Morphology Of Permanent Canines

MORPHOLOGY OF PERMANENT CANINES

Oral Histology Dent 201 Summer semester 2005/2006

The permanent canines ❧ Eruption sequence ●

Lower before upper

❧ Function ❧ No type traits ❧ Class traits ● ● ● ●

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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 Greater IC / MD proportion in maxillary canine

The maxillary canine ❧ Labial aspects ● ●

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 • MI angle is higher and more rounded than DI angle

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Mesial HOC is close to the incisal margin Distal HOC is at the middle portion of the crown Mesial outline is slightly convex Distal outline is markedly convex CEJ is slightly convex incisally Labial surface • Labial ridge • Slight depressions on either sides

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Root is long & narrow

The maxillary canine ❧ Lingual aspect ● ● ●

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Crown & root narrower lingually Well-elevated marginal ridges (arch trait) Accentuated lingual cingulum – slightly concave at midpoint (arch trait) Pronounced lingual ridge (arch trait) ML & DL fossae A lingual pit and/or developmental grooves marking the inner boundaries of marginal ridges

❧ Mesial aspect ● ● ● ● ●

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Cusp tip labial to a line bisecting the tooth LL Thick cervical third HOC is between cervical and middle thirds From HOC outline is straight toward cusp tip Lingual outline starts cervically convex then slightly concave then convex again HOC is close to cervical line Thick incisal ridge LL (arch trait) Root is wide with a slight longitudinal concavity and blunt apex

The maxillary canine ❧ Distal aspect ●

Deeper and longer longitudinal concavity on the root

❧ Incisal aspect ●

Asymmetry • Distal half is wider & has a concavity on the labial outline • Mesial part of the labial outline is convex

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Prominent convexity of the cingulum 3 distinct lobes

❧ Pulp ●

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Double convex lens shape in LL section, widest near cervix Narrow in MD section

Maxillary Canine

The mandibular canine ❧ Narrower MD and LL (arch trait) ❧ Smaller MD/IC proportion (arch trait)

Labial surface ● ● ● ● ●

Cusp is not as long & pointed as in maxillary (arch trait) Mesial cusp ridge is high adjacent to cusp tip Distal cusp ridge is low Incisal outline = 1/4 to 1/5 IC height Mesial outline is straight while distal is convex • Both converge slightly toward the cervix

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Mesial HOC is just below MI angle while DI angle is between incisal & middle thirds 3 lobes & 2 depressions on the labial surface Root is conical with blunted root • Mesial inclination from cervix to apex • Crown appears tilted distally in relation to root long axis

The mandibular canine ❧ Lingual aspect ●

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Marginal ridges, lingual ridge & cingulum are less prominent ML & DL are shallower Pits or grooves are rare Root narrower lingually than labially Distinct longitudinal depressions extends down proximal surfaces

❧ Mesial aspect ● ● ●

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Cusp tip with long axis of the tooth Cervical third is narrower HOC is just above CL & entire labial outline is convex Root is narrower

The mandibular canine ❧ Distal aspect ●

Similar to mesial

❧ Incisal aspect ● ● ● ●

M & D halves are more nearly symmetrical Lingual outline is less round Less bulky appearance of the incisal edge Vertical lobe grooves are less marked

❧ Pulp ●

Similar to maxillary canine

 Canine relationship ❧ Class I ❧ Class II ❧ Class III