MANDIBULAR CANINE

Prof. A. El-Sahn

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Initial calcification : 4 – 5 month after birth

Completion of crown: 6 – 7 years

Eruption : 9 – 10 years

Completion of root : 12 – 14 years

CHRONOLOGY

Prof. A. El-Sahn

The mandibular canine is the third tooth from the midline of the mandible.

It closely resembles the upper canine.

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Prof. A. El-Sahn

Its features are less well developed than those of upper canine.

Its crown appears long and narrow compared with that of upper canine.

It is actually 0.4 mm. longer and 0.8 mm. narrower.

Prof. A. El-Sahn

+0

.4 m

m.

-0.8 mm.

The crown

Labial aspect

The mesial outline:Is nearly straight from the cervical line to

the mesial contact area, then continues to the cusp slope.

It is nearly in line with the mesial side of the root and does not project or bulge beyond the root outline.

Prof. A. El-Sahn

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The distal outline:Labial aspect

Is slightly concave in the cervical third, then, it becomes convex incisally.

It projects beyond the root outline. The distal outline is shorter than the mesial outline.

From this aspect the crown appears to be tilted or bent distally due to the difference in mesial and distal outlines.

Prof. A. El-Sahn

D

Incisal outline:

Labial aspectThe crown

The cusp tip is usually on the root axis line.

Its slopes form a more obtuse angle than those of upper canine.

The cusp is less pointed than that of upper canine.

Prof. A. El-Sahn

The mesial slope of the cusp is shorter than the distal slope, more so than on maxillary canine.

The mesial cusp slope is also in a more nearly horizontal plane compared to the longer distal cusp slope, which slopes more severely in an apical direction.

Incisal outline : (Cont.)

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Contact areas:

Labial aspect

Mesial In the incisal third just below the mesioincisal angle.

Distal At the junction of the middle and incisal thirds, more cervically located than the mesial contact area.

Prof. A. El-Sahn

Cervical line:Labial aspect

It has a semicircular curvature root ward.

Prof. A. El-Sahn

Morphology of the labial surface

The labial surface is smooth and convex.

It often shows a labial ridge, which is not as prominent as on the upper canine.

Morphology of the labial surface cont.

Shallow vertical depressions may be present on either side of the labial ridge in the incisal third.

The incisal third of the crown is slightly flattened mesial and distal to the labial ridges.

Prof. A. El-Sahn

The root The root is shorter than that

of the upper canine by 0.6 mm to 2 mm.

Its apical end is more sharply pointed.

Its apical end is more often straight than curving toward mesial or distal sides.

The root is convex on the labial surface.

Prof. A. El-Sahn

-0.6 mm

-2 mm

.

The lingual surface of the crown resembles those of the lower incisors in being smooth, However;

A faint lingual ridge is running from the cusp tip to the cingulum.

Lingual aspectThe crown

The crown taper toward the lingual surface.

Prof. A. El-Sahn

The marginal ridges are not prominent.

The mesial marginal ridge is longer and straighter than the shorter, more elevated and curved distal marginal ridge.

The cingulum is poorly developed

Lingual aspectThe crown cont.

Prof. A. El-Sahn

The lingual portion of the root is narrower than that of the upper canine.

The lingual surface of the root is convex.

The Root

Prof. A. El-Sahn

The mesial surface of the crown is wedge-shaped.

The crown mesially is longer than of upper canine.

The crown is narrower labiolingually than the upper canine (by 0.4 mm).

Mesial aspect

The Crown

Prof. A. El-Sahn

The labial outline has less curvature than that of upper canine with very little crest of curvature directly above the cervical line.

The lingual outline is similar to that of the upper canine. The cingulum is not prominent.

Incisally: the incisal portion of the crown is thinner labiolingually.

Mesial aspect

Prof. A. El-Sahn

The cusp appears more pointed.

The tip of the cusp is most often located slightly lingual to the root axis line, but it may be centered over it.

Mesial aspect

Prof. A. El-Sahn

Curves more incisally than does the cervical line on upper canine.

Cervical line:

The root surface is similar to that of the upper canine from the mesial aspect except:

The root tip is more pointed than that of upper canine.

The developmental depression mesially is more pronounced than that on upper canine.

Prof. A. El-Sahn

The Root

Distal aspect

The distoincisal angle is slightly more lingual in position than the cusp tip because of the distolingual twist of the crown (similar to the lower lateral incisors).

The cervical line curvature is less on the distal surface than on the mesial surface.

Prof. A. El-Sahn

The general shape from the distal aspect is similar to the shape from the mesial aspect.

The vertical developmental depression on the distal side of the root is often deeper than the depression on the mesial side.

The Root

Prof. A. El-Sahn

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Incisal aspect The outline of lower canine

from the incisal aspect is often similar to that of upper canine.

The labiolingual dimension of the crown is longer than the mesiodistal dimension similar to upper canine.

Prof. A. El-Sahn

The cusp tip is more likely to be inclined lingually.

Labially, the mesiolabial outline is more convex while the distolabial outline is flat or concave

The distal cusp slope is directed slightly lingually from the cusp tip, which places the distoincisal angle in a lingual position to the cusp tip.

Incisal aspect

Prof. A. El-Sahn

DM

The crown tapers lingually and the cingulum is represented by a curved line.

Prof. A. El-Sahn

- This lingual placement of the distoincisal angle gives the incisal part of the crown a distolingual twist like lower lateral incisor. This twist matches closely the curvature of the dental arch.

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