More Tooth Identification
Posterior
Posterior
Maxillary
First Premolar
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These premolars have bifurcated roots. A
Longitudinal groove is present on the root.
The mesial surface shows a developmental
fossa. The mesial marginal groove crosses
the mesial marginal ridge and extends onto
the mesial surface. The facial cusp is wider
and longer than the lingual cusp. The mesial
ridge of the facial cusp may have a slight
concavity.
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Number of roots – 2
Number of pulp horns – 2
Number of cusps – 2
Number of developmental lobes - 4
Second Premolar
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These premolars usually have a single root.
About 40% have two root canals. The buccal
and lingual cusps are nearly equal in length.
The buccal cusp is shorter than that of the
first premolar. The entire crown, especially
the occlusal outline, is less angular and more
rounded. The occlusal developmental
grooves are shorter, shaloower, and more
irregular.
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Number of roots – 1
Number of pulp horns – 2
Number of cusps – 2
Number of developmental lobes - 4
First Molar
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A cusp of Carabelli (5th cusp) may be
present. The occlusal outline is square or
rhomboidal rather than triangular. The
distolingual cusp is well developed. There is
a prominent oblique ridge and distal facial
and lingual grooves. The crown is nearly as
wide mesiodistally as buccolingually. The
three roots are widely seperated.
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Number of roots – 3
Number of pulp horns – 4
Number of cusps – 5
Number of developmental lobes - 5
Second Molar
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These teeth are similar to the first molars
except that the 5th cusp is usually absent and
the distolingual cusp is less developed. The
oblique ridge is less prominent. The crown is
shorter occlusocervically and narrower
mesiodistally. The occlusal outline of the
drown is rhomoidal to heart shaped. The
three roots are less seperated.
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Number of roots – 3
Number of pulp horns – 4
Number of cusps – 4
Number of developmental lobes - 4
Third Molar
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These teeth vary more in form than the
others. They usually do not have a
distolingual cusp. The occlusal outline is
heart shaped, with three cusps. The roots,
usually three, have a tendency to be very
close together or to fuse with an extreme
distal inclination.
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Number of roots – 1 to 4
Number of pulp horns – 1 to 4
Number of cusps – 3 to 5
Number of developmental lobes - 4
Posterior
Mandibular
First Premolar
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These premolars have two cusps, one large buccal
and one small lingual. The buccal cusps are
centered directly over the root. The lingual cusps
are centered lingual to the root and are afunctional
and nonoccluding. The occlusal surface slopes
sharply lingual in a cervical direction. The
mesiobuccal cusp ridge is shorter than the
distobuccal ridge. It has a mesiolingual
developmental groove and one root.
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Number of roots – 1
Number of pulp horns – 1 or 2
Number of cusps – 2
Number of developmental lobes - 4
Second Premolar
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These premolars have 2 or 3 cusps. The buccal
cusp is very large. If two lingual cusps are present,
the mesiolingual is the larger. Although the lingual
cusps are larger than on the first premolar, they are
afunctional and do not occlude with the maxillary
teeth. A second premolar has more secondary
anatomical features and more variation than any
other tooth except a third molar.
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The two-cusp forms a U- or H- groove
pattern. A mesiolingual groove is rare and is
poorly developed if present. The three-cusp
form has a lingual developmental groove
between the two lingual cusps and forms a Ygroove pattern. The single root is longer and
larger than that of a first premolar.
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Number of roots – 1
Number of pulp horns – 2 or 3
Number of cusps – 2 or 3
Number of developmental lobes - 4
First Molar
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The five cusps make these that largest mandibular
teeth. They are wider mesiodistally than
buccolingually. The crown converges lingually and
slightly distally. The three buccal cusps are
seperated by two buccal grooves. The two lingual
cusps are seperated by one lingual groove. These
three grooves converge to form a Y pattern. There
are two roots, a mesial and a distal, and three root
canals (the mesial root has two root canals).
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Number of roots – 2
Number of pulp horns – 5
Number of cusps – 5
Number of developmental lobes - 5
Second Molars
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These molars have four cusps of nearly equal size.
The crown is smaller in all dimensions and has less
lingual convergence. There is only one buccal
groove and one lingual groove, which join together
on the occlusal surface as they bisect the central
developmental groove. The groove pattern is
therefore a cross (+). The two roots are closer
together and incline slightly distally. There is one
root canal in the distal root. The mesial root can
have one or two root canals.
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Number of roots – 2
Number of pulp horns – 4
Number of cusps – 4
Number of developmental lobes - 4
Third Molars
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These are the most variable mandibular
teeth in form. They usually resemble the
mandibular second molars, with four cusps
and a shallower, smaller central fossa, with
more secondary and teriary grooves. A fivecusp form is not unusual. The two roots
(mesial and distal) and often fused and
inclined toward the distal side.
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Number of roots – 2 (fused)
Number of pulp horns – 4 or 5
Number of cusps – 4 or 5
Number of developmental lobes – 4 or 5