1. MORPHOLOGY OF PERMANENT CANINES
Dr. Firas Alsoleihat, BDS, PhD
Dental Morphology
Department of Conservative Dentistry

2. Introduction/Morphology /Function/Location
Human canines are the longest and most stable of teeth in the dental arch. Only one tooth of this class is present in each quadrant. In traditional dental literature, canines are considered the cornerstones of the dental arch. They are the only teeth in the dentition with a single cusp. They are especially anchored as prehensile teeth in the group from whence they get their name, the Carnivora.
Maxillary canines by definition are the teeth in the maxilla distal, but closest to the incisors. Mandibular canines are those lower teeth that articulate with the mesial aspect of the upper canine.

3. The permanent canines Eruption sequence No type traits Class traits
Lower before upper
No type traits
Class traits
The most stable
Longest & thickest roots LL
Single conical cusp
Only cusped teeth without
occlusal surface
Support the arch and
facial musculature
Arch traits
Upper larger than lower
Smaller IC / MD proportion
in maxillary canine

4. The maxillary canine Labial aspects
The canine is approximately 1 mm narrower than the central incisor. 
Its mesial aspect resembles the adjacent lateral incisor; the distal aspect anticipates the first premolar proximal to it.
The canine is slightly darker and more yellow in the color than the incisor teeth. 
The labial surface is smooth, with a well developed middle lobe extending the full length of the crown cervically from the cusp tip.
Cusp tip is on a line bisecting the tooth MD
Incisal outline has 2 sloping ridges
Mesial ridge sloping less markedly and shorter than distal
Mesial HOC is at the junction between incisal and middle thirds
Distal HOC is at the middle portion of the crown
Mesial outline is slightly convex
Mesial cusp slope might exhibit slight concavity
Distal outline is markedly concave
Distal cusp slope is straight or slightly convex
CEJ is slightly convex
Labial surface
Labial ridge
Slight depressions on either sides, but more distally
Root is long & narrow

5. The maxillary canine Lingual aspect Crown & root narrower lingually
Distinct mesial and distal marginal ridges, a well-devloped cingulum, and the cusp ridges form the boundries of the lingual surface.
Well-elevated marginal ridges (arch trait)
Accentuated cingulum – slightly
concave at midpoint (arch trait)
Pronounced lingual ridge (arch trait) extending from the cusp tip to the cingulum, dividing the lingual surface into mesial and distal fossae.
ML & DL fossae
A lingual pit and/or developmental grooves
Mesial aspect
The mesial and distal aspects present a triangular outline. They resemble the incisors, but are more robust--especially in the cingulum region.
Cusp tip labial to a line bisecting the tooth LL
Thick cervical third
HOCs are just cervical to the junction between cervical and middle thirds
From HOC labially the outline is straight toward cusp tip
Lingual outline starts cervically convex
then slightly concave then convex again
Thick incisal ridge LL (arch trait)
Root is wide with a slight longitudinal
concavity and blunt apex

6. The maxillary canine Distal aspect Deeper and longer longitudinal
concavity on the root
Less curvature for CEJ
Incisal aspect
 It usually thicker labiolingually than it is mesiodistally. 
The tip of the cusp is displaced labially to the central long axis of this tooth.
Asymmetry
Distal half has a concavity
on the labial outline
Mesial part of the labial outline is convex
Prominent convexity of the cingulum
Pulp
Double convex lens shape in LL section,
widest near cervix
Narrow in MD section
Right and Left: The distal surface is fuller and more convex than the mesial surface. The mesial contact point is at the junction of the incisal and middle third. Distally, the contact is situated more cervically. It is at the middle of the middle third.
Variation: In some persons, a cusp-like tubercle is found on the cingulum. Lingual pits occur only infrequently. On occasion, the root is unusually long or unusually short.

7. Maxillary Canine

8. The mandibular canine Narrower MD and LL (arch trait)
Smaller MD/IC proportion (arch trait)
Labial surface
The crown length is equal or longer by 0.5 to 1 mm
The root is usually shorter but sometimes as long as the maxillary canine.
In an individual person, the lower canine is often shorter than that of the upper canine.
Cusp is not as long & pointed as in maxillary (arch trait)
The labiolingual diameter of crown and root is usually a fraction of a millimeter less. Mesio-distally it is narrower.
Mesial cusp ridge is shorter and high adjacent to cusp tip
When the tooth is unworn, the mesial cusp ridge appears as a sort of 'shoulder' on the tooth.
Distal cusp ridge is lower
Incisal outline = 1/4 to 1/5 IC height
Mesial outline is straight while distal is convex
Both converge slightly toward the cervix
Mesial HOC is just below MI angle (within the incisal third) while
Distal HOC is between incisal & middle thirds
The crowns of the mandibular canines appear longer than maxillary canines due to the narrowness of the crown mesiodistally and the height of the contact areas above the cervix.
The cusp tip is in line with the center of the root mesio-distally , as on the maxillary canine
A distinctive feature is the nearly straight outline of the mesial aspect of the crown and root. 
Root is conical with blunted apex
Mesial inclination from cervix to apex
Crown appears tilted distally in relation to root long axis

9. The mandibular canine Lingual aspect Marginal ridges, lingual ridge
& cingulum are less prominent
ML & DL fossae are shallower
The lingual surface is smooth and regular.
The lingual ridge, if present, is usually rather subtle in its expression.
Pits or grooves are rare
Root narrower lingually than labially
Distinct longitudinal depressions
extends down proximal surfaces
The lingual portion of the root is narrower relatively than that of the maxillary canine. It narrows down to little more than half the width of the labial portion.
Mesial aspect
The mesial and distal aspects present a triangular outline.
Cusp tip with long axis of the tooth
Cervical third is narrower
HOCs are just above CL &
entire labial outline is convex
Root is narrower and root tip more pointed
CL curves more toward the incisal portion than in the maxillary canine.
Mesial developmental depression is more pronounced than in The max. canine
incisal portion of the crown is thinner labiolingually, which allows the cusp to appear more pointed and the cusp ridge to appear more slender.
When the crown and root are viewed from the proximal, this tooth uniquely presents a crescent-like profile similar to a cashew nut.

10. The mandibular canine Distal aspect Incisal aspect Pulp
Similar to mesial
CL curves less toward the incisal portion than in the maxillary canine.
Incisal aspect
The mesiodistal dimension is clearly less than the labiolingual dimension. 
M & D halves are more nearly symmetrical
Lingual outline is less round
Less bulky appearance of the incisal edge
The cusp tip and mesial cusp ridge are more likely to be inclined in a lingual direction
Pulp
Similar to maxillary canine
Variation: On occasion, the root is bifurcated near its tip. The double root may, or may not be accompanied by deep depressions in the root.

11. chronology Mandibular Canine Maxillary Canine
First evidence of calcification:4-5 mo
Enamel completed:6-7yr
Eruption:9-10yr
Root completed:12-14yr
Maxillary Canine
First evidence of calcification:4-5mo
Enamel completed:6-7yr
Eruption:11-12yr
Root completed:13-15yr

12. Comparative Anatomy: Canines of Interest in other Species
In mammals, canines are single rooted teeth adapted for tearing food. They are often the largest teeth in the mouth. In humans they are much reduced in size. This condition permits the side-to-side motion in the human chewing cycle. In many species canines project well beyond the level of the other teeth and may interlock when the teeth are closed (preventing side-to-side motion).
Rodents don't have canines at all. The tusks of the wart hog, barbirussa, and the extinct sabre tooth cat are canines of dramatically increased size. The most typical offensive specialization in mammalian teeth is represented by the canines.

13. Comparative Anatomy: Canines of Interest in other Species
Smilodon, the saber-tooth cat is now extinct. Well known from La Brea in Los Angeles County, this spectacular animal had continuous growing maxillary incisors over 6 inches in length. This carnivore died out 10,000 years ago and may have been encountered by the First Americans who came from Siberia. The tusk-like canines were probably used to attack large, thick-skinned animals such as the mammoth and giant sloth.

14. Comparative Anatomy: Canines of Interest in other Species
The walrus, a pinniped related to seals and sea lions, lives on a specialized diet of shellfish. All of its teeth are reduced to blunt, cone-like structures except for the tusk-like continuously growing canines. They are used to scoop up seaweed and for locomotion on ice when out of the water.

15. Comparative Anatomy: Canines of Interest in other Species
Baboons and sexual dimorphism. Among many animals, the tusk-like development of canines is a much more predominate feature in the male animal than in the female. Examples are the pigs, deer, baboons, and the anthropoid apes. In many animals, the larger and stronger tusks of the male animals are used in fighting--often the combat for exclusive access to females. Baboons use them for threatening displays; as such, canines are 'social teeth.‘
Horses present an unusual dental sexual dimorphism: in females, the already reduced canines may be rudimentary or may be absent altogether.

16. Comparative Anatomy: Canines of Interest in other Species
The pig family present highly developed weapon teeth. In wild pigs, the canines are huge tusks projecting outside the mouth cavity, which continue to grow and erupt throughout life.The male wart hog (the wild boar), has canines of the upper jaw that may turn upward and attain a length of 8 to 10 inches. They are used for digging roots and as formidable weapons in combat. In the Hebrides Islands, aboriginal peoples will break out the upper canines, causing the lower ones to grow into fanciful spirals that are used for ornamental purposes.

17. Comparative Anatomy: Canines of Interest in other Species
The babirussa, the wild pig of Malaysia, has upturned canines in the upper jaw that are actual extraoral teeth that grow up through the roof of the snout. The teeth sweep back to the forehead, sometimes attaining a length of seventeen inches. These remarkable teeth in the male are probably sexual ornaments; in the female, they are mere nubs.

22. Canine relationship
Class I
Class II
Class III