266
Tooth Morphology
SECTION II
VARIATIONS
1.
Sexual dimorphism:
Maxillary canines exhibit
sexual dimorphism (the systematic difference in
form between individuals of different sex).
2.
Bushman canine:
It is an extra ridge on the me-
sial slope of canine, commonly seen in blacks.
3.
Tuberculum dentale:
It refers to tubercles near
the cingulum.
4.
Distal accessory ridge:
It is an extra ridge on
the distal marginal ridge.
CLINICAL CONSIDERATIONS:
MAXILLARY CANINES
1. The maxillary canines support the lip and the
facial muscles. They form the cornerstone of the
dental arches. Restorations involving canines
should be done keeping this in mind because
they have a significant impact on the aesthetics.
2. Maxillary canines are less likely to be affected by
dental caries and periodontal problems as their
morphology permits self-cleansing activity and
increased anchorage.
3. Maxillary canines are impacted frequently due
to reduced arch space. Surgical exposure and
further orthodontic treatment is required to
align them properly.
4. They play a very important role in phonetics
(speech).
5. During lateral excursions or movements of the
mandible, the upper and lower canines come
in contact and prevent the posterior teeth from
contacting. This canine guidance is considered
the most physiologic of all occlusal relation-
ships because it protects the posterior teeth
from wear.
MANDIBULAR CANINE
The mandibular canines are similar to maxillary ca-
nines but narrower mesiodistally and labiolingually.
The crown height of mandibular canine is slightly
longer than that of the maxillary canine.
The chronology and dimensions of mandibular
canines are stated in Boxes 14.3 and 14.4.
LABIAL ASPECT (FIG. 14.10)
1.
Shape of the crown:
The crown of the mandib-
ular canine is trapezoidal.
Box 14.3
Chronology of Mandibular Canines
1. First evidence of calcification: 4 months
2. Enamel completion: 7 years
3. Eruption: 9–10 years
4. Root completion: 13 years
Box 14.4
Dimensions of Mandibular Canines
1. Length of the crown: 11 mm
2. Length of the root: 16 mm
3. Mesiodistal width of the crown: 7 mm
4. Mesiodistal width of the crown at cervix: 5.5 mm
5. Labiolingual width of the crown: 7.5 mm
6. Labiolingual width of the crown at cervix: 7.0 mm
7. Depth of curvature at the mesial aspect: 2.5 mm
8. Depth of curvature at the distal aspect: 1 mm
Figure 14.10
Labial aspect of the mandibular canine.
Mesial outline is
nearly straight
(b)
Longer distal
cusp ridge
(a)
Cervical
line—semicircular
curvature
towards apex
Short mesial
cusp ridge
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