MORPHOLOGY OF PERMANENT CANINES

General features:2 Max. 2Mand.Longest toothCorner stone& canine

EminenceHighly developed middle

lab. Lobe(lab. ridge)Lab. &ling. : pentagonal

M&D: triang.Function

-There are two maxillary and two mandibular canines.

-They are called corner stone of the mouth.

-It has long root for good anchorage in the bone.

-The middle labial lobe is well developed forming cusp and labial ridge.

-The bone ridge over the labial surface of the root is called canine eminence (insure facial expression).

The canines are distal to the lateral incisors and are the third teeth from the midline.

111213

MAXILLARY CANINE

2313

26.3

mm

16.2 mm

- The maxillary canine is the third tooth from the midline.

- It is the longest tooth in the mouth (26.3 mm) by virtue of its strongly developed thick single root (16.2 mm).

- Its root is usually the longest of any root with the possible exception of that of the lower canine, which may be as long sometimes.

- The labiolingual measurement of the crown is greater than that of the upper central incisor, while the mesiodistal measurement is less.

- The cingulum is greatly developed than that of the upper central incisor.

Lin Lab. M D

- This tooth has secure anchorage in the maxilla by virtue of its strongly-developed single root which has mesial and distal developmental depressions that help to furnish this anchorage.

D M

-The maxillary canines are often the last teeth to erupt (at about 11-12 years), except for the third molar.

12 years

CHRONOLOGYInitial calcification : 4 – 5 months after birth

Completion of crown: 6 -7years

Eruption : 11 – 12 years

Completion of root : 13 – 15 years

Morphology of the Labial Surface

The crown:

Labial Aspect

The geometric outline of the crown is trapezoid with the smallest uneven arm cervically.

Is usually convex from the cervical line to the mesial contact area.

Distal outline:

Is usually concave between the cervical line and the distal contact area.

Mesial outline:

Nearly at the junction of the middle and incisal thirds of the crown, closer to the cusp tip than is the distal contact point.

In the middle third. Usually it is in the middle of the middle third. It is more cervically located than the mesial contact area.

Contact areas:

Mesial

Distal

The crown labially has a distinct pointed tip called a cusp. This cusp has a mesial slope and a distal slope, which are called mesial and distal cusp ridges.

Cusp Incisal Ridges

D M

The mesial slope is shorter than the distal slope. D

D

M

M

The cusp tip is usually on a line with the center of the root.

DM

Cervical line

Is convex toward the root.

- The single root is long, slender, and conical with a pointed apex.

- Its labial surface is smooth and convex at all points.

- The apical third is curved in a mesial or distal direction, in most cases distally.

The root:

D

DDD M M M

M

The crown

The geometric outline is similar to that of the labial surface.

The crown is narrower lingually than labially.

Lingual aspect

The cingulum is large.

The Cingulum

Mesial and distal marginal ridges usually of moderate size bound the lingual surface mesially and distally.

The distal marginal ridge is slightly more elevated than the mesial marginal ridge.

Mesial and Distal marginal ridges

D M

The mesial marginal ridge is longer than the distal marginal ridge because of the shorter mesial slope and the location of the mesial contact area.

Mesial and Distal marginal ridges “Cont”.

MD

It is a prominent vertical ridge runs from the cusp tip to the cingulum.

Canines are the only teeth that have a prominent lingual ridge.

Lingual ridge

On each side of the lingual ridge a mesial and distal lingual fossae are present. These fossae are usually shallow.

Lingual fossae

D M

The geometric outline of the crown is

wedge-shaped.

Mesial aspect

The entire labial outline is convex from the cervical line to the cusp tip.

The crest of curvature is at the cervical third (cervical ridge).

The labial outline

Is convex in the cervical third. The crest of curvature is on the cingulum, which makes up the cervical third of the crown length.

In the middle third, at the lingual ridge, the lingual outline is slightly concave, then, becomes convex again in the incisal third representing the cusp tip.

The lingual outline

The cusp tip is located labially to the root axis.

The cusp is bulky because of the labial and lingual ridges.

Lab.

Curves toward the cusp (over 2 mm). The cervical convexity of the canine is less marked than that on the incisors.

2mm.

The shape of the crown distally is similar to the crown shape from the mesial aspect, except that the cervical line has less curvature toward the cusp tip.

Distal aspect

- The labiolingual dimension is greater than the mesiodistal.

- The tip of the cusp is labial and mesial to the centers of the crown.

Incisal aspect

DM

CHRONOLOGY

Initial calcification : 4 – 5 month after birth

Completion of crown: 6 – 7 years

Eruption : 9 – 10 years

Completion of root : 12 – 14 years

MANDIBULAR CANINE

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

It closely resembles the upper canine.

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43

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.

-0.8 mm.

+0.4 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.

M

The distal outline:

Labial aspect

The crown

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

D

Incisal outline:

Labial aspect

The crown

The cusp tip is usually on the root axis line.

The cusp is less pointed than that of upper canine.

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

Contact areas

Labial aspect

Mesial In the incisal third .

Distal At the junction of the middle and incisal thirds.

Cervical line

Labial aspect

It is curved toward the root.

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.

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

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.

-0.6

mm

-2 m

m.

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 aspect

The crown taper toward the lingual surface.

The cingulum developed

Lingual aspect

The mesial surface of the crown is wedge-shaped.

The crown mesially is longer than that of upper canine.

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

Mesial aspect

Cervical line

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

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

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

The Root

D.A M.A.

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

Incisal aspect

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

-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.

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