1. Dentin Pauline Hayes Garrett, D.D.S.
Department of Endodontics, Prosthodontics, and Operative Dentistry
University of Maryland, Baltimore

2. This material was taken from:
Essentials of Oral Histology and Embryology, third edition, Leslie P Gartner, 1999, Jen House Publishing Co. Chapter 3
Ten Cate’s Oral Histology Development, Structure, and Function, Antonio Nanci, sixth edition, 2003, Mosby, Chapter 8

3. Objectives: To recognize and apply the following concepts to clinical dentistry:
Physical Properties of Dentin
Dentinal Tubules
Peritubular Dentin
Intertubular Dentinal
Types of Dentin
Peritubular
Intertubular
Primary Dentin
Secondary Dentin
Tertiary Dentin
Dead Tracks
Sclerotic Dentin
Globular Dentin
Interglobular Dentin
Markings on Dental Tubules
Daily imbrication lines of von Ebner
Contour Lines of Owen
Neonatal line
Dentin Intervention
Granular layer of Tomes
Hyline layer of Hopewell-Smith
Root Dentin
Nerve Fiber Theory
Odontoblastic process Theory
Hydrodynamic Theory

4. Physical Properties of Dentin
Dentin :located in crown and root.
65-70% mineralized substances
20-25% organic material
10% bound water.
The mineralized :calcium hydroxyapatite.
The organic material :collagen and ground substance.
Color: yellow.
Highly elastic: support substance for Enamel
Dentin is living tissue.
The odontoblasts reside in the pulp and continue to be active throughout the life of the tooth.
Illustration reprinted and modified from: Oral Histology and Embryology, second edition, Gartner, 1999 pg. 46. with permission from Dr. Leslie P. Gartner

5. Dentinal Tubules Enclosed spaces Surrounded by peritubular dentin
A scanning electron microscope specimen of
dentinal tubules. Reproduced with permission
from Mathias Nordve, IOB,UiO, University of Oslo.

6. Dentinal Tubules Primary Curvature is: S-shaped
Secondary Curvature: jagged or wrinkled texture
Curvatures result from movement of odontoblasts during development

7. Coronal portion= “S”shaped curvature.
Vs.
Root portion= more Straight path.

8. Dentinal Tubules
“S” shape primary curvatures of coronal dentin on the right.
Photomicrograph of decalcified dentin and illustration below, show the second degree curves in dentin
Histological slides prepared and provided by the Department of Biomedical Sciences, University of Maryland, Dental School.

9. Dentinal Tubules, Peritubular dentin and Intertubular dentin
Dentinal tubules contain = extracellular fluid (ECF)
- From pulp and provides nutrients
- From the pulp to the DCJ or DEJ
- Important for pain sensation

10. Dentinal Tubules, Peritubular dentin and Intertubular dentin
A scanning electron microscope specimen of dentinal tubules. Reproduced
with permission from Mathias Nordve, IOB,UiO, University of Oslo.

11. Types of Dentin - Primary Dentin: - Secondary Dentin:
all dentin formed prior to root formation or completion.
- Secondary Dentin:
all dentin produced after root formation or completion. (NOT due to trauma)
- Tertiary Dentin:
all reparative dentin (all regular and irregular)*

12. Types of Dentin: Primary Dentin
Two Types: All collagen in Dentin is produced by Odontoblasts.
Mantle Dentin (M) is the first formed dentin. It is located in both the crown underlying the DEJ and the root of the tooth.
~20 micrometers thick.
Fibers are perpendicular to the DEJ.
Contains von Korff’s fibers
Circumpulpal dentin: the remaining and the bulk of primary dentin.
The collagen fibers are much narrower (~0.05 micrometers thick) than mantle dentin..
It is more mineralized than mantle dentin.
It is more compactly arranged collagen fibers than mantle dentin..
Mantle Dentin (M arrow)
Ameloblasts (A), Odontoblasts (O).
Histological slide prepared and provided by the Department of Biomedical Sciences, University of Maryland, Dental School.

13. Types of Dentin: Secondary Dentin
around the pulp chamber
subsequent to root completion.
not a response to trauma.
formed at a slower rate than primary dentin.
fewer tubules than primary dentin.
formed in an unequal fashion
more on the roof and floor of the pulp than on the walls.
usually has a bend in the direction of the tubules where primary and secondary meet.
Image reprinted from the Leeds University: The Virtual Oral Histology Laboratory

14. Types of Dentin: Tertiary Dentin
Reparative Dentin:
2 kinds:
regular
irregular
Histological slide prepared and provided by the Department of Biomedical Sciences, University of Maryland, Dental School.

15. Types of Dentin: Dead Tracks
Dead Tracts are empty dentinal tubules that lead directly to pulp
Due primarily to caries

16. Types of Dentin: Sclerotic
Sclerosis
minerals within tubules.
highly mineralized
Deposited inside tubules.
The tubules smaller in diameter
less permeable
transmit stimuli to a lesser degree.
Image reprinted from the Leeds University: The Virtual Oral Histology Laboratory

17. Types of Dentin: Globular vs. Interglobular Dentin
Arrows = interglobular dentin.
Histological slide prepared and provided by the Department of Biomedical Sciences, University of Maryland, Dental School.

18. Markings on Dentin Tubules:
Segments = Contour Lines of Owen
Lengthwise section of a Dentin tubule
Striations = Daily Imbrication Lines of Von Ebner

19. Dentin: Granular layer of Tomes/ Hyaline layer of Hopewell-Smith
In peripheral most layer of radicular dentin.
Hyaline of Hopewell- Smith
Clear layer between the granular layer of Tomes and cementum Facilitates the adherence of cementum and dentin.
Histological slides prepared and provided
by the Department of Biomedical Sciences,
University of Maryland, Dental School.

20. Root Dentin Lines of Owen. (O arrows)
The radiating lines represent dentinal tubules (T arrows)
The light semicircular line is called the hyaline layer of Hopewell-Smith (H)
The thin dark line is the dentinocemental juntion.
The cementum (C)
Periodontal ligament (P) is cementoid (uncalcified cementum).
Cross section of a decalcified root

21. Clinical Significance: Natural Desensitization
Sclerosis of dentin
Secondary
Tertiary dentin.

22. Clinical Significance: Tetracycline staining and Bleaching

23. THE END