Human Human DentitionDentition

IntroductionIntroductionDental 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 NomenclatureThe Jaws & Dental ArchesThe 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 The Jaws and Dental Arches The Jaws and Dental Arches The Jaws and Dental Arches

Quadrants:right & left quadrants Maxillary rightMaxillary right and left.and left.

Mandibular Mandibular rightright and left.and left.

Right Left

Right Left44 QuadrantsQuadrants

Functions of Functions of TeethTeeth1- 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 grinding

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 TeethTypes of Teeth

Types of Types of TeethTeeth

Posterior TeethPosterior Teeth

Anterior TeethAnterior Teethfor for

cutting & tearing cutting & tearing foodfood

Anterior TeethAnterior Teeth- - UpperUpper

lateral Centrallateral Central IncisorsIncisors

CanineCanine

Anterior TeethAnterior Teeth- - Lower Lower

lateral - Centrallateral - Central IncisorsIncisors

CanineCanine

PremolarsPremolars::(in permanent (in permanent only)only)

First premolar First premolar & &

Second premolarSecond premolar

UpperUpper

LowerLower

Molars:Molars:

First & second First & second

UpperUpper

LowerLowerWisdom tooth =Third permanent molar

Types of Dentitions:Types of Dentitions:Primary & Permanent Primary & Permanent

DentitionDentition

Types of Dentitions:Types of Dentitions:I-Primary DentitionI-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

I-Primary I-Primary DentitionDentition

Mixed Dentition Mixed Dentition PeriodPeriod

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 DentitionII-Permanent Dentition

In function:

12 years

through out life

Permanent Permanent TeethTeeth

1.1.Palmer Notation SystemPalmer Notation System

2.2.Universal SystemUniversal System

3.3.International FDI SystemInternational FDI System (two digit system)(two digit system)

Tooth Identification Tooth Identification SystemsSystems

Numbering or Coding SystemsNumbering or Coding Systems

1 - 81 - 8

1 1

1-Palmer Notation System1-Palmer Notation System

2 34

5

6

7

8

234

5

6

7

8

1 23

45

6

7

8

Right Leftfor Permanent Teethfor Permanent Teeth

8 - 18 - 1

8 - 18 - 1

1 - 81 - 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

AB

C

D

E

Palmer Notation SystemPalmer Notation Systemfor Primary Teethfor Primary Teeth

E-AE-A

E-AE-A

A-EA-E

A-EA-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

Palmer Notation SystemPalmer Notation System

2-The International Numbering System

“FDI”“FDI” Federation Dentaire InternationalFederation 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 In permanent dentition In deciduous dentitiondentition

U.R. 1 2 U.L. U.R. 5 6

U.L L.R. 4 3 L. L. L.R. 8 7

L.L.

2-2-International International System System(Two Digit (Two Digit System)System) “FDI”“FDI” Federation Federation Dentaire Dentaire International International

1112131415

1617

18

21 222324

25262728

31 323334

35

36

37

38

414243

444546

47

48

1 2

34

For permanent TeethFor permanent Teeth

First Digit = quadrantFirst 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 quadrantSecond Digit = Tooth number in the quadrant

For Primary TeethFor Primary Teeth

5 6

78

First Digit = quadrantFirst Digit = quadrant 5 6

78

5152

53

54

55

6162

63

64

65

71 7273

74

75

8182

84

83

85

2-2-International International System System(Two Digit (Two Digit System)System) “FDI”“FDI” Federation Federation Dentaire Dentaire International International

First Digit = quadrantFirst Digit = quadrant

Primary Teeth

55 54 53 52 51 61 62 63 64 65

85 84 83 82 81 71 72 73 74 75

First Digit = quadrantFirst Digit = quadrant

Second Digit = Tooth number in the quadrantSecond Digit = Tooth number in the quadrant

5 6

78

For Primary TeethFor Primary Teeth

Universal Universal system system

for for PermanePermanent Teethnt Teeth

Universal Universal System System

for Primary for Primary TeethTeeth

Macro & Micro-anatomy Macro & Micro-anatomy

of Teethof Teethcrown

neckroot

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

rootroot

Anatomical Crown & Clinical Anatomical Crown & Clinical CrownCrown

Single-rooted Multi-Single-rooted Multi-rootedrooted

Micro-anatomy of TeethMicro-anatomy of Teeth

Pulp CavityPulp 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 Pulp Cavity in RootRoot

Surfaces Surfaces of of Teeth Teeth

Surfaces of teeth are identified Surfaces of teeth are identified by the relationship toby the relationship to surrounding orofacial surrounding orofacial

structuresstructuresEach Each

tooth has tooth has FiveFive

surfaces:surfaces:

1.1.Facial Facial 2.2.Lingual, Lingual, 3.3.Mesial, andMesial, and4.4. Distal (proximal)Distal (proximal)5.5.Functioning surf.Functioning surf. (Incisal) occlusal, (Incisal) occlusal,

FACIAL SURFACEFACIAL SURFACE any surface on the outside any surface on the outside

(towards the face) (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 Inter-proximal surfaces:surfaces:

1.Facing towards the midline: MESIAL.

2. Facing away from the midline: DISTAL

Surfaces in between two Surfaces in between two teeth:teeth:

LINGUALLINGUAL The surfaces facing the tongueThe surfaces facing the tongue

PALATALPALATAL on the maxilla. on the maxilla.

palatal

Functioning Surfaces:Functioning Surfaces:chewing/biting surfaces of teeth chewing/biting surfaces of teeth

::

OCCLUSAL:OCCLUSAL: chewing surfaces of chewing surfaces of posterior teethposterior teeth

INCISAL:INCISAL: the anteriors’ the anteriors’ biting surface biting surface

Line and Point AnglesDivision 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 AnglesLine and Point Angles

Line Anglesof Anterior Teeth

Line AnglesLine Anglesof Posterior Teethof Posterior Teeth

Point AnglesPoint AnglesMeeting of 3 surfacesMeeting of 3 surfaces

Division into Thirds

Anatomical Anatomical Landmarks Landmarks of the Crownof the CrownDevelopmental data:Developmental data:

LobeLobe::• 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.

Anterior teeth

premolars

Maxillary molarsMaxillary molars

Mandibular molars

A- Crown Elevations:A- Crown Elevations:A- Crown Elevations: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-Mamelons1-Mamelons1-Mamelons1-Mamelons 2-Cingulum2-Cingulum2-Cingulum2-Cingulum 3-Cusps 3-Cusps 3-Cusps 3-Cusps

They are pyramidal projections on the

incisal portion of the canine and on the

occlusal surfaces of the premolars and

molars

4-Tubercle4-Tubercle4-Tubercle4-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-Ridges5-Ridges5-Ridges5-Ridges

•Linear ridges: Elevated portions of tooth run in aline named for their location

•Cervical•Incisal•Labial •Buccal •Lingual

MarginalMarginalMarginalMarginal

TriangularTriangularTriangularTriangularLinearLinearLinearLinear

Transverse RidgeTransverse Ridge

Oblique RidgeOblique 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 B-Crown DepressionsDepressionsB-Crown B-Crown DepressionsDepressions

•Lingual fossa

•triangular fossae

•Central fossa

1-Developmental 1-Developmental grooves:grooves:Shallow grooves thatseparate cusps or primaryparts of teeth

Linear DepressionsLinear DepressionsLinear DepressionsLinear Depressions Irregular DepressionsIrregular DepressionsIrregular DepressionsIrregular Depressions

1-Fossa1-FossaDepression or concavity

2- Supplemental 2- Supplemental grooves:grooves:

3- Fissures3- Fissures• Found in the bottom of developmental grooves. •Result from incomplete union of the primary lobes. •Represent a fault in enamel.

Linear DepressionsLinear DepressionsLinear DepressionsLinear Depressions Irregular DepressionsIrregular DepressionsIrregular DepressionsIrregular Depressions

2- PITS: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.