Pulp and Dentin

Pulp and Dentin are formed from what?

Dental papilla-helped by neural crest cells

__________Is non-calcified, loose connective tissue and very vascular.

Pulp

_______Is calcified, highly specialized, avascular connective tissue.

Dentin

Three components of Pulp?

Cells
Fibers
Ground Substance

Coronal pulp

Contains more cells, fibers, blood vessels and nerves than the radicular pulp

Radicular pulp

Connecting tube, carries blood to and from the coronal pulp through the apical canal

Areas of the Pulp

Central Zone
Peripheral Zone

Peripheral zone is also known as?

Odontogenic zone

Characteristics of the central zone?

Contains large arteries, veins and nerve trunk. Fibroblasts predominate along with ground substance and collagen fibers

List the 4 areas of the odontogenic zone

OCCP

O-dontoblasts *Orange
C-ell-free zone *Cars
C-ell-rich zone *Collect/Rich
P-arietal plexus *People

Cell types found in the pulp?

FOSMWRM

Fibroblasts
Odontoblasts
Schwann Cells
Macrophages
WBC
RBC
Mast Cells

Which cell type is most numerous in the pulp?

Fibroblasts

Characteristics of the odontoblast in Pulp.

FPLD
Found at the Periphery
Produces dentin
Larger at the coronal than radicular pulp
Develops an odontoblastic process that extends from the pulp to the enamel

What are the nerve fibers found in pulp?

Autonomic sympathetic
Afferent

Funtion of Autonomic Sympathetic nerve fibers

Regulate the flow of blood in vessels

Function of the Afferent nerve fibers

Sensory function, perception of pain

Age/trauma related changes in the pulp?

-pulp decreases due to continued deposition of dentin
-Increase in collegen fibers
-Denticles (pulp stones)

Characteristics of pulp stones/dentricles

-people over 50
-oval calcified masses in the pulp
-may or maynot be result of stress

Two types of pulp stones/dentricles?

-True
-False

Which denticle has tubules?

True

Which denticle does not have tubules?

False

Three types pulp stones

-Embedded
-Attached
-Free Floating

Dentin is produced by __________growth.

Appositional

How is Dentin classified?

According to when it was made.

Characteristics of Dentin.

*Living tissue composed of collagen fibers and hydroxyapatite
*Continues to grow throughout life
*Odontoblast cells that produce dentin
*Less mineralized than enamel
*more yellow than enamel

Dentin is what % mineralized?

70%

Enamel is what % mineralized?

96%

What stage of tooth develpment does dentin begin to form?

Late Bell Stage

Dentinogenesis

Is the formation of Dentin

Odontoblasts develop an extension called _______________

Odontoblastic process

The odontoblast process is protected by the ___________

Dentinal tubule that extends from the odontoblast to the DEJ

Types of Dentin

*Primary
*Secondary
*Tertiary

Characteristics of tertiary dentin?

Aka Reparative dentin
Result of pulpal irritation
Forms rapidly
Trauma (caries, attrition, restorations)

Characteristics of Primary Dentin?

Major component of crown and root.
consists of Mantel dentin and Circumpupal dentin
*Deposited b4 completion of apical foramen

Characteristics of secondary dentin?

Forms after tooth is complete formed
Responsible for pulp decreasing in age
Forms slower & more calcified than primary.

Formation of Primary dentin (4 types of dentin)

MICT

Mantel dentin
Interglobular dentin
Circumpulpal dentin
Tomes granular layer of dentin

Mantel dentin

Oldest
Closest to DEJ
First layer of dentin
Free of developmental defects
*Caries that reach the dentin will spread quickly along the mantel layer

Interglobular dentin

small areas of UNMINERALIZED
DEFECTIVE dentin @ the base of mantel dentin
*result of vitamin D deficiency
*Coronal portion of tooth

Tomes granular layer of dentin

Unmineralized
Below the cementum (root portion)
could be result of looping and twisting of dentinal tubules in this area

Circumpulpal dentin

Lies beneath the mantel layer of dentin
*Makes up the bulk of the primary dentin
*thinner at the root section
*Maybe 6-8 mm thick in crown
*Collagen fiber are 10X smaller than those in the mantel dentin

During dentin formation what 2 things happen?

*organic matrix is deposited
*mineralization occurs

Dentin formation

IPPD
*Predentin
*Dentinal Tubule
*Peritubular dentin
*Intertubular dentin

Predentin

*nearest the pulp
*newly band of unmineralized matrix of dentin formed by the odontoblasts at the pupal border

Dentinal Tubule

The odontoblast needs to be proteccted. It is contaied with in a dentinal tubule along with a nerve fiber.

Peritubular dentin

aka dentinal tubule
*hypermineralized collar of dentin that surrounds the dentinal tubule, which house the odontoblast process.

Intertubular dentin

THE MAIN BODY OF DENTIN

Dentinal tubules run from _____to the ______

DEJ, Periphery of the pulp where odontoblast reside.

Oldest dentin is near the?

DEJ

Youngest dentin is near the?

Pulp

Dentinal tubules are ____shaped? What kinds?

S
Primary & Secondary

Primary S Shape

Caused as the odontoblasts move toward the pulp, and therefore form a wider area to a narrower area
*A result of Crowding, less prominent in the root

Secondary S Shape

Waves seen along the length of the tubule. May reflect daily changes of the odontoblast.

Secondary tubules (canaliculi)

perpendicular brances of primary tubule. More branching @ ends near crown.

The highest density of tubules is @______ and it results in _____.

@ DEJ
Sensitivity

The 2nd most sensitive area of the tooth is?

@ DEJ

The most sensitive area of the tooth is where?

Pulp

Dead tract

Dentinal tubule that remains unfilled after the odontoblast process has degenerated. May progress to sclerotic dentin.

Sclerotic dentin

*Dentin tubules completely obliterated by calcium salt. *Protective mechanism for the pulp
*Increases with age
*Found in areas of attrition, abrasion, caries or fracture

Dead tracts are _________and sclerotic dentin is________.

Black White

Evidence of incremental formation of dentin is seen as:

1 Von ebners line
2 neonatal line
3 contour line of owen

Von ebners line

caused by periods of inactivity or growth of dentin. Hypocalcified area
Daily production

Neonatal line

the division between dentin formed b4 birth and after

Contour line of OWen

can be correlated with a pause in activity due to tramatic event. High fever, illness, stroke

Hydrodynamic theory of pain.

Related to tissue fluid pressure-When dentin is stimulated fluid and the odontoblast process move within the tubule. Nerve fibers detect the change and produce an impulse to brain (pain).