The document provides an in-depth analysis of dentinal tubules, detailing their structure, including the arrangement of dentin types and the role of odontoblasts in dentin formation. It discusses the properties of peritubular and intertubular dentin, various types of dentin, and the clinical significance of dentin hypermineralization and innervation. Additionally, it explores theories of pain transmission related to fluid movement within the dentinal tubules.

2. Dr. Dipen Majumder

3. DENTINAL TUBULE
CONTENT
Odontoblastic process-
cytoplasmic extensions in
dentinal fluid.
COURSE
Primary curvature-
Starting at right angel from the
pulpal surface, doubly convex.
Secondary Curvature-
gradually becomes straighter
toward apical and cuspal region,
sinusoidal in shape.

4. ARRANGEMEN
T
Tubules wider and
closer near pulp.
Tubules farther apart
and narrower near
DEJ or CEJ.
BRANCHE
S
Lateral branches all along
its course.
Terminal branches near
DEJ, more in root dentin.

5. (A)-1 μm in diameter at the DEJ.
(B)-1.5–2 μm midway through dentin.
(C)-1.5–3 μm at the pulp.
(D)-Bacterial penetration follows line of
least resistance to reach the pulp.

6. PERITUBULAR
DENTIN
INTERTUBULAR
DENTIN
o Dentin surrounds
the dentinal
tubule.
o Dentin present
between dentinal
tubules.
o Lacks of collagen
fibrils.
o Type 1 collagen
present.
PERITUBULAR AND INTERTUBULAR
DENTIN

7. PERITUBULAR
DENTIN
INTERTUBULAR
DENTIN
o Deposite inner
wall of the
tubules termed
as ‘intratubular
dentin’
o The main body of
dentin is
composed of
intertubular
dentin.
o Inner organic
lining termed as
lamina limitans.
PERITUBULAR AND INTERTUBULAR
DENTIN

8. PREDENTIN
The predentin always
adjacent to the pulp tissue
and is 2–6 µm wide.
It is not mineralized
Mature dentin-70%
inorganic and 20% organic
material,10% water.

9.  Odontoblasts forming layer
at the periphery of pulp and
processes extending into
the dentin.
 Palisade pattern.
 Junctions between
odontoblasts- Gap junction,
Tight junction,
Desmosomal junction.

10. The life span of the
odontoblasts is equal to the
age of the tooth as once
differentiated, they cannot
undergo further division.

11. DENTIN
(formed before root
complition)
MANTLE DENTIN(formed along DEJ- seen in
crown only)
CIRCUMPULPAL DENTIN(all other dentin formed
before tooth eruption)
DENTIN
(formed after root complition
without any external stimuli,
regular arrangement)
TYPES OF DENTIN

14. DENTIN
(formed after tooth eruption
due to external stimuli,
irregular in arrangement)
REPARATIVE DENTIN
SCLEROTIC DENTIN
REACTIONARY DENTIN

15. HISTOLOGY OF
DENTIN

16.  Thicker dentin seen in boys than girls of
similar age group and this increases during
puberty.
 The buccal surfaces of the tooth showed
maximum thickness, followed by lingual.
CLINICAL CONTENTS
Dentinal tubules branches, anastomoses to
form canalicular system enhancing carious
process.

17. INCREMENTAL GROWTH LINES
OF VON EBNER
 These lines reflect the daily
rhythmic, recurrent deposition of
dentin matrix as well as a hesitation
in the daily formative process.
 Theses lines situated about 20µm
apart.
 Run at right angle to the tubule.
 Deposit at 4 µm daily and
mineralize in a 12-hour cycle.

19. The contour lines formed from secondary
curvatures between neighbouring dentinal
tubules due to hypomineralisation known
as CONTOUR LINES OF OWEN
Prenatal and postnatal dentin are
separated by an accentuated contour line
known as NEONATAL LINE

20.  Between the
odontoblastic process and
the peritubular dentin,
periodontoblastic space
is present.
 This space contains
dentinal fluid which is
outward from the pulp,
having higher K+ and
lower Na+ content.
PERIODONTOBLASTIC
SPACE

21. • Hypomineralised dentin wherein globules
of dentin fail to coalesce into a
homogenous mass, appears dark in
transmitted light.
INTERGLOBULAR
DENTIN
• Prevalent with vitamin D deficiency or
exposure to high levels of fluoride at the
time of dentin formation.

22. Tomes’ Granular Layer
 In transmitted light, a zone adjacent to
cementum in root appears granular called as
TOMES GRANULAR LAYER (coalescing and
looping of terminal portions of tubules)
 This layer has highest concentration of calcium
and phosphorus, whereas Interglobular dentin
has higher concentration of sulfur.

23. HYALINE HOPEWELL-
SMITH LAYER
 Hyaline layer present outside
the granular layer(15-20 µm
wide)
 Nontubular and structureless.

24. The processes in tubules may
disintegrate or retract, leaving behind
an empty tubule, referred as DEAD
TRACT.
Reparative dentin protect the pulp
from infection by sealing off dead
tract.
Appear black in transmitted light.
DEAD TRACT

25. INNERVATION OF DENTIN
INTRATUBULAR NERVES-
 Nerves with close approximation with
odontoblastic process.
 Mostly located in coronal zone(pulp
horn).
 Synapse like relation seen between the
nerve and the odontoblastic process.
 The subodontoblastic plexus of
Raschkow seen in the cell-free zone of
Weil.

26. THEORIES OF PAIN TRANSMISSION
DIRECT
NEURAL
STIMUL
ATION
HYDRODYNAMIC
THEORY
TRANSDUCTIO
N THEORY
Nerves in
the dentine
get
stimulated.
Various stimulus effect
fluid movement in
dentinal tubules.
INWARD MOVEMENT-
due to cold stimuli
OUTWARD
MOVEMENT- due to
drying of exposed
dentinal surface.
The odontoblast
process is excited
by the stimulus and
the impulse is
transmitted to the
nerve endings in the
inner dentin.