Dental Anatomy

Dental Anatomy

Course Identification and General Information:

1. Course title and code: Dental anatomy /code: 190122006 2. Contact hours: (6 / week) 3. Course director:Dr/ Hoda Fansa: hafansa@uqu.edu.sa. Assistant professor of oral biology.

Definition:Dental anatomy is a course that study the gross structure of the oral cavity and teeth without using the microscope.

Dr. Sherif HassanAssociate Professor

1. Dental Anatomy.2. Oral Biology.3. Forensic Dentistry.

Requirements

Introduction To Dental

Anatomy

PALATINE TONSILS

GINGIVALABIAL FRENUM

UVULA

TONGUE

TEETH

CHEEK

FLOOR OF THE

MOUTH

PALATEROOF OF

THE MOUTH

THE ORAL CAVITY.

The teeth are arranged in the mouth in two arches termed dental arches.1- Upper dental arch:Carry the upper teeth and termed maxillary arch.2- Lower dental arch: Carry the lower teeth and termed mandibular arch.

Imaginary vertical line divide the body into

two similar halves (right half and left half).The midline divide the dental arch into two

similar halves, and So Divide the oral cavity

into four similar quadrants.

1. Upper right. 2. upper left.

3. Lower right. 4. lower left.

midline

DENTAL ARCH

Functions Of Teeth

1. Appearance. 3. Speaking. 2. Eating.

Responsibilities towards your teeth.

1. Clean. 2. Discover.

Types Of Dentition

The deciduous teeth begin to erupt at about 6

month of age and completed at about 2 -2.5

years of age.Number of Deciduous Teeth:

The oral cavity of children before 6 years of

age contain 20 deciduous teeth, 10 in the

maxilla and 10 in the mandible.Terminology of Deciduous Teeth:

1.Temporary Teeth.

2.Primary Teeth.

3.Milky Teeth.

4.Baby Teeth.

Deciduous Dentition

Deciduous Incisors ( I ) :Two in each quadrant:

1.Central incisor is close to midline.

2.Lateral incisor next to central incisor.

3. Deciduous Canine ( C ):Next to lateral incisor.

Deciduous canine is the corner of the

mouth.

Deciduous Molars ( M ): The last two teeth in each quadrant.

4. First deciduous molar: next to canine.

5. Second deciduous molar: last one.

Quadrant of Deciduous Dentition

Dental Formula of Deciduous Teeth.

Eruption time: The first permanent tooth begin to erupt is first permanent

molar which erupt at about 6 years of age. The deciduous teeth are shedded one by one and replaced by

the permanent. Successor. Until all deciduous teeth will be shedded at about 12 years of

age. at this time, all teeth in the oral cavity are permanent.

So This stage is termed Permanent Dentition. Number of permanent Teeth:The oral cavity contain 32 permanent teeth, 16 in maxilla and 16 in mandible.

Permanent Incisors ( I ) :1. Permanent central incisor: close to midline.

2. Permanent lateral incisor: distal to central incisor.

Permanent Canine ( C ):3. Permanent canine is found distal to incisors.

Premolars ( P ):4. First Premolar: distal to canine.

5. Second Premolar: distal to first premolar .

Permanent Molars ( M ): The last three teeth in each quadrant.

6. First Permanent Molar: is distal to premolars.

7. Second Permanent Molar is distal to first permanent molar.

8. Third Molar is the last tooth in the oral cavity.

Quadrant of Permanent Dentition

Permanent SuccessorsPermanent Successors: Permanent Successors are teeth replace the deciduous one. Deciduous incisors are replaced by permanenet incisors. Deciduous canine is replaqced by permanent canine. 1st deciduous molar is replaced by 1st premolar. The 2nd deciduous molar is replaced by 2nd premolar. The permanent molars not have deciduous predecessors and Not Termed Successor.

Definition: Mixed dentition means that

the oral cavity contain both permanent and deciduous teeth .

This stage begin from eruption of the first permanent tooth which is first permanent molar at 6 years and ended at shedding of the last deciduous tooth which is second deciduous molar at 12 years of age.

Anterior Teeth: • Anterior Teeth is the teeth seen by the viewer.

• Anterior teeth are bounded by the angles of the lip.• Anterior teeth is the incisors and canine.

• Incisors act for cutting of foods, while canine for tearing of foods.Posterior Teeth:

• posterior teeth are premolars and molars .

Posterior teeth Anterior teeth

Crown

Neck

Root

Crown: • Crown is the part of the tooth that seen in the

oral cavity.• Crown is covered by enamel.

Anatomical and Clinical Crown:• Anatomical crown is the crown that seen in the

oral cavity from tip to cervical line (neck of the tooth).

• Clinical crown is the crown seen in the oral cavity by the dentist and may include part of the root.

Root • Root is the part of the tooth that immersed within

the jaw bone and not seen by the viewer.• Root is covered by cementum.

Cervical line: • Cervical line is the line of meeting of crown and

root.• Cervical line is termed:

1. Neck of the tooth.2. Cementoenamel junction (CEJ).

1.Single rooted teeth: Anterior teeth.

Premolars except maxillary first premolar. 2. Two rooted teeth:

Maxillary first premolar.Mandibular molars.3. Three rooted teeth: Maxillary molars.

Enamel

Dentin

Pulp

Cementum

Enamel: • Enamel is the hard tissue that cover the crown.• Enamel is the hardest tissue allover the body. Cementum: • Cementum is the hard tissue that cover the root.Dentin: • Dentin is the hard tissue that form the main bulk of the tooth.• Dentin is covered by enamel at crown and by cementum at root.• Dentin surround a central cavity within the tooth termed pulp.

Pulp:• The dental pulp is a loose delicate connective tissue occupying the cavity in the center of tooth and surrounded by dentin.

Anatomy of the pulp cavity:1- Pulp chamber: found within the crown.

2- Root canals: found within the root.

3- Apical foramen: opening of the tooth in which blood

vessels and nerves enter the tooth.

Anatomy of the pulp tissue: 1. Coronal pulp: found within the pulp

chamber.Boundaries: Coronal pulp has six surfaces, buccal, lingual,

mesial, distal, roof, and floor.

# Pulp horn: parts of the coronal pulp extend from the

roof under the cusp or mamelons.

Radicular pulp

Coronal pulp

Pulp Horn

2. Radicular pulp: found within the root canal- The size of radicular pulp decreases apically as the root canal become narrower.

1-Labial surface →That surface faced toward the lip.2-Lingual surface →That surface faced toward the tongue.3-Mesial Surface →That surface faced toward the midline.4-Distal surface →That surface faced away from midline.5-Incisal surface → Incisal ridge = Incisal edge. → The functioning surface of the crown. → Faced toward the apposing teeth.

1-Buccal surface → That surface faced toward the check.

2-Lingual surface → That surface faced toward the tongue.

3-Mesial surface → That surface faced toward the midline.

4-Distal surface → That surface faced away from midline.

5-Occlusal surface → That functioning surface of the crown

→ Faced toward the opposing teeth.

Classification Of Anterior Teeth Into Thirds

Labial and lingual Surfaces: is classified horizontally into three thirds:

1. Incisal Third. 2. Middle Third. 3. Cervical Third. Labial and lingual Surfaces: is classified longitudinally into three thirds:

1. Mesial Third. 2. Middle Third. 3. Distal Third. Proximal Surfaces: is classified horizontally into three thirds:

1. Incisal Third. 2. Middle Third. 3. Cervical Third. Proximal Surfaces: is classified longitudinally into three thirds: 1.

Labial Third. 2. Middle Third. 3. Lingual Third. Root of Anterior Teeth: is classified horizontally only into three thirds:

1. Cervical Third. 2. Middle Third. 3. Apical Third.

Classification Of Posterior Teeth Into Thirds

Buccal and lingual Surfaces: is classified horizontally into three thirds:

1. Occlusal Third. 2. Middle Third. 3. Cervical Third. Buccal and lingual Surfaces: is classified longitudinally into three thirds:

1. Mesial Third. 2. Middle Third. 3. Distal Third. Proximal Surfaces: is classified horizontally into three thirds:

1. Occlusal Third. 2. Middle Third. 3. Cervical Third. Proximal Surfaces: is classified longitudinally into three thirds: 1.

Buccal Third. 2. Middle Third. 3. Lingual Third. Root of Posterior Teeth: is classified horizontally only into three thirds:

1. Cervical Third. 2. Middle Third. 3. Apical Third.

Line angles Of Teeth

Definition:

Line angle is the line of meeting of two adjacent surfaces in tooth.

Line angles af anterior teeth:

Six in number: (IMP)

1.Mesiolabial line angle.

2.Distolabial line angle.

3.Mesiolingual line angle.

4.Distolingual line angle.

5.Incisolabial line angle.

6.Incisolingual line angle.

Line angles af posterior teeth:

Eight in number: (IMP)

1.Mesiobuccal line angle.

2.Distobuccal line angle.

3.Mesiolingual line angle.

4.Distolingual line angle.

5.Occlusobuccal line angle.

6.Occlusolingual line angle.

7.Occlusomesial line angle.

8.Occlusodistal line angle.

Point angles Of Teeth

Definition:

Point angle is the point of meeting of three adjacent surfaces in tooth.

point angles of anterior teeth (Four):1.Mesio-labio-incisal point angle.2.Disto-labio-incisal point angle.

3.Mesio-linguo-incisal point angle. 4.Disto-linguo-incisal point angle.

point angles of posterior teeth (Four):1.Mesio-bucco-occlusal point angle.2.Disto-bucco-occlusal point angle.

3.Mesio-linguo-occlusal point angle. 4.Disto-linguo-occlusal point angle.

Dental Formula Definition:

-Dental formula describe the dentition of one side of the mouth (upper and lower).-Dental formula written by letter, number and horizontal lines.

1-The letter designate the type of the teeth.2- Horizontal line for each tooth type.

3-Number to designate the teeth in the same type.a-The number above the line mean upper teeth.b-The number below the line mean lower teeth.

Dental Formula Of Permanent Teeth Dental Formula Of Deciduous Teeth

Numbering System of TeethIdentification System of Teeth

Definition:

It is a system used to identify the tooth category:

1. Type of tooth (permanent or deciduous).

2. Type of tooth (maxillary or mandibular).

3. Type of tooth (right or left).

4. Type of tooth (central or lateral) (1st, 2nd or 3rd).

5. Type of tooth (incisor, canine, premolar, or molar.

1- Palmer Notation SystemDefinition:

Palmer Notation System is a system used to identify the tooth.This system use:

1.Vertical midline.

2. Horizontal line forming the cross shape.

3. Number in permanent teeth begin from central incisor as number 1,

and the number 8 is the third molar.

4. Letter in deciduous Teeth begin from capital letter A for central

incisor , to letter E for second deciduous molar .

1 2 3 4 5 6 7 88 7 6 5 4 3 2 1

1 2 3 4 5 6 7 8

Palmer Notation System For Permanent Teeth

E D C B A A B C D E

Palmer Notation System For Deciduous Teeth

E D C B A A B C D E

Numbering System of Teeth

8 7 6 5 4 3 2 1

6= 6 = Maxillary right first permanent molar

B=

B= Mandibular left lateral deciduous incisor

Examples:

2. Two Digit System (FDI) = International System

Definition:

Two digit System is a system used to identify the tooth by using two numbers. while,

second number is the number of tooth.

This system use:

1.The first number is the number of quadrant.

For permanent teeth: Quadrant number 1 is the upper right quadrant. The number

of quadrants turned in clock wise direction in which the number 2 is the upper left, 3

is the lower left, and 4 is the lower right.

For deciduous teeth: Quadrant number 5 is the upper right quadrant. The number

of quadrants turned in clock wise direction in which the number 6 is the upper left, 7

is the lower left, and 8 is the lower right.

2. The second number is the number of tooth:

For permanent teeth: from central incisor 1-------8

For deciduous teeth: from central incisor 1----5

MaxillaryRight

PermanentQuadrant

MaxillaryLeft

PermanentQuadrant

Mandibular Right

PermanentQuadrant

Mandibular left

PermanentQuadrant

3

21

4

First digit:Maxillary

RightDeciduousQuadrant

MaxillaryLeft

DeciduousQuadrant

Mandibular Right

DeciduousQuadrant

Mandibular left

DeciduousQuadrant

7

65

8

Second Digit For Deciduous Teeth:61 62 63

64 6555 54 53 52 51

85 84 83 82 81

71 72 73 74 75• Examples:

84 : Four eight is the Mandibular right first deciduous molar.

35 : Three five is the Mandibular left second premolar.Note that: Each number must vocalize separately.

Second Digit For Permanent Teeth:(Black Color Number)

18 17 16 15 14 13 12 1148 47 46 45 44 43 42 41

31 32 33 34 35 36 37 38

21 22 23 24 25 26 27 28

3- Universal System

Definition:Palmer Notation System is a system used to identify the tooth .

This system use:1. Number in permanent teeth: Begin from Maxillary Right Third Molar as (1),

turned in clock-wise direction and end at Mandibular Right Third Molar as (32).

2. Letter in deciduous Teeth: Begin from Maxillary Right second Deciduous Molar

as (A), and turned in clock-wise direction which end at the Mandibular Right Second

Deciduous Molar as (T).

3. Write # : Beside the number or letter to differentiate it from the other systems.

F G H I JA B C D E

T S R Q P

O N M L K• Examples:

Q# : Mandibular Right Second Deciduous Incisor.21# : Mandibular Left First Premolar.

Universal System Of Permanent Teeth

1 2 3 4 5 6 7 832 31 30 29 28

27 26 2524 23 22 21 20

19 18 17

9 10 11 12 13 14 15 16

Universal System Of Deciduous Teeth

Anatomical Landmarks Of Crown:

I- Elevated Landmarks

II- Depressed Landmarks

1. Lobe:Lobe is one of the primary centers of calcification and growth formed during development of the crown.Mature form of the lobes are : cusps, mamelon and cingulum.2. Mamelon:Mamelon is any one of three small rounded elevations located on the incisal ridge of newly erupted permanent incisors only.By time due to friction of eating: Attrition occurred to mamelons and become incisal ridge.

Mamelons

I- Elevated Landmarks

3. CingulumDefinition:Large rounded elevation on the cervical third of lingual surface of anterior teeth.Site:Permanent and deciduous incisors.Permanent and deciduous canine.

4. CuspDefinition:Cusp is an elevation of various size and shape.Origin:Cusp denote a mature form of lobe.Site:1.located on the occlusal surface of posterior teeth.2. incisal third of canine.Shape:Cusp is pyramidal structure has four surfaces and four ridgesStructure:Cusp is composed of enamel, dentin and have a pulp horn .

Classification of teeth according to cusp number:

1.One cusp (termed Cuspid tooth): Canine.2.Two cusps (termed Bicuspid tooth): premolars except mandibular second premolar.3.Three cusps: mandibular second premolar and may be maxillary third molar.4.Four cusps: maxillary molars, mandibular permanent second and third molars, and mandibular deciduous first molar.5.Five cusps: mandibular permanent first molar, mandibular deciduous second molar.

Tubercle

•Definition:

Tubercle is a small elevation on the crown surface result from

excessive formation of enamel.

•Sites:

Palatal surface of maxillary first permanent molar and maxillary

second deciduous molar.

•Terminology:

Cusp Of Carabelli

•Difference between tubercle and cusp:

The tubercle is composed of enamel only .

Definition:

Ridge is a linear elevation on the crown.

I. Types of Ridges according to location:

1. Labial ridge:

It is a ridge extend vertically from cervical ridge to cusp tip of canine.

Site: Labial surface of canine.

2. Lingual ridge:

It is a ridge extend vertically from cingulum to cusp tip of canine.

Site: Lingual surface of canine.

3. Cervical ridge:

It is a ridge that form the Cervical third of facial surface of all teeth.

More elevated in deciduous teeth.

Ridges

4. Buccal ridge:

It is a ridge extend vertically from cervical ridge to cusp tip of premolars.

Site: Buccal surface of premolars.

5. Proximal marginal ridges:

( Mesial marginal ridge and distal marginal ridges).

A.In anterior teeth :

The marginal ridge form the mesial and distal margins of the lingual surface.

B. In posterior teeth:

The marginal ridge form the mesial and distal margins of the occlusal surface.

6. Incisal ridge:• It is a ridge found at the incisal margin of anterior teeth.

• by time and attrition it become incisal edge.

7. Cusp ridge:

It is a ridge extend from cusp tip and descend toward mesial or distal surface .

Site: Buccal surface of premolars.

Crown Elevations:1- Cingulum

2- Marginal ridges:

A. Mesial marginal ridges.

B. Distal marginal ridges.

3- Incisal ridge.

4- Cusp ridges:

A. Mesial cusp ridges.

B. Distal cusp ridges.

5- Lingual ridge.

1

2

1

2

3

45

II. Types of Ridges according to shape:

1. Triangular ridge:oIt is a ridge begin from the cusp tip toward the center of occlusal surface.

oIt named triangular ridge because the slope of each side of the ridge are inclined

to resemble a two sides of triangle.

oAlso, it is named occlusal ridge.

2. Transverse ridge:oSite→ Occlusal surface of lower first premolar.

oShape→ This ridge will cross the occlusal surface transversely.

oResult from→ Union of triangular ridges of buccal and lingual cusps.

3. Oblique ridge:oSite→ Occlusal surface of maxillary molars.

oShape→ This ridge will cross the occlusal surface obliquely.

oResult from→ Union of two triangular ridges of mesiolingual cusp and distobuccal

cusp.

Triangular ridge Transverse ridge Oblique ridge

Tubercle of Carabelli.

II- Depressed Landmarks1. Developmental Groove:

Definition:Developmental Groove Linear depressions found on occlusal surface and may

extend labially, buccally, lingually or mesially.

Origin:Line of fusion of primary lobes.

Types:

1. Central developmental groove on the occlusal surface of teeth.

2. Buccal developmental groove: Comes from occlusal to the buccal surface.

3. Lingual developmental groove: Comes from occlusal to lingual surface.

4. Mesial developmental groove: Comes from occlusal to mesial surface of

maxillary first premolar.

5. Labial developmental groove: Comes from incisal to labial surface.

Central Developmental Groove

Lingual developmental Groove

Buccal Developmental Groove

2. Supplemental groove:

Definition: Supplemental groove is a shallow linear

depression on the occlusal surface

branched from the developmental groove.

Origin: They are auxiliary grooves radiating from

developmental groove.

They are do not represent union between

lobes.

Site: Third molar and maxillary second premolars

are the common sites.

Central Developmental Groove

supplemental Grooves (red)

3. Fissure:

Definition: Fissure is a deep linear cleft on the

occlusal or buccal surfaces found in the bottom of the developmental groove.

Origin: Fissure result from incomplete

union of enamel between lobes.Clinical significance: Fissure is the most common site for

development of dental caries.

Complete union of enamel.

Incomplete union of enamel.

4. Sulcus:

Definition: Sulcus is a long tent shaped depression passing between the cusp tips

of the occlusal surface of posterior teeth.

5. Fossa:Fossa is a round or triangular shallow

depression.Types and Site:A. Central fossa: Union between three or four lobes.

On the central part of occlusal surface

of both molars and second mandibular

premolars.

B. Mesial and distal triangular fossa:

On the occlusal surface of posterior teeth

beside marginal ridges.

C. Lingual fossa: On the lingual surface of anterior teeth.

Lingual fossa of canine is divided into

two lingual fossae by lingual ridge.

5. Pits:• Pit is a pin point depression found in the

bottom of fossa.Origin: pits result from incomplete union of

enamel between lobes. Site:A. Occlusal surface of posterior teeth.

B. Lingual surface of anterior teeth

commonly in maxillary permanent lateral

incisor.

C. Buccal and lingual surface at the end of

buccal and lingual developmental groove

( termed faulty pit).

Common caries in the oral cavity:

Pit and fissure caries.