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

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 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 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 (cone-shaped) with a blunt apex

MAXILLARY CENTRAL INCISOR 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 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 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 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 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 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 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 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 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

MAXILLARY LATERAL INCISOR 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 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 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 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 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 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