central incisors
on some lateral incisors, the mesiodistal
measurement
and
labiolingual
measurement are the same
the cingulum is centered mesiodistally