dental anatomy.ppt

Dental anatomy
Dr Adaruku kennedy
BDS(Muk)

Human Dentition
Introduction
Dental Anatomy Includes:
1- Nomenclature & terminology.
2- The external morphology and internal
composition of individual teeth.
3-How tooth form serves its function.
4- The relationship of teeth to each
other and to the jaw bones.

Dental Anatomy Nomenclature
The Jaws & Dental Arches

 A. The maxilla is two
bones forming
the upper jaw;
they are rigidly attached
to the skull.
 B. The mandible is
a horse-shoe
shaped bone which
articulates with the
skull by way of the
temporo-mandibular
joint the TMJ.
The Jaws and Dental Arches

Quadrants:
right & left quadrants
Maxillary right
and left.
Mandibular right
and left.
Right Left
Right Left
4 Quadrants

Functions of Teeth
1- Mastication:
teeth are designed to perform this function.
Incisors Canine Premolars Molars
Chisel like
Cutting or
incising
Wedge like
Cutting
and
tearing
At least
two
projections
(cusps).
Tearing and
Multiple
projections
(cusps)
Grinding

4- Growth of jaws:
The teeth play a role in the growth of the jaws in some
periods of life.
2- Appearance:
- Well arranged clean
teeth with proper
alignment give nice
appearance to the face. –
Teeth give support to the
facial expressions.
3- Speech:
for clear pronunciation and
production of sound.

Types of Teeth
Posterior Teeth
Anterior Teeth
for
cutting & tearing
food

Anterior Teeth - Upper
lateral Central
Incisors
Canine

Anterior Teeth - Lower
lateral - Central
Incisors
Canine

Premolars:
(in permanent only)
First premolar
&
Second premolar
Upper
Lower

Molars:
First & second
Upper
Lower
Wisdom tooth =
Third permanent molar

Types of Dentitions:
Primary & Permanent Dentition

Types of Dentitions:
I-Primary Dentition
Deciduous ,baby, milk
teeth:
a. Twenty ( 20)
primary teeth.
b. 10 in each arch
c. 5 in each quadrant
In function:
2 years  12 years

Mixed Dentition Period
6 years  12 years
Eruption
of
first
permanent
molar
Shedding
of
last
primary
molar

6 years  eruption of first permanent molar

12 years  Shedding of last primary molar

II-Permanent Dentition
In
function:
12 years
through
out
life

1.Palmer Notation System
2.Universal System
3.International FDI System
(two digit system)
Tooth Identification
Systems
Numbering or Coding Systems

1 - 8
1 1
1-Palmer Notation System
2 3
4
5
6
7
8
2
3
4
5
6
7
8
1 2
3
4
5
6
7
8
Right Left
for Permanent Teeth
8 - 1
8 - 1
1 - 8

The permanent teeth are numbered
from 1-8 on each side from the midline.
Upper right Upper left
8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8
8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8
Lower right Lower left
Horizontal and vertical lines = symbol for the quadrant
It represents the four quadrants of the dentition
as if you are facing the patient.
In upper right In upper left
In lower right In lower left

A
B
C
D
E
Palmer Notation System
for Primary Teeth
E-A
E-A
A-E
A-E

The deciduous teeth are lettered
from A-E on each side from the midline
Upper right Upper left
E D C B A A B C D E
E D C B A A B C D E
Lower right Lower left

2-The International Numbering System
“FDI” Federation Dentaire International
(the two digit system)
The teeth are designated by using two-digits:
a. The first digit of the code is located at the left side of
the number and indicates the quadrant:
In permanent dentition In deciduous dentition
U.R. 1 2 U.L. U.R. 5 6 U.L
L.R. 4 3 L. L. L.R. 8 7 L.L.

2-International
System
(Two Digit
System)
“FDI”
Federation Dentaire
International
11
12
13
14
15
16
17
18
21 22
23
24
25
26
27
28
31 32
33
34
35
36
37
38
41
42
43
44
45
46
47
48
1 2
3
4
For permanent Teeth
First Digit = quadrant

Permanent teeth
18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28
48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38
b- The second digit is located at the right side of the number
and indicates the number of the tooth in the quadrant.
The two digits should be pronounced separately.
Second Digit = Tooth number in the quadrant

For Primary Teeth
5 6
7
8
5 6
7
8
51
52
53
54
55
61
62
63
64
65
71 72
73
74
75
81
82
84
83
85
2-International
System
(Two Digit
System)
“FDI”
Federation Dentaire
International
2nd Digit =tooth number

Primary Teeth
55 54 53 52 51 61 62 63 64 65
85 84 83 82 81 71 72 73 74 75
Second Digit = Tooth number in the quadrant
5 6
7
8
For Primary Teeth

Universal
system
for
Permanent
Teeth

Universal
System
for Primary
Teeth

Macro & Micro-anatomy
of Teeth
crown
neck
root

Surrounding Bone:
Crypt  developing tooth
Socket  erupted tooth root

Anatomical Crown & Clinical Crown

Cont’
 Clinical crown –part of the crown that is visible in
the mouth
 Anatomical crown part of the crown up to the
level of cemento-enamel junction

Pulp Cavity
1-Coronal pulp:
•Pulp chamber
•Pulp horns
2-Radicular pulp:
•Root canal
•Apical foramen

2-Radicular pulp:
•Root canal
•Apical foramen
Pulp Cavity in Root

Surfaces of teeth are identified by the
relationship to
surrounding orofacial structures
Each tooth
has
Five
surfaces:
1.Facial
2.Lingual,
3.Mesial, and
4. Distal (proximal)
5.Functioning surf.
(Incisal) occlusal,

FACIAL SURFACE
any surface on the outside
(towards the face)
1.LABIAL is facial
surface of the
anterior teeth
(green),
2. BUCCAL is the
facial surface
of the
posterior teeth
(blue).

Inter-proximal
surfaces:
1.Facing towards the
midline: MESIAL.
2. Facing away from the
midline:  DISTAL
Surfaces in between two teeth:

LINGUAL
The surfaces facing the tongue
PALATAL
on the maxilla.
palatal

Functioning Surfaces:
chewing/biting surfaces of teeth :
OCCLUSAL: chewing surfaces of
posterior teeth
INCISAL: the anteriors’
biting surface

Line and Point Angles
Division into Thirds

Line angle:
It is formed by the junction
of two surfaces
and its name is derived
from both surfaces
Point angle:
It is formed by the junction
of three surfaces
and its name is derived
from these surfaces.
Line and Point Angles

Line Angles
of Posterior Teeth

Point Angles
Meeting of 3 surfaces

Anatomical Landmarks
of the Crown
Developmental data:
Lobe:
• It is one of the primary
centers of calcification and
growth formed during the
crown development.
• Each tooth begins to
develop from four lobes or
more.
•The pulp chamber has pulp
horns corresponding to
these lobes.

Maxillary molars
Mandibular molars

A- Crown Elevations:
They are three small
rounded projections
of enamel present in
the incisal third of
newly erupted
incisors
It is the bulge on
the cervical third
of lingual surface
of the crown in
anterior teeth
1-Mamelons 2-Cingulum 3-Cusps
They are pyramidal
projections on the
incisal portion of the
canine and on the
occlusal surfaces of the
premolars and molars

4-Tubercle
It is a small elevation produced by
excessive formation of enamel.
Tubercle is noticed at :
•the palatal surface of E & 6
•sometimes at the lingual surface of
incisors over the cingulum.
N.B. Tubercle differs from cusp , it is
formed of enamel only while cusp is
formed of pulp horn covered by dentin
and enamel.

Ridge or elevation
of enamel forming
the margin of the
surface of a tooth;
• on mesial /distal
margins of lingual
surfaces anterior
teeth.
• mesial & distal
margins of occlusal
surfaces posterior
teeth
5-Ridges
•Linear ridges:
Elevated portions
of tooth run in a
line named for
their location
•Cervical
•Incisal
•Labial
•Buccal
•Lingual
Marginal
Triangular
Linear
Transverse Ridge
Oblique Ridge

•Small , irregularly placed
auxiliary grooves.
•Branches from developmental grooves.
•They do not denote union of primary
lobes.
•The third molars followed by second
permanent molars are characterized by
high number of supplemental grooves.
B-Crown Depressions
•Lingual
fossa
•triangular
fossae
•Central
fossa
1-Developmental
grooves:
Shallow grooves that
separate cusps or primary
parts of teeth
Linear Depressions Irregular Depressions
1-Fossa
Depression or concavity
2- Supplemental
grooves:

3- Fissures
• Found in the bottom of
developmental grooves.
•Result from incomplete union of
the primary lobes.
•Represent a fault in enamel.
Linear Depressions Irregular Depressions
2- PITS:
•b- FAULTY PIT:
• Develop as a result
• of incomplete formation of
enamel.
• It is located at the end of
the buccal developmental
grooves of the lower molars or
palatal developmental
grooves of the upper molars.

Morphology of human teeth
Permanent teeth ..upper arch
Central incisiors(11,21)
Crown is broad and flat
Distal edge is more rounded
than the mesial edge.
Root is single and
conical,tapers towards the
apex

Cont.
Lateral incisors(12,22)
 Smaller than central incisors
 Single root with slight flattening
 Incisal edge more rounded distally
 Canines
 Single cusp in line with centre of the
tooth
 Well marked cingulum with marginal
ridges
 Has the largest root of any
tooth,single and flattened.

cont
First premolar(14,24)
 Has 2 cusps,buccal cusp larger
 Has 2 roots ,bifurcated halfway
 Has a groove in the enamel of the
mesial marginal ridge
Second premolars(15,25)
 Has two cusps,both at the same level
 Has one root grooved mesially and
distally,all roots have a tendency of
bending distally.

molars
Has three roots-palatal is the
largest,mesiobuccal root and
distobuccal root
 first molar is the largest tooth
in the maxilla.

Mandiblular teeth
Central incisors(41,31)
 Smallest tooth of the permanent
dentition
 Labial surface is flat incisally
 Root is single and flattened with distal
and mesial grooves
Lateral incisors(42,32)
 Similar to centrals but larger
 Incisal edge is wider and oblique
towards the distal

cont
Canines(43,33)
 Similar to upper canines but smaller
 Cusps and cingulum not so well developed as
in uppers.
 Single root ,ovoid in cross section.
First premolars(44,34)
 Smallest premolar tooth
 Small lingual cusp ,slopping buccal cusp.
 A ridge connects the buccal and lingual cusps
 Single root,conical in cross section.

Cont’
Second premolars(44,34)
Roots are more staut than for 1st
premolars
Single rooted
Molars(lower)
Larger
Have two roots – 1distal and 1
mesial
Roots have a tendency to curve

Deciduous teeth(maxilla)
Incisors and canines
 Smaller than their permanent
counterparts
 Mesio-distal diameter is greater than
their incisor- cervical diameter
First deciduous molar
 Has three cusps,2 buccal ,1 palatal
 3 roots mesiobuccal,distobuccal and
palatal.
 2nd deciduous molar is similar to the

differences
Deciduous teeth Permanent teeth
 More bulbous,pointed
cusps
 Whiter
 Large pulp chamber
 Roots of primary
molars are more
divergent
 Cemento-enamel
junction ends abruptly
 No premolars
 Less bulbous
 Less whiter
 Narrower pulp
chamber
 Roots of molars less
divergent compared
to their primary
counterparts
 CEJ ends gradually
 Premolars present

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