Pulp Flashcards
Apical foramen size
.3 to .6mm
Odontogenic zone
And zone of weil
- it’s the odontoblastic + cfz +crz
- it’s the cell free zone
Cfz
Less prominent in root
Pulp outline follows the ….
Outer Dentin outline
Pulp organ definition
After dentin
production begins, It is now called the pulp organ.
Stages of fibroblast
Large multiple processes with Central nucleus, numerous synthetic organelles if young pulp.
• In aged pulp: appear smaller, flattened, spindle shaped with few organelles and termed FIBROCYTES.
• During degradation they have cytoplasmic granules and lysosomes and termed FIBROCLASTS.
Location of fibroblast
Loose network all over the pulp and more in crz
Junction between fibroblast?
At the processes junctions to processes of other fibroblasts.
Histiocytes
Definition: They are tissue-resident macrophages found in connective tissue.
➢ Function: • involved in elimination of dead cells during the turnover of dental pulp
•Remove bacteria and foreign bodies •Have immune roles during inflammation
➢ Site: located in the pulp center around blood vessels and capillaries. ➢ Microscopic picture: • Irregular in shape with short blunt processes and invagination of plasma membrane, small dark nucleus and granular cytoplasm.
• The distinguishing feature is aggregation of vesicles or PHAGOSOMES which contain phagocytosed dense irregular
Plasma cell
Microscopic picture: • Nucleus appears small and eccentric in the cytoplasm,
• The chromatin of nucleus is adherent to nuclear membrane and so give the cell the characteristic CART-WHEEL appearance.
Function: They are more seen during inflammation and their function is to produce antibodies.
Mast cell
Function: Their number increase during inflammation and they produce histamine & heparin.
• Microscopic picture: • They have a round nucleus and their cytoplasm contains many GRANULES.
• They are demonstrated by using special stains as TOLUIDINE BLUE.
Dendritic cells
Site: distributed largely around odontoblasts and central blood vessels.
• Microscopic picture : they have three or more main dendritic processes which branch.
• Function: they act as ANTIGEN PRESENTING CELLS stimulating the division and activity of native Tlymphocytes.
Other leukocytes
They are blood vascular elements that are found extravascularly in normal pulp
• Examples: neutrophils, eosinophils, basophils, and lymphocytes.
• Function: during inflammation they increase in number.
• In normal pulp T-lymphocytes are more present than B-lymphocytes.
تجميع للsites of pulp cells
- fb—crz and allover pulp
- stem— crz and pulp center around bv
- histiocytes — in center around bv and capillaries
- dendritic— center around bv and around odontoblasts
UMC
Function: • They represent the pool fromwhich the cells of the pulp are derived. • When need arises they may become odontoblasts or fibroblasts.
• Number: They are the primary cells in the very young pulp but decrease after root completion and in older pulp.
• Site: they are found in cell rich zone and pulp core and around blood vessels. • Microscopic picture: large, polyhedral in shape with peripheral cytoplasmic extensions, when side-viewed they appear SPINDLE-shaped.
• Mesenchymal Stem cells can be isolated from the pulp like: Dental pulp stem cells (DPSC) & stem cells from exfoliated deciduous teeth (SHED).
Change in pulp collagen with age
In young pulp: single fibrils of collagen are found scattered between the pulp cells.
• With age: the collagen content becomes organized into fiber bundles especially in the most APICAL PORTION of the pulp.
Why engage the pulp apically
Clinical tip: During endodontic ttt it’s better to engage the pulp at the apical region rather than coronal to prevent tissue tearing.
Is there elastic fibers in the pulp
Only in wall of large blood vessels
Chondroitin and hyaluronic acid in pulp?
During early development, chondroitin A&B and hyaluronic acid has been demonstrated in abundance.
Pulpal blood flow
is more rapid with higher blood pressure than in most areas of the body.
Arterial plexus in pulp is
Sub odontoblastic parietal capillary plexus
Lymphatic of pulp special stain and shape
Lymph vessels are best examined by Iron hematoxylin stain. • Branched vessels appear as H, Y or I shaped.
Relation between lymphatic of pulp and pdl
Lymph vessels draining the pulp & periodontal ligament have a common outlet.
Nerves in the pulp Type Arrangements Stain Time of development Most found in ...
As the myelinated nerves run longitudinally, they give off side branches as free nerve endings that terminate in a subodontoblastic plexus known as PLEXUS OF RASHKOW or PARIETAL LAYER OF NERVES.
•This plexus is more prominent under pulp horns. • It is not evident until the tooth has erupted. •A small numbers of nerve fibers lose their Schwann cell coating and pass between the odontoblast cell bodies and dentinal tubules. •Silver stain is used to demonstrate nerve fibers.
Pulp is richly innervated (What nerves?) • Nerves enter the pulp through apical foramen along with afferent blood vessels and together form neurovascular bundle.
• Two types of nerve fibers are present: 1. Non myelinated sympathetic nerves that supply large muscular blood vessels to function in contraction or dilatation of blood vessels.
2. Myelinated sensory nerves of trigeminal nerve which can not differentiate between heat, touch, pressure or chemicals. This is because the pulp has only PAIN RECEPTORS (NOCICEPTORS).
Clinical consideration of the pulp
Q1) Dental Pain is diffuse while periapical pain is localized?
Due to absence of MECHANORECEPTORS
Q2) Can dental pain be referred to the opposite side?
No, pain may be referred to the same side only but doesn’t cross the midline
Clinical tip: During endodontic ttt it’s better to engage the pulp at the apical region rather than coronal to prevent tissue tearing.
Clinical tip: Accessory canals may be a source of transinfection between pulpal and periodontal tissues causing periodontic-endodontic lesions.
Clinical tip: Knowledge of anatomy of pulp chamber and horn locations is essential in operative dentistry to avoid pulp exposure especially in young age
Q1) Sometimes, in irreversible pulpitis , hot drinks aggrevate the pain while cold drinks may relief it?
Because heat causes expansion of gases and blood vessels while cold causes contraction.
On lying down, dental pain increases? pulpal blood pressure and pressure on nerves increases as well.
Sequelae of pulp infection
Orthodontic forces may cause damage and inflammation to the pulp.
Pulp tests like …..and Teeth may have damaged nerves (no and response to sensitivity tests) BUT normal blood supply so it is completely viable (e.x. traumatized teeth)
Pulp capping
Age changes of pulp
-Vascularity: vascular supply decreases with calcification in blood vessels walls (atherosclerosis)
-Size: ❖Size of pulp chamber, horns & root canal decreases or becomes completely obliterated.
❖The apical foramen is narrowed. ❖This may cause reduction in the vascular supply of the pulp.
Sensitivity: Loss & degeneration of myelinated &non myelinated axons …… reduction in sensitivity.
Fibrosis of pulp
❖Collagen synthesis and degradation rates are diminished.
❖Fibrils become arranged as bundles
❖With decreased cell number and pulp size …pulp looks apparently more fibrous.
Cellularity: cells decrease in activity & number especially progenitor cells leading to reduced reparative functions
Diffuse pulp calcification
They are irregular calcific deposits in pulp tissue. ❖ Site: Commonly occurring on top of hyaline degeneration in the root canal and not common in pulp chamber.
❖ Structure: ❖ Mostly fine, amorphous calcified spicules with no specific structure
❖ They follow the course of blood vessels or collagen bundles or as dystrophic calcification.
Diff in location of diffuse and localised calcification
Diffuse —-root
Localized—-root or crown
Diff between true and false pulp stone
-true ..apical ..small ..dentinal tubules and odontoblasts ..less common .. Remnants of epithelial root sheath of Hertwig invade pulp tissue leading to differentiation of UDMCs of pulp to odontoblasts forming irregular masses of dentin
- false
Degenerated cells, areas of hemorrhage or thrombi act as central nidus favoring deposition of concentric layers
