This document discusses the origin and composition of dental pulp and dentin. It provides details on: - The main types of dentin including primary, secondary, and tertiary dentin. - Dentin composition, with inorganic components like hydroxyapatite and organic components like collagen. - Dentin tubule structure from the dentinoenamel junction to the pulp with descriptions of their contents. - Age-related changes in dentin including formation of secondary dentin, sclerotic dentin, and dead tracts.

1. DENTIN I
DR.VIGNESH.R, BDS

2. ORIGIN OF DENTAL PULP
■

3. ORIGIN OF DENTAL PULP
■

4. ORIGIN OF DENTAL PULP
■

5. INTRODUCTION
■ FORMS BULK & GENERAL FORM OF
TOOTH
■ DETERMINES SHAPE OF THE CROWN
( CUSPS, RIDGES & NUMBER AND SIZE
OF ROOTS)
■ CONTAINS CYTOPLASMIC
EXTENSIONS OF ODONTOBLASTS

7. DENTIN ------ BONE
■ PHYSICALLY & CHEMICALLY
RESEMBLES BONE
■ MAIN DIFFERENCE
BONE  ENCLOSED OSTEOCYTES
DENTIN  ONLY THE PROCESS OF
ODONTOBLAST

8. PHYSICAL & CHEMICAL
PROPERTIES
■ Color : light yellowish, becoming darker
with age
■ Viscoelastic & subject to slight deformation
( prevents fracture of overlying enamel )
■ Harder than bone, softer than enamel
■ Harder in its central part than near the pulp
or on its periphery

9. DENTIN OF PRIMARY TEETH  LESS
HARD THAN THAT OF PERMANENT
TEETH
MORE RADIOLUCENT THAN ENAMEL

10. DENTIN - COMPOSITION
■ BY WEIGHT, CONTAINS
70% INORG, 20% ORG, 10% WATER
■ BY VOLUME,
45% INORG, 33% ORG, 22% WATER

11. COMPOSITION
■ INORGANIC :
SUBSTITUTED HYDROXYAPATITE IN THE FORM
OF SMALL PLATES
■ ORGANIC :
90% COLLAGEN ( MAINLY TYPE I, LESSER
AMOUNT OF III & IV )
WITH VARIOUS NON-COLLAGENOUS MATRIX
PROTEINS & LIPIDS

12. NON - COLLAGENOUS
PROTEINS
❖ PACK THE SPACE BETWEEN
COLLAGEN FIBRILS
❖ ACCUMULATE ALONG THE PERIPHERY
OF DENTINAL TUBULES

13. NON COLLAGENOUS
PROTEINS…
1. DENTIN PHOSPHOPROTEIN /
PHOSPHORYN (DPP)
2. DENTIN SIALOPROTEIN (DSP)
3. DENTIN GLYCOPROTEIN (DGP)
4. DENTIN MATRIX PROTEIN-1 (DMP1)
5. OSTEONECTIN
6. OSTEOCALCIN

14. 7. BONE SIALOPROTEIN (BSP)
8. OSTEOPONTIN
9. MATRIX EXTRACELLULAR
PHOSPHOGLYCOPROTEIN
10. PROTEOGLYCANS
11. SOME SERUM PROTEINS

15. TYPES OF DENTIN
1. PRIMARY DENTIN
2. SECONDARY DENTIN
3. TERTIARY DENTIN

18. Primary dentin
■ DENTIN FORMED BEFORE ROOT
COMPLETION
■ FORMS MOST OF THE DENTIN BULK
■ TWO TYPES : A) MANTLE DENTIN
B) CIRCUMPULPAL DENTIN

19. Mantle dentin
■ FIRST FORMED DENTIN
■ JUST ADJACENT TO DEJ
■ SOFT  PROVIDES CUSHIONING EFFECT
TO THE TOOTH
■ WIDTH : FROM 20 μM TO 150 μM
■ CONTAIN LARGER COLLAGEN FIBERS
ARGYROPHILIC  VON KORFF’S FIBRES
( TYPE III COLLAGEN )

20. Circumpulpal dentin
■ REMAINING PART OF PRIMARY DENTIN
■ FORMS MAJOR PART OF TOOTH
■ COLLAGEN FIBERS  SMALLER &
MORE CLOSELY PACKED

21. Primary dentin

22. MANTLE CIRCUMPULPAL
■ LESS MINERALISED
■ COLLAGEN FIBERS
PERPENDICULAR
TO DEJ
■ TUBULES BRANCH
PROFUSELY
■ COLLAGEN FIBERS
LARGER
■ MORE MINERALIZD
■ NOT
PERPENDICULAR
■ LESS / NO
BRANCHING
■ SMALLER COLLAGEN

23. Secondary dentin
■ REPRESENTS DENTIN FORMED AFTER
ROOT FORMATION
■ MUCH SLOWER DEPOSITION
■ ALL THROUGH THE LIFE
■ CONTAINS FEWER TUBULES
■ CONTINUOUS WITH THAT OF PRIMARY
DENTIN
■ LESS REGULAR

24. Sec dentin..
■ NOT DEPOSITED EVENLY AROUND
PULP CHAMBER
■ GREATER DEPOSITION ON ROOF &
FLOOR OF CHAMBER  REDUCTION
IN SIZE & SHAPE
■ AS AGE INCREASES, SIZE OF PULP
CHAMBER DECREASES

25. Sec dentin..
■ TUBULES SCLEROSE MORE READILY
THAN THOSE OF PRIMARY DENTIN
■ RESULTS IN REDUCED PERMEABILITY
OF DENTIN  PROTECT PULP

26. Secondary
dentin

27. Tertiary dentin
■ PRODUCED IN REACTION TO VARIOUS
STIMULI  ATTRITION, CARIES OR
RESTORATIVE DENTAL MATERIALS
■ LOCALISED  PRODUCED ONLY BY
CELLS DIRECTLY AFFECTED BY THE
STIMULUS / INJURY

28. TERTIARY DENTIN…
■ TUBULES IN TERTIARY DENTIN
SPARSE IN NUMBER & IRREGULARLY ARRANGED
OR
NO TUBULES
■ ODONTOBLAST CELLS MAY LINE THE SURFACE OF
NEWLY FORMED DENTIN
OR BECOME INCLUDED INSIDE IT = RESEMBLE
BONE & OSTEOCYTES (OSTEODENTIN )

29. 2 TYPES OF TERTIARY DENTIN
1. REACTIONARY DENTIN : DEPOSITED BY PRE-
EXISTING ODONTOBLASTS WHICH ARE STILL
VITAL (EVEN AFTER INJURY)
2. REPARATIVE DENTIN : BY NEWLY
DIFFERENTIATED ODONTOBLAST-LIKE CELLS
(WHEN ODONTOBLASTS GET INJURED AND NON-
VITAL)

30. DENTINAL TUBULE
■ SMALLEST STRUCTURAL
UNIT OF DENTIN

31. ‘S’ SHAPED FROM DEJ TO
PULP
SIGMOID SHAPE > IN CROWN
ROOT DENTIN  MORE
STRAIGHT

34. THE BASIC “S” / SIGMOID
CURVATURE OF TUBULES
PRIMARY CURVATURE

35. MOST EVIDENT AT JUNCTION OF
PRIMARY & SECONDARY DENTIN
PRIMARY CURVATURE

36. SMALLER CHANGES IN
TUBULE DIRECTION
(CURVATURE)
SECONDARY CURVATURE

37. AVERAGE DIAMETER OF A
TUBULE = 1 – 4 μM
1 – 2 μM AT DEJ
3 – 4 μM AT PULP BORDER

38. 70,000 – 90,000 TUBULES
AT DEJ
20,000 – 60,000 NEAR PULP

39. TUBULES CONTAIN
ODONTOBLAST PROCESSES
END AT DEJ
SOMETIMES EXTEND INTO
ENAMEL AS SPINDLES

40. CONTENTS OF D. TUBULES
ODONTOBLAST PROCESSES
NERVE TERMINALS (ENDINGS)
PROCESSES OF ANTIGEN PRESENTING
CELLS OF PULP
DENTINAL FLUID

42. SMALL SIDE-BRANCHES OF
DENTINAL TUBULES
LATERAL BRANCHING
IMPORTANT PATHWAYS FOR CARIES
SPREAD

46. FIRST LAYER OF DENTIN TO
BE FORMED BY
ODONTOBLASTS
?????

47. FIRST FULLY MINERALIZED
LAYER OF DENTIN TO BE
FORMED
????

48. THAT LAYER OF DENTIN
CLOSE TO DEJ
????

49. THAT LAYER OF DENTIN FORMING A
“COVER” OVER THE WHOLE DENTIN
?????

50. THICKER, MORE MINERALIZED
LAYER OF DENTIN

51. THAT LAYER OF DENTIN FORMED
AFTER ROOT FORMATION
????

52. SMALL VESICLES (GLOBULES) OF
MINERALS FORMED ON COLLAGEN
MATRIX
MINERALIZATION OF DENTIN

53. THESE MINERAL GLOBULES
GRADUALLY FUSE
TO FORM A CONTINUOUS LAYER
OF MINERALIZED DENTIN

54. IN SOME AREAS,
GLOBULES FAIL TO FUSE
DENTIN BETWEEN THESE
GLOBULES  LESS MINERALIZED

55. INTERGLOBULAR DENTIN
HYPOMINERALIZED AREAS IN
DENTIN DUE TO LACK OF FUSION
OF MINERAL GLOBULES

56. USUALLY BENEATH
MANTLE DENTIN
■ AT THE JUNCTION BETWEEN
MANTLE & CIRCUMPULPAL
DENTIN

57. LACK OF MINERALS IN
THIS AREA
LEADS TO INTERNAL REFLECTION
OF LIGHT  MICROSCOPY

58. INTERGLOBULAR DENTIN IN
GROUND SECTIONS
APPEARS DARK IN
TRANSMITTED LIGHT

61. LINES OF CURVATURES /
INCREMENTAL LINES
STRUCTURAL LINES IN DENTIN

62. 1.SCHREGER LINES
COINCIDE WITH PRIMARY
CURVATURE

63. 1. SCHREGER LINES
SEEN AS BROAD CONCENTRIC
BANDS IN C.S
AS ONE BROAD BAND IN L.S.

65. 2. CONTOUR LINES OF OWEN
DUE TO THE SMALLER
SECONDARY CURVATURES

66. 2. CONTOUR LINES OF OWEN
■ NOT ALWAYS SEEN
■ SEEN AS A LINE CROSSING THE
STRUCTURE OF DENTIN AT LOW
MAGNIFICATION
■ MOST EVIDENT AT PRIMARY – SECONDARY
DENTIN JUNCTION

68. 3. ANDRESEN LINES
SAME AS STRIAE OF RETZIUS
IN ENAMEL

69. 3. ANDRESEN LINES
LONG PERIOD INCREMENTAL LINES IN
DENTIN
MAY BE SEEN AS DARK & LIGHT BANDS
AT RIGHT ANGLES TO DENTINAL TUBULES

70. 4. VON EBNER’S LINES
SAME AS ‘CROSS STRIATIONS’
IN ENAMEL

71. 4. VON-EBNER’S LINES
■ SHORT PERIOD INCREMENTAL LINES
■ DARK AND LIGHT BANDS
■ DIURNAL PATTERN OF DENTIN
DEPOSITION

73. 5. NEO – NATAL LINE
SEPARATES PRENATAL AND
POST NATAL DENTIN

74. DENTIN IMMEDIATELY
SURROUNDING THE ODONTOBLAST
PROCESSES
PERITUBULAR DENTIN

75. HIGHLY MINERALIZED
LESS COLLAGEN (ORGANIC)

76. PERITUBULAR DENTIN
■ ALSO CALLED “INTRA-TUBULAR DENTIN”
■ CONTAINS LESS ORGANIC MATRIX
(COLLAGEN)
■ “HYPERMINERALIZED” AREA IN DENTIN
■ APPEARS DENSE ON X-RAYS

78. THE DENTIN IN BETWEEN
DENTINAL TUBULES
INTER-TUBULAR DENTIN

79. LESS MINERALIZED THAN
PERI-TUBULAR D
CONTAINS MORE OF
COLLAGEN MATRIX

81. DENTINAL TUBULES GET
OCCLUDED BY MINERALS
SCLEROTIC DENTIN

82. SCLEROTIC DENTIN
■ AGE –RELATED CHANGE IN DENTIN
■ TUBULES OCCLUDED
■ TO PREVENT FURTHER SPREAD OF INFECTION /
STIMULUS
■ TUBULAR STRUCTURE LOST
■ APPEARS TRANSPARENT

83. TUBULES GET OCCLUDED
WITH PERI-TUBULAR DENTIN
TRANSLUCENT DENTIN

84. TRANSLUCENT DENTIN
■ AGE – RELATED CHANGE IN DENTIN
■ MORE IN ROOT DENTIN
■ TO PREVENT INJURY TO PULP
■ BY BLOCKING TUBULES
■ STARTS AT APEX
■ PROGRESSES UP WITH AGE

85. ODONTOBLAST PROCESSES
WITHIN TUBULES DESTROYED
DUE TO INJURY / INFECTION

86. TUBULES APPEAR EMPTY
GET SEALED BY TERTIARY
DENTIN AT ENDS

87. IN GROUND SECTIONS
■ MOUNTING MEDIUM WILL NOT ENTER
SUCH TUBULES (SEALED BY TERTIARY
DENTIN AT THE END)
■ THEY REMAIN FILLED WITH AIR

88. IN GROUND SECTIONS
■ DARK  TRANSMITTED LIGHT
■ WHITE  REFLECTED LIGHT

89. THIS APPEARANCE OF EMPTY
TUBULES SEALED BY
TERTIARY DENTIN
“DEAD TRACTS”

92. AGE-CHANGES IN DENTIN
■ SCLEROTIC DENTIN
■ TRANSLUCENT DENTIN
■ DEAD TRACTS
■ SECONDARY DENTIN

93. THEORIES OF DENTIN
SENSITIVITY
■ DIRECT INNERVATION THEORY
■ TRANSDUCTION THEORY
■ FLUID HYDRODYNAMIC THEORY