1. TRAIT CATEGORIES HELPFUL IN
DESCRIBING TOOTH
DIFFERENCES

2. DEFINITIONS
 A trait is distinguishing characteristic,
quality, peculiarity or attribute.
 Set Traits
 Arch Traits
 Class Traits
 Type Traits

3.  SET TRAITS (Dentition traits)
 Distinguish teeth in the primary
(deciduous) from secondary
(permanent) dentition.
 ARCH TRAITS
 Distinguish maxillary from
mandibular teeth.

4.  CLASS TRAITS
 Distinguish the four categories (or
classes) of teeth: namely incisors,
canines, premolars and molars.
 Example: incisors have crowns
compressed labiolingually for efficient
cutting; canines have single pointed
cusps for piercing food; premolars have
two or three cusps for shearing and
grinding; molars have 3-5 somewhat
flattened cusps for grinding.

5.  TYPE TRAITS
 Differentiate teeth within one class (such
as differences between central and
lateral incisors, or between 1st and 2nd
premolar or between 1st, 2nd, and 3rd
molars).

6. DIFFERENCES BETWEEN MAXILLARY AND
MANDIBULAR INCISORS
LABIAL VIEW
Wider, less symmetrical points. Long, narrow, symmetrical crown.
Mesial contacts are more incisally Mesial and distal contacts are at
located than distal contacts. about the same level.
Mesial and distal incisal angles are
More rounded distoincisal angles.
sharp.
Common labial depressions. Less frequent labial depressions.
More cervically located contacts.
Contacts very near incisal edge
Level of mesial and distal contact
(both medial and distal).
vary.

7. LINGUAL VIEW
Lingual smooth, almost no
Pronounced marginal ridges.
marginal ridges.
Deeper lingual fossa. Shallow lingual fossa.
Sometimes lingual pits. No pits.
Larger cingulum. Smaller cingulum.
Central almost perfectly
Central Incisor has cingulum to
symmetrical (Lateral has
distal.
cingulum to distal).

8. PROXIMAL VIEW
Incisal edge labial to root Incisal edge on or lingual to
access. root axis lines.
Elevated cingulum. Small cingulum.
Roots noticeably wider
Roots narrower, specially in facio-lingually (with
apical third. depressions on both sides
of roots).

9. INCISAL VIEW
Crowns wider facio-
Crowns wider mesio-
lingually than mesio-
distally than facio-lingually.
distally.
Incisal edge labial to mid- Incisal edge is lingual to or
root axis. centered on mid-root axis.
Central cingulum is to Central cingulum is
distal. centered.
Lateral cingulum is Lateral cingulum is to
centered. distal.

10. INCISAL VIEW
(cont.)
Lateral has almost round Lateral crown is oblong
crown outline. facio-lingually.
Central has more triangular Central crown is oblong
crown outline. facio-lingually.
Lateral and central are
Lateral is convex labially
nearly flat labially near
near incisors.
incisal.

11. DIFFERENCES BETWEEN MAXILLARY
CENTRAL AND LATERAL INCISORS
LABIAL VIEW
Smaller crown tip distally at
Larger crown, wider cervically.
cervix.
More symmetrical. Less symmetrical.
Mesial Incisal angle is 90
Rounded and acute angle.
degrees.
Mesial contact near incisal Distal contact near middle third.
Root is wide cervically, tapering
Longer and narrower root.
to blunt apex.
Less root apex bend to distal. Root tip often bend to distal.

12. LINGUAL VIEW
Large shallow lingual fossa. Deep but small fossa.
Cingulum distally positioned. Cingulum is centered.
Incisal edge outline curves less Rounded incisal edge slopes up
mesio-distally (is flatter) distally.
Shorter distance than mesio- Mesio-lingual ridge is straight
lingual marginal ridge. with distal curve.
Less frequent lingual pits. Common lingual pits.

13. PROXIMAL VIEW
Slightly less cervical line
Greater cervical line curve.
curve.
Evenly tapered root with
Root outlines more convex.
mesial side.
Slightly shallower lingual
Deeper lingual fossa outline.
fossa.

14. INCISAL VIEW
Crown noticeably wider mesio- Crown size mesio-distally and
distally. facio-lingually almost the same.
Crown outline roughly triangular. Crown outline round or oval.
Incisal ridge curves mesio- Shorter incisal ridge is straighter
distally. mesio-distally.
Cingulum is off centered to
Cingulum is centered.
distal.
Labial developmental
Sometimes labial depressions.
depressions.

15. DIFFERENCES BETWEEN RIGHT & LEFT
MAXILLARY INCISORS
LABIAL VIEW
Flat mesial but rounded distal Asymmetrical crown outline,
crown outline. shorter on distal.
Mesio-incisal angle is 90
Acute mesio-incisal angle.
degrees.
Slightly rounded disto-incisal More rounded disto-incisal
angle. angle.
Distal contact is much more
Distal contact more cervical.
cervical.

16. LINGUAL VIEW
Same as labial. Same as labial.
Long and straight mesio-
Cingulum towards distal.
lingual ridge.
Longer mesio-lingual Short and curved disto-
marginal ridge. lingual ridge.

17. PROXIMAL VIEW
Larger cervical line curve on Larger cervical line curve on
mesial than distal. mesial than distal.
Flat mesial side of root with
depression.
INCISAL VIEW
Shorter curved disto-lingual
Cingulum towards distal.
marginal ridge.
Longer mesio-lingual marginal Mesial crown outline flatter
ridge. than distal on lingual taper.

18. THANK YOU