Please enable JavaScript.
Coggle requires JavaScript to display documents.
(3) Dentine-Pulp Complex (Pulp (Structure Organization (1) Pulp Core, 3)…
(3) Dentine-Pulp Complex
General Dentinal Properties
Tubular
Hydrated (Dentinal Fluid; transduate of ECF from pulp)
Apatite Crystals
Collagen Matrix
Whole Story/Dentinogenesis
Pre-Secretory
1) IEE in
Bell Shape
2) IEE signalling molecules
3)
Signalling
molecules
Dental Papilla
to
Odontoblast
4) Odontoblast
form Mantle Dentine
(Collagen fibres then mineralization)
9)
IEE
to
Secretory Ameloblast
5) Odontoblastic process forms (
Tome's Fibre
)
6) Odontoblast moves towards pulp; form
Circumpulpal Dentin
7)
Mantle Dentin
has no dentinal tubules;
8) unmineralized portion of cicumpulpal (pre-dentin)
Secretory
1)
Initial Dentine (Mantle Dentine)
stimulate
Ameloblast
to produce
Enamel Matrix
3)
Ameloblast
develops
Tome's Process
2)
Immature Ameloblasts
(without Tome's Process) dump
Initial Enamel
mineralized immediately (
No enamel rods
)
4) Final Enamel (Middle / Rod + Inter-Rod)
5) Last bit of enamel (
No enamel rods
)
Maturation Phase
1)
Apoptosis
of Ameloblasts
2)
Degradation of matrix
by
enzymes
3)
Minerals pumped out
Physical Structure
Types of Dentine
Primary
Rate: 4um/day
Develops until root/enamel starts developing
Secondary
0.4um/day
After root/enamel develops, odontoblast downregulated
Tertiary
Reparative (New Odontoblast)
Death of original odontoblasts
New odontoblastic cells from mesenchymal cells
Reactionary (Upregulated Old Odontoblast)
Local
Small, slow progressing
Upregulation of odontoblast
Sclerotic Dentine
Occluded by whitlockite crystals
Transparent dentin
:
Sclerotic / Calcified tubules (appear transparent)
Types of Dentine (Developement)
Root:
4)
Granular Layer of Tomes
: Hypomineralized
5)
Hyaline Layer of Hopewell Smith
Facilitate adhesion of cementum to dentin
Produced by Hertwig's Epithelial Root Sheath (HERS - enamel organ)
Enamel like material
Crown:
4)
Mantle
: First formed dentin / Outer dentin (Adj to enamel)
Fibrils perpendicular to EDJ
No tubules
Mineralized by
matrix vesicles
(alkaline phosphotase/annexin - collects PO4 & Ca respectively)
Higher protein content, immediate mineralizaed
General Layers
1) Predentine: immature uncalcified; fibrils perpendicular to cell processes
2)
Circumpulpal
: Inner dentin (Adj to pulp)
3)
Interglobular
: Incompletely calcified dentinal matrix
P-C-I-M-T-H
Morphological Structure
Tubules
Inter-tubular (Between tubules)
Quantity: Most at EDJ decreases to Pulp
Reason: Tubules narrower at top
Less calcified
Mantle Dentine, First Formed (No Tubules)
Weaker: No calcification
Scallop-concavity
at
EDJ
(only for humans)
Increase SA for bonding
Reduced stress at EDJ
Peritubular / Intra-tubular Dentin
Quantity: Most at EDJ decreases to Pulp
Reason: More time to calcify
Less dense / More permeable closer to pulp
More calcified
Responsible for anisotropy (stress)
Fenestrated, fluid & ions odontoblastic process (ECF)
Incremental
Von Ebner's Lines (Short period lines)
Odontoblasts taking rest
daily
Like Enamel Cross Striations
Andresen Lines (Long period lines)
Odontoblast taking break
weekly
Use to calculate age at death
Like Enamel Lines of Retzius
Histological Bands
Schreger Lines (Primary)
Coincidence of sigmoid peaks
Visible with magnification
Contour lines of owen (Secondary)
Composition
Organic (20%)
Collagen 1
Collagen 3,5
DPP/DSP/DSPP
Osteonectin/Osteopontin
GLA Protein
Inorganic (70%)
Water (10%)
Odontoblast
Structure
Junctions between Cells:
Gap Junctions: Signal ions
Tight Junctions: Barrier pulp dentine
Intermediate Junctions: Integrity of odontoblastic layer
Difference between Bone & Dentine:
Dentine, calcification in gap junctions
Harder than bone
Function
Neurosensory
Secretes Dentine
Defense (Dentinal Fluid)
Clinical Implications
Aging
Dentin
Tubules narrow (homogeneously)
Difficult to locate pulp
Pulp
Less volume (secondary dentin reduce size)
Less cellular (Fibro/Odonto/Mesen/Immun)
Less innervation / vascular supply
Fibres increase / Fibrosis
Pulpal calcification
Ondotoblast downregulated
Factors affecting Dentinal Strength
Hydration (dissipate occlusal forces)
Occluded dentinal tubules
Root canal
Lower BP
Peritubular anisotropy
Pathogenesis
Dentine Dysplasia
Abnormal dentine production
Dentinogenesis Imperfecta
Impede calcification
Pulp
Structure Organization
1) Pulp Core
3) Cell Rich (Subodontoblastic layer)
4) Cell Free (Zone of Weil)
2) Plexus of Raschkow (Nerves)
5) Odontoblasts
C-N-R-F-O
Supporting Structures
Innervation
Apical foramen
Plexus of Raschkow
Fibres terminate between odontoblasts
Myelinated A, Unmyelinated C
Blood Supply
Apical foramen
Branching subodontoblastic capillary plexus
Microcirculation / Precapillary spincters
Lymphatic
Removal of high molecular weight solutes from fludid
Cells
Odontoblasts (Synthesize Dentin)
Fibroblasts (Synthesize ECM; Most common)
Dendritic cells/Macrophages/Lymphocytes
Undifferentiated mesenchymal cells (
Differentiate into Fibroblast / Odontoblasts
) eg. Reparative Dentin
AKA. Epithelial cell rests of Malassez
ECM
Collagen
Elastin
Fibronectin
GAG/PG
Function
1) Inductive
2) Formative
3) Nutritive
For dentin formation
4) Protective
Highly innervated
All stimulus sensed as pain
5) Defensive
Dentinal fluid outflow (Immunoglobulins)
Inflammatory response
