University of Palestine
College of Dentistry
Human Dentition I
Classification and Numbering System
Dr. Samir M. Ziara 
B.D.S. (Alexandria Univ.) 
D. D. P. H. Royal Collage of Surgeon (London) 
M. Sc. P. H. Al-Quds Univ. 
Diploma of H. Administration 
Surface Anatomy of
Permanent Teeth
Surface Anatomy of
Permanent Teeth
I, for incisor
C, for canine
I
C
P, for premolar
M
M, for molar
P
M
P
I
Anterior teeth
They are divided into:
Incisors
And
Canines
Incisors
There are four maxillary incisors
and four mandibular incisors.
♥ Two central incisors
contact with each other in the
midline (mesially) and with
the lateral incisors distally.
♥ Two lateral incisors contact
with the central incisor mesially
and with the canine distally.
For easy teeth description
We have to speak about :
• Function (mastication (incising), esthetic,
speaking).
• Chronology.
• Number of lobes (four lobes 3 labially and 1
lingually).
• Geometric outline of the crown.
• Outlines of the crown and root.
• Surface anatomy of the crown and root.
• Pulp cavity.
Chronology:
•Enamel organ appearance.
•Beginning of calcification.
•Crown completed.
•Eruption.
•Root completed.
All teeth have 5 aspects
1
Facial
Lingual
Incisal
Mesial
Distal
2
Labial
Lingual
Mesial
Incisal
Distal
1
Labial
Lingual
Incisal
Mesial
Distal
2
Labial
Lingual
Incisal
Mesial
Distal
Geometric outline of the crown
Facial and lingual aspects have
trapezoid out line.
Smallest uneven side cervically.
Facial and lingual outlines of
the crown
As mentioned before It’s Trapezoid and
is formed of
Cervical outline (convex root
wise)
Distal outline
(more convex)
Mesial outline
(convex)
Sharp mesioincisal
angle
Rounded
distoincisal angle
Incisal (straight and may
have mamelons)
When?
☺You have to note that 2
has two rounded angles but
the distal angle is more.
☺1
has two sharp
angles and straight
out lines mesially
and distally.
D
M
Outlines of the root
• The mesial and distal outline of the
root tapered to a pointed apex
The apex directed distally except the
1 it’s centralized on the long axis so
extraction could be done by rotation
movement
•
Note: the apex of 1 is blunt.
Surface anatomy of the crown and root.
Labial aspect
Elevations:
• The crown surface is smooth and
convex with maximum convexity at
the cervical third (cervical ridge)
Depressions:
•Shallow developmental grooves could
be seen separating mamelons.
•The root surface is smooth and convex
Lingual aspect
Elevations:
•Marginal ridges (mesial and
cingulum
distal)
•Cingulum (cervically)
•Incisal ridge
Depressions:
Lingual fossa
Incisal ridge
Marginal
ridges
Note:
•All elevations are more
developed in upper teeth
than in lower teeth.
•So the fossae appear
shallower in the lower teeth.
•Lingual pit could be
found in the 2 and should
notice that all elevations
are well developed than 1
☺You have to notice that the lingual surface
of all teeth is smaller in size than the labial
due to the lingual convergence.
This convergence of the
teeth is to accommodate
the larger arch size
facially than lingually
Can you tell
*which tooth
*which aspect
*which surface anatomical
landmark
1 , labial aspest, cervical ridge.
2, lingual aspect, lingual pit.
2 , labial aspect, cervical ridge.
2, lingual aspect, cingulum,
M&D marginal ridges
Geometric outline of the crown
Proximal (mesial and distal)
aspects have triangular outline
Base cervically.
Note: the incisal
ridge of 1 &2
inclined lingually.
Why?
Apex
incisally.
Mesial and distal Outlines
It’s Triangular and formed of
•Labial outline: convex with maximum
convixity at the cervical third which
represent …….
•Lingual outline:
convex incisally which represent…….
Concave at the middle which represent…
Convex cervically which represent………
•Cervical outline: Curves incisally.
Note:
•The convexity of labial and lingual
outlines are well developed in the
upper teeth than lower teeth. Why?
•The curvature of cervical lines in all
teeth distally is less than mesially. The
height of curvature decreased also
from upper teeth to lower teeth
Outlines of the root
Upper incisors:
The outlines tapered from the
cervical line to a blunt rounded
apex
Lower incisors:
The outline are nearly straight
from the cervical line to the
middle third then tapered to a
pointed apex
Surface anatomy of the crown and root.
The crowns have smooth convex proximal surfaces.
The contact areas present in the
incisal third.
Mesially, near the mesioincisal
angle.
distally, near the junction of
incisal and middle thirds.
Note: the contact areas mesially and distally
are near to each other but still distal contact
area present more cervically.
Roots
They have convex smooth
surfaces except lower incisors
have longitudinal developmental
depression which is deeper
distally than mesially.
Incisal aspect
Outline and surface anatomy
Upper incisors:
The outline is triangular in shape.
The base is placed labially and apex
lingually.
The mesiodistal dimension (width)
is greater than the labiolingual
dimention (thickness).
Note:
The crown is tapered lingually.
•The elevations and depressions in the crown
lingually and labially appeared in this aspect.
Lower incisors:
The outline is diamond in shape.
The labiolingual dimension Is greater
than the mesiodistal dimension.
•The incisal ridge of 2 tilted distally that allows the
tooth to follow the dental arch curvature.
Pulp cavity.
Pulp cavity is formed of:
Pulp chamber that is present in the crown.
Its outline follows the outline of the crown.
In young teeth, it has pulp horns related to
each mamelon
Root canal that present in the root and
follow its outline. The number of root canals
in incisors is only one. The root canal ends
in an apical foramen
Identify the tooth, the aspects and tell FOUR
differences between the lateral and central incisor.
Answer
A- Upper P. central incisor.
B- Upper P.lateral incisor
Lingual aspect
1- Size.
2- The elevations and
depressions
3- The incisal angles.
A
4- The root.
B
Identify the tooth, the aspect and
the anatomical landmark.
2, lingual aspect, long mesial
marginal ridge, short distal
marginal ridge.
A
1, mesial aspect, contact
area, cervical line.
A is for 2, incisal aspect,
distally tilted cingulum.
B is for 1 , incisal aspect,
lingual fossa.
B