Dentin Pulp complex Flashcards
Dentin between roots is said to be?
Interadicular
What are the 3 junctions of a tooth?
1-DEJ
2-CEJ
3-CDJ
Dentin is very similar (analogous) to what other tissue?
Bone
Dentin is ____% inorganic ______% organic and _____% water
70, 20, 10
90% of the organic material in dentin is made up of what?
Collagen (mostly I, some III and V)
Which 5 non collagenous proteins in dentin are also found in bone?
1-Bone Sialoprotein (BSP) 2-Osteopontin (OP) 3-Osteocalcin (OC) 4-Osteonectin (ON) 5-Matrix extracellular phosphoglycoprotein
Which two non collagenous proteins in dentin are dentin specific?
1-Dentin matrix protein-1 (DMP-1)
2-Dentin Sialophosphoprotein (DSPP, cleaves into 3)
What 3 proteins result from cleaving of DSPP?
1-Dentin Sialoprotein (DSP)
2-Dentin phosphoprotein (DPP)
3-Dentin Glycoprotein (DG)
Cleaved from the N terminus of DSPP by BMP-1, which dentin protein is a proteoglycan, is similar to DMP-1, is expressed in dentinal tubules and may act to prevent mineralization?
DSP
*loss of this results in harder, more brittle dentin
Cleaved from the middle of DSPP by BMP-1, which dentin protein is a glycoprotein and has an unknown function?
DGP
Cleaved from the C terminus end of DSPP by BMP-1 which dentin protein is attached to collagen, binds lots of Ca+2, and is not thought to be glycosylated?
DPP
*loss results in not as hard dentin
DSPP can cause dentinogenesis imperfecta in what two ways?
1-Type II- pulp chamber fills in
2-Type III- pulp enlarges, hypo-mineralization
*Type I results from osteogenesis imperfecta where collagen I has a defect
odontoblasts have what origin?
Mesenchymal
What junction has a scalloped architecture?
DEJ
For what two reasons is the DEJ critical?
1-Defines the shape of the crown
2-Keeps dentin attached to enamel (resist shearing)
The first layer, closest to the DEJ is called?
Mantle dentin
Collagen III fibrils, 0.1-0.2 mm in mantle dentin, are associated with fibronectin and are called what?
Von Korffs fibers
Odontoblasts extending into the developing matrix and secreting dentin through matrix vesicles are called what?
Tomes Fibers
What are the two types of matrix mineralization?
Gloublar (like paintballs)
Linear (mineralizing wall)
Non collagenous proteins regulate tubular primary dentin played down after DEJ formation, this dentin is called?
Circumpulpal
*mantle dentin is therefore NOT tubular
What initiates odontoblast differentiation at the roots?
HERS
What are the 3 types of dentin?
1-Primary dentin (formed during development)
2-Secondary dentin (formed after root formation and throughout life)
3-Tertiary dentin (response to insult, is more like bone)
When the trauma does not damage odontoblasts what subtype of tertiary dentin forms?
Reactionary dentin
When trauma damages odontoblasts, causing the recruitment and differentiation of new odontoblasts what subtype of tertiary dentin forms?
Reparative dentin
What are 3 main strucutures in dentin?
1-Dentin tubules (with OD process)
2-Peritubular dentin
3-Intertubular dentin
What are the 4 histological zones of the pulp?
1-Odontoblast layer
2-Cell free zone of Weil (blood vessels and nerves)
3-Cell rich/dense zone
4-Pulp core
What is the soft connective tissue matrix of the pulp made up of?
- Collagen III mostly, some collagen I
- proteoglycans and glycoproteins
*collagen content increases with age
What are the 5 main proteoglycans found in the pulp?
1-Chondroitin-6-sulfate 2-Chondroitin-4-sulfate 3-Heparin sulfate 4-Dermatan sulfate 5-karatan sulfate
What holds the layer of odontoblasts together and makes them only slightly “leaky”?
Adherents junctions (tight junction, desmosomes, zonula adherens)
*serum proteins can pass, can form gap junctions with fibroblasts as well
What is sequestered by the ground substance and is released when dentin is etched?
Growth factors
*GFs in dentin matrix recruit new OD
What is the predominant cell type found in the dentin-pulp complex?
Fibroblasts
*mainly found in the pulp core and cell rich zone and produces/maintains matrix of pulpal tissue
Why type of progenitor cells are present in the dental pulp?
Mesenchymal
Macrophages are part of the ______ immunity in dental pulp while dendritic cells are __________ immunity
Innate, acquired
*Dendritic cells under odontoblast layer.
The capillary network in the dental pulp is found in what region?
Cell free zone
*during primary dentin formation it is present in the odontoblast layer
Where do arteries and veins enter and leave the tooth?
Apical foramen
*nerves and lymph enter and leave here too
The network of nerves under the odontoblast layer especially in the coronal pulp is called what?
Plexus of Raschkow
What two types of nerve fibers are in the pulp?
1-Afferent nerves from the trigeminal (pressure/nociception)
2-Sympathetics from superior cervical ganglion (vascular control)
Nerve bundles consist of what two types of axons?
1-Myelinated “Ad” (sharp)
2-Unmyelinated “C” (throbbing)
*Myelination decreases as fibers proceed toward coronal pulp
What are the 3 proposed models for dentin sensitivity?
1-Direct innervation
2-Odontoblast nociception
3-Tubule fluid conductance (hydrodynamic)
More prevalent after 50 years of age, what pulpal feature is mineralized tissue formed in the pulp and occur around collagen fibers, dead cell aggregates or thrombi?
Pulp stones
