Tooth Dentin

2. Introduction
• Dentin is the mineralized hard tissue
forming the main bulk of the tooth.
• Covered by
- Enamel in Crown
- Cementum in Root

3. Physical Properties
• It is light yellowish in color, becoming darker with age.
• Viscoelastic Material (Harder than bone but softer than
enamel)
• Lower content of mineral salts in dentin renders it more
radiolucent than enamel

4. Chemical Properties
70 %
30%
Organic Matter + Water
substance consists of
collagenous fibrils and a
ground substance of
mucopolysaccharides
(proteoglycans and glycos
aminoglycans
Inorganic Matter
consists of
hydroxyapetite as
in bone, cementum &
enamel

6. Dentinal Tubules
• Extend from DEJ to Pulp (entire Dentin thickness)
• starting at right angle to pulp
• End perpendicular to DEJ and DCJ

7. Curvatures Of Dentinal Tubules
1- Primary Curvature
2- Secondary Curvature

8. Dentinal Tubules
Primary Curvatures
• ‘S’ shaped curve.
(Sigmoid curvatures)
• More prominent in crown
• Straight at
- cusp tips
- incisal edge

9. Dentinal Tubules

10. Dentinal Tubules
Root Dentin
Coronal Dentin

11. Dentinal Tubules
Secondary Curvature
Spiral in Shape

12. Content Of Dentinal Tubules
Dental lymph

13. Content Of Dentinal Tubules

14. A, Dentinal tubule; B, DEJ;
C, Enamel; D, Enamel spindle

15. Each cell gives rise to one process, which
traverses the predentin & calcified dentin
within one tubule

16. Dentin Pulp

18. Types Of Dentin
• According to :
1- Defect uniform in structure
2- Ultra Structure
3- Age Change

19. According to defect uniform in structure
Tome s Granular layer
Interglobular Dentin
Root
Crown
Looping of Dentinal Tubules
hypomineralized islands within the
Dentin formed due to failure of fusion
of mineral globules
Small
Large
Ground Sec only
Ground Sec. & Decalcified sec

20. Interglobular Dentin

21. Tome s Granular layer

22. According to UltraStructure
Intertubular Dentin
Peritubular Dentin
Between D.T
Wall Of D.T
Less in Hardness
High in Hardness
Form main bulk of dentin

25. T.S. In Dentinal Tubules

26. INCREMENTAL LINES
- Von Ebner Line
- Contour Line of Owen
- Neonatal Line

27. Von Ebner Line
- Fine striations - perpendicular to tubules
- Shows the daily deposition of Dentin

28. Contour Line of Owen
- Due to the “Co-incidence of secondary curvatures”
- Accentuated Von ebnar incremental line
- Shows Hypo-mineralized areas

31. Neonatal Line
-Accentuated Incremental line
- Prenatal and postnatal dentin separated by
neonatal line
- Primary teeth, permanent first molars
- Reflects abrupt change in environment that
occurs at Birth.

32. Neonatal Line

33. According to Age Change
Primary dentin Secondary physiologic
dentin
Tertiary dentin or
reparative dentin or
reactionary dentin or
irregular secondary
Mantle Dentin Circumpulpal dentin

34. Primary Dentin
Circumpulpal
dentin
Mantle Dentin
After Root Completion
Before Root
Completion
Form Remaining Primary
Dentin
(Bulk Of Tooth )
First Formed Dentin layer
Most Peripheral part of
primary Dentin
Contain more mineral
Contain Less Mineral

35. Secondary Dentin
 forms after root formation is
complete
 narrow band of dentin
bordering the pulp
 Contains fewer tubules
than primary dentin
 Less regularty than primary
dentin

38. Tertiary dentin
 Reactive Dentin, Reparative Dentin, Irritation Dentin, Replacement Dentin, Defense
Dentin
 Localized formation of Dentin At pulp –Dentin Border in response to noxious
stimuli ( Caries, Trauma, Attrition , Cavity Preparation )
 No continuity with primary or secondary Dentin so there is decrease in Dentin
permeability
 Tubules may or may not be present

41. Sclerotic Dentin
 Dentinal tubules become
occluded with calcified
material
 Blocking of tubules- Defensive
reaction.
 Elderly people – Mostly in Roots
 Found specially in radicular
dentin (apical 3rd).
 Transparent or light in
transmitted Light
 dark in reflected light
 Cause : Mild Stimuli

42. Sclerotic Dentin

43. Dead tracts
 Complete Destruction of Odontoblastic process in the affected area
 Dark in transmitted Light
 Transparent or light in reflected light
 Cause : Sever stimuli
A, Dead tract;
B, teritary dentin

44. Test YourSelf ??

45. A
B
C

46. A
B
C
D

50. A

63. Thank You