February 14, 2008QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

Amelogenesis - The Formation of Enamel

A. Hard Tissue Formation

B. Amelogenesis

C. Structure of Enamel

D. Clinical Correlations

E. Enamel versus Dentin

ENAMEL vs DENTIN

Enamel Spindles

ENAMEL vs DENTIN

Striae of Retzius

ENAMEL vs DENTIN

Perikymata

Enamel: Primary versus Permanent Teeth

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

*Similar enamel structure [except at tooth surface where primary teeth more likely to have a “prismless” surface (lacks enamel rods)]

*Enamel is about twice as thick in permanent teeth

*Postnatal enamel more highly pigmented, so…. enamel of primary teeth whiter than permanent teeth(believed due to primary tooth enamel formed prenatally, not subject to some environmental factors)

http://dentistry.about.com/od/childrensdentistry

Enamel Rod Basics

Enamel rod: *represents “mineralized trail”

taken by ameloblast

*diameter of corresponds to the diameter of columnar ameloblast that formed it

* rods vary in length…short near cervix, in pits & in fissures

* inclination of rods varies more inclined near cusps,

almost vertical near cervix

DENT 5315 & DH 2215 Dentin-Pulp Complex 1

February 14, 2008

A. Dentinogenesis

B. Root Formation

C. Dentin-Pulp Complex

D. Dentin Classification

E. Clinical Correlations

Hard Tissue Formation Bell Stage

Dentinogenesis - Secretory Stage

Dentinogenesis

acellular zone separates ameloblasts from dental papilla

Dentinogenesis

First sign of dentin formation.

Dentinogenesis

arrows show von Korff’s fibers

Pulp

Odontoblasts

Dentin Tubules

Dentinogenesis

Odontoblasts have a cell process.

Dentinogenesis

Note: trapped odontoblast processes at dentino-enamel junction (DEJ)

Odontoblasts have a cell process.

Dentinogenesis

DEJ - Trapped Odontoblastic processes

Dentinogenesis

Odontoblastic cell processes in dentin tubules

Dentinogenesis

Note: collagen fibers & odontoblastic processes in tubules

Dentinogenesis

Note: mineralization foci forming mantle dentin

Odontoblasts produce organic matrix & crystals.

Dentinogenesis

Note: predentin layer

Root Formation

Proliferation of cells from “cervical loop”

Cervical Loop

Root Formation

Formation of Hertwig’s epithelial root sheath.

48

Hertwig’s Epithelial Root Sheath

Root Formation

Sheath grows around dental papilla/future pulp.

THE DENTIN-PULP COMPLEX

Root Formation & Periodontium

Root Formation

56

Formation and narrowing of apical foramen.

The Completed Root

PDL

123

Pulp

Incremental layering of cementum.

Alveolar bone

Apicoectomy

THE DENTIN-PULP COMPLEX

http://www.uic.edu/depts/endo/apico.html

Green Arrows: “Rests of Malassez”

(remnants of Hertwig’s epithelial root sheath)

135

Periodontal Ligament Space