Oral Anatomy: Tooth identification

Chapter 10
Tooth Identification
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Copyright © 2003 by Mosby, Inc., an affiliate of Elsevier Inc.
Previous editions copyrighted 1977, 1982, 1986, 1990, 1994, 1998.

1. Curvature of the CEJ is about 1 mm less on
the distal surface of the tooth than on the
mesial.
2. If the tooth roots curve, they usually curve
distally, especially at the apex of the root.
3. The distal incisal edges of anterior teeth are
more rounded than the mesial incisal edges.
General Rules of Tooth Identification
2

4. Mandibular anterior teeth tend to wear on the
labial incisal edges; maxillary teeth wear on the
lingual incisal edges.
5. Permanent molars are generally smaller in
height and have fewer cusps the more posterior
they are positioned.
6. Permanent molars tend to have more
secondary and tertiary anatomy the more
posterior they are positioned.
3

7. Roots of molars tend to be shorter and closer
together the more posterior the molars are
positioned, and the roots are often fused into
one.
a. First molars have the widest and longest roots of
all molars.
8. The more posterior the molars are positioned,
the more variation of anatomy is evident.
4

Incisors
5
Incisors
 Incisal two thirds
appear flattened on
labial and lingual sides.
 Incisal edge, not a
cusp.

Incisors
6
Maxillary
 Crown wider
mesiodistally than
faciolingually.
 Root has triangular
cross section; broader
on facial side.

Incisors
7
Maxillary Central
 Greater crown-to-root
ratio than lateral
incisors.
 Mesioincisal angle
sharp (90 degrees).
 Contact area in incisal
third.
 Broad, smooth lingual
fossa with cingulum.

Incisors
Maxillary Lateral
 Lesser crown-to-root
ratio than central
incisors.
 Mesioincisal angle
rounded.
 Contact area at junction
of middle and incisal
thirds.
8

Incisors
Maxillary Lateral (Cont.)
 Small cingulum; often
with a lingual pit.
9

Incisors
Maxillary Lateral: Right-Left
 Mesioincisal angles more square than distoincisal
angles.
 Crest of cervical line more often displaced toward
distal from labial or lingual view.
10

Incisors
Maxillary Lateral:
Right-Left (Cont.)
 Mesiocervical line
curves more incisally
than distocervical line.
11

Incisors
Mandibular
 Smaller than maxillary
central or lateral incisor.
 Crown wider
faciolingually than
mesiodistally.
 Root with oval cross
section.
12

Incisors
Mandibular (Cont.)
 Incisal edge wears on labial surface.
 Incisal edge angled toward the lingual side.
13

Incisors
Mandibular Central
 Incisal view: incisal edge perpendicular to
faciolingual axis of tooth.
 Mesial and distal lobes appear identical.
14

Mandibular Central: Right-Left
 Cervical line curves more incisally on mesial than on
distal surface.
 Height of curvature of cervical line on mesial greater
than on distal surface.
 Root tip may have slight distal curve.
 Incisal edge worn wider on distal surface.
Incisors
15

Incisors
Mandibular Lateral
 Incisal view: distoincisal edge angled toward lingual
side.
 Distal lobe appears larger than mesial lobe.
16

Mandibular Lateral: Right-Left
distal surface.
 Incisal view: distal half of incisal edge rotated toward
lingual side.
 Incisal edge worn wider and longer on distal surface.
Incisors
17

Canines
 Single conical cusp with well-developed mesiofacial
lobe.
 Lingual cusp ridge from cusp tip to lingual fossa.
Canines
18

Canines
Maxillary Canines
 Lingual surface has
well-developed
marginal ridges,
cingulum, and fossa.
19

Canines
Maxillary Canines
(Cont.)
 Larger crown than
incisors and lower
canines; more distal
convexity.
 Cusp tip directly
midcenter over root.
20

Canines
Maxillary Canines: Right-Left
distal.
 Incisal view: distofacial lobe elongated.
21

Canines
Maxillary Canines: Right-Left (Cont.)
 Facial view: distal surface rounded.
 Contact area located more cervically.
22

Canines
Mandibular Canines
 Lingual surface almost
smooth with poorly
developed ridges,
cingulum, and fossa.
 Narrower mesiodistal
width than maxillary.
23

Canines
Mandibular Canines (Cont.)
 More wear on facial (labial) surface when compared
with maxillary canine.
24

Premolars
 At least two cusps, one a single facial cusp, with
one or two lingual cusps.
Premolars
25

Premolars
Maxillary Premolars
 Two major cusps;
buccal and lingual.
 Wider faciolingually
than mesiodistally.
 Proximal view: facial
and lingual cusps
nearly same height;
located over root trunk.
26

Premolars
Maxillary First Premolar
 Facial cusp slightly
longer than lingual
cusp.
27

Maxillary First Premolar (Cont.)
 Often has two roots; buccal and lingual.
 Occlusal surface has well-developed central groove,
with little supplemental grooving.
 Mesial surface has depression above contact area
below cervical line and extending onto root.
Maxillary First Premolar: Right-Left
 Mesial marginal groove.
 Cervical line on mesial curves more occlusally than
on distal surface.
Premolars
28

Premolars
Maxillary First Premolar: Occlusal View
 Mesiofacial cusp ridge forms 90-degree angle with
mesial marginal ridge.
 Distofacial cusp ridge forms rounded angle with
distal marginal ridge.
29

Premolars
Maxillary Second
Premolar
 Facial and lingual
cusps are nearly same
height.
 Usually single rooted.
30

Premolars
Maxillary Second Premolar (Cont.)
 Short central groove; numerous supplemental
grooves.
 No depression on mesial or distal crown surfaces.
 Right-left: lingual cusp displaced toward mesial.
31

Mandibular Premolar
 Prominent facial cusp with one or two much smaller
lingual cusps.
 Nearly equal faciolingual and mesiodistal widths.
Premolars
32

Premolars
Mandibular Premolar
(Cont.)
 Proximal view: facial
cusp much larger with
tip at or near midaxis of
root; lingual cusp(s)
extend lingually past
lingual border of root.
33

Premolars
Mandibular First
Premolar
 Proximal view: occlusal
surface tilted toward
lingual side.
 Cervical line on mesial
curves more occlusally
than on distal.
34

Premolars
Mandibular First Premolar (Cont.)
 Occlusal view: oval outline with strong transverse
ridge and no central pit.
35

Premolars
Mandibular First Premolar: Right-Left
 Depression or groove where mesial marginal ridge
joins lingual cusp ridge.
 Distal marginal ridge more prominent.
36

Premolars
Mandibular Second Premolar
 Occlusal view: pentagonal outline, with a central pit
and no transverse ridge.
37

Premolars
Mandibular Second
Premolar (Cont.)
 Proximal view: occlusal
surface less lingually
tilted.
 May have two lingual
cusps.
38

Mandibular Second Premolar: Right-Left
 Proximal view: more of occlusal surface visible from
distal than from mesial because of distal inclination
of crown-to-root axis.
Premolars
39

Molars
 Three to five cusps, with at least two facial.
Maxillary Molars
 Crowns wider faciolingually than mesiodistally.
 Three roots: two on facial and one on lingual side.
Molars
40

Molars
Maxillary First Molar
 Occlusal view: strong oblique ridge less likely to be
crossed by a groove.
41

Molars
Maxillary First Molar
(Cont.)
 Three roots widely
separated.
 Often fifth cusp
(Carabelli’s) on
mesiolingual cusp.
42

Molars
Maxillary Second Molar
 Occlusal view: smaller
oblique ridge usually
interrupted by a groove.
 Right-left: mesiolingual
cusp larger than
distolingual cusp.
43

Molars
Maxillary Second Molar (Cont.)
 Roots closer together.
 No fifth cusp.
 Distolingual cusp smaller than on
first molar.
44

Molars
Maxillary Third Molar
 Distolingual cusp
progressively smaller or
missing entirely.
 Roots either fused or
very close together and
much shorter.
45

Molars
Maxillary Third Molar
(Cont.)
 No oblique ridge.
 Right-left: distofacial
cusp much shorter than
other molars.
 Roots curved distally.
46

Mandibular Molars
 Crowns wider mesiodistally than faciolingually.
 Two roots: one mesial and one distal.
Molars
47

Molars
Mandibular First Molar
 Three facial cusps and
two facial grooves.
 Roots widely separated
and relatively vertical.
48

Molars
Mandibular First Molar:
Right-Left
 Distal cusp is smallest
facial cusp.
49

Molars
Mandibular Second
Molar
 Only two facial cusps
and one facial groove.
 Roots close together.
50

Molars
Mandibular Second
Molar (Cont.)
 Occlusal groove well
defined but travels
straight mesial to distal
and forms a cross with
facial and lingual
grooves.
51

Molars
Mandibular Second
Molar: Right-Left
 Buccal height of
contour in cervical third;
lingual height of
contour in middle third.
52

Molars
Mandibular Third Molar
 Secondary and tertiary anatomy.
 Short roots, often fused and curved distally.
 Right-left: crown tapers distally; wider faciolingually
on mesial than on distal surface.
53

Oral Anatomy: Tooth identification

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