The Crown and the Root

Anatomical crown

portion covered by the enamel surface

clinical crown

portion of tooth which is visible or exposed to outside in the mouth

anatomical root

portion covered by cementum

clinical root

portion of tooth which is not visible in the mouth

cervical line

a thin line which separates the anatomical crown and the anatomical root.
it is also termed as Cemento-enamel junction (CEJ)

root trunk

it is the part of the root which starts from the cervical line to the furcation area of multirooted teeth (posterior only)

furcation

It is the junction of roots in multirooted teeth mainly in posterior.

Apex

It is the tapered end of the root tip of a tooth.

Apical Foramen

It is a communication channel or opening between the periodontal membrane and the pulp. It is usually

present at the apex of the root. Its plural form is foramina.

apical foramina

plural form of apical foramen

enamel (substantia adamantina)
dentin (Substantia eburnea)
cementum (Substantia ossea)

what are the types of hard dental tissues

Enamel

A hard, mineralized tissue which covers the dentin of the

anatomical crown of a tooth and hardest living body tissue.

5-8 Moh

what is the hardness of enamel?

yellow white

what is the color of enamel if its thin?

bluish or grayish

what is the color of enamel if its thick?

outer covering of the crown

location of enamel

96%

inorganic content of enamel?

4% organic matter and water by weight.

Organic content and water of enamel

they are less mineralized

why is the enamel of deciduous teeth has slightly higher organic content than permanent teeth?

nonliving

Is enamel living or non-living

semi-translucent (soluble is acid media)

what is the transparency of enamel?

Selectively permeable

What is the permeability of enamel?

inter prismatic substance

What is found between the enamel rods/prisms?

2.8

specific gravity of enamel?

dentin

Hard tissue which forms the main body of a tooth and surrounds the pulp cavity and is covered by enamel in the anatomical crown and by cementum in the anatomical root.

Enamel

What covers dentin in the anatomical crown?

Cementum

What covers dentin in the anatomical root?

basic shape

What does dentin provide to the tooth?

65%

How much inorganic matter does dentin contain by weight?

35%

How much organic matter and water does dentin contain by weight?

dentin has more organic substance than enamel

How does the organic content of dentin compare with enamel?

Protein

What does the organic matter of dentin consist mainly of?

peritubular dentin

Dentin that immediately surrounds the dentinal tubules.

living

is dentin living or nonliving?

Less hard than enamel but harder than bone and cementum.

How hard is dentin compared with enamel, bone, and cementum?

semi-transparent

What is the appearance of dentin?

light yellow

What is the color of dentin in deciduous teeth?

yellow

What is the color of dentin in permanent teeth?

high permeable because of dentinal tubules

What is the permeability of dentin?

dentinal tubules

has cell inside odontoblastic processes/cells

odontoblastic processes

provides sensation in tooth

Dentin has high elasticity and is less radio-opaque than enamel because it is less mineralized

How does dentin compare with enamel in elasticity

cementum

Layer of hard, bonelike tissue which covers the dentin of the anatomical root of a tooth.

cementoenamel junction (CEJ) to the apical foramen

Extent/location of cementum

45–50%, mainly hydroxyapatite

Inorganic component of cementum

50–55%, mainly Type I collagen fibers, proteins, and polysaccharides.

Organic component of cementum

Cellular cementum and acellular cementum

Two types of cementum

Cellular cementum

Commonly found in the apical 1/3 of the root; contributes to root lengthening; also called secondary cementum

Cementocytes

Cells found in cellular cementum

acellular cementum

Generally found in the coronal 2/3 of the root; also called primary cementum

Similar to bone; less hard and less calcified than dentin

How does the hardness of cementum compare with bone and dentin?

Purple, representing the periodontal alveolar fibers

What is the color associated with cementum?

Very permeable.

What is the permeability of cementum?

pulp

soft dental tissues?

Pulp

Living soft connective tissue occupying the pulp cavity of a vital tooth; contains blood vessels, nerves, and lymphatics

Central portion of the tooth

Location of pulp

formative
sensory/protective
nutritive
defensive or reparative

functions of pulp?

coronal pulp

can be found in the pulp chamber of the crown.

Pulp horn (cornu)

extensions of the pulp chamber.

radicular pulp

can be found in the root.

pulp cavity

The entire internal cavity of a tooth which contains

the pulp and consists of a pulp canal, pulp chamber,

and pulp horns.

pulp canal
pulp chamber
pulp horns

The entire internal cavity of a tooth which contains

the pulp and consists of a ?

cemento-enamel junction
dentino-enamel junction
cemento-dentinal junction

junctions of tooth tissues

CEJ

- A thin line which separates the

anatomical crown and the anatomical root.

Dentino-Enamel Junction

Internal line of meeting of

dentin and enamel in the anatomical crown of a tooth.

Cemento-Dentinal Junction

A structural and biological

link between cementum and dentin present in the roots of

teeth.

Alveolar Process

Entire bony entity which surrounds and

supports all teeth in each jaw member.

Alveolus

Bony socket, or portion of alveolar process, into

which an individual tooth is set.

Periodontal Ligament

Fibrous attachment of tooth

cementum to the alveolar bone.

Gingiva

“Gum” or the fibrous tissue enclosed by mucous

membrane that covers the alveolar process and surrounds the

necks of the teeth