Pulp Biology (Exam I) Flashcards
Dental papilla
- AKA dental pulp
- Originates from dental lamina
Describe the sequence of Odontogenesis?
- Dentinogenesis occurs before amelogenesis
- Tooth forms from the inside out
What does the Dental sac form?
Forms the alveolar bone and periodontium originates
Dental pulp originates where?
Originates from immature mesenchymal tissue
Bell stage; the dental papilla at 10 weeks
Describe Root formation?
- Forms from cervical loop
- AKA epithelia diaphragm Hertwigs root sheath
- Dental papilla enclosed by the inner and outer enamel epithelium
- Inner and outer enamel epithelium join to form the epithelial diaphragm or the cervical loop to form the future cemento-dentinal junction
Describe the Cell rests of Malassez?
- Epithelial root sheath breaks up.
- Connective tissue of the dental sack contacts dentin and forms cementoblasts and the periodontal ligament.
- Some epithelial cells remain in the periodontal ligament as cell rests of Malassez.
- Residual epithelial cells from root sheath can form a lateral periodontal cyst which are typically benign
Describe Lateral and accessory canals
- Two routes of formation
- Direct contact between pulp and periodontal ligament
-Formed by a break in the root sheath before dentin is formed or a blood vessel traveling between the dental sac and the dental papilla
Accessory canals located in
- Furcation
- Apical 1/3rd
Lateral canals located in
Coronal 2/3rd
Lateral and accessory canals contain
- Connective tissue
- NO odontoblasts or pulp tissue
Describe The Apical foramen
- Pulp contacts PDL at apex and is offset .5 to 1 mm.
- Contains neuromuscular bundle.
-Can be a delta, an apical foramen with several accessory canals.
-In mature tooth, size varies from .3 to.6 mm.
CHANGES because of cementum deposition
Note: Caries is most common pathology resulting in endodontic treatmen
Describe the Histology of the pulp
- Pulp is a form of connective tissue
- Pulp is in a non-compliant environment
- It is surrounded by rigid walls of the tooth
- It cannot swell in response to infection
Cells of the healthy pulp contain what?
1) Fibroblasts (MOST COMMON)
2) Mesenchymal Cells
3) Odontoblasts
4) Histocytes
5) Dendritic Cells
6) Lymphocytes
Describe Fibroblasts
1) most common cell in the pulp
2) Form type I and III collagen
3) Form ground substance
Describe Odontoblasts
- Form dentin
- Columnar cells in crown
- Cuboidal in midroot
- Squamous at apex
- Forms dentin, type I collagen
- Highly specialized
- Cell body and Tomes Process
- Odontoblastic process to DEJ
Describe Defense Cells
Cells associated w/ a inflammatory response as seen in the pulp as a result of a irritant
Describe the Fibers?
- Pulp contains collagen.
- Type I is in dentin, secreted by the odontoblast
- **Type I and III secreted by fibroblast and are in pulp.
- No elastic fibers.
- Apical region contains most collagen.
Describe the Exteracellular Matrix
- Water
- Glycosaminoglycans
- Collagen (I, III)
- Non-Collagenous Proteins
- Tenascin
- Fibronectin
- Substrate adhesion glycoproteins
- Involved in the attachment, spreading and migration of cells
- Medium for transport of nutrients and oxygen
Describe the Pulpal “ Afferent Sensory “ Nerve Supply
A-Delta fibers (pain fibers)
1) Low stimulation threshold
2) Myelinated
3) High conduction velocity
4) Pulp-dentin border
5) Sharp lightening type of pain
* *REVERSIBLE
C fibers
1) High stimulation threshold
2) Non-myelinated
3) Low conduction velocity
4) Distributed thru central pulp
5) Throbbing dull, lingering
* *IRREVERSIBLE PULPITIS
Describe the Pulpal “ Efferent Motor” Nerve Supply
Smooth muscle of the capillaries
Sympathetic
Parasympathetic?
Nerves extend only 100 to 200 microns into the dentin
What are the 3 Theories of dentin sensitivity?
1) Direct Innervation
Nerve fibers in tubule
2) Odontoblastic Receptor
Nerves and odontoblasts are close
3) Hydrodynamic
Pulpal fluid movement in tubules triggers nerves
Accepted theory, correct answer for board
*MOST COMMON
Describe the Blood supply to the pulp
-Internal Maxillary artery:
“Main blood supply of the pulp”
1) Posterior superior alveolar artery
2) Middle superior alveolar artery
3) Anterior superior alveolar artery
4) Inferior alveolar artery
5) Arterioles enter thru apical foramen and lateral canals, course toward crown
6) Most numerous in the subodontoblastic zone
Describe the Venus return of the pulp?
1) Pterygoid plexus and Internal maxillary vein
2) Veins are larger, not innervated
3) A-V shunts in pulp
- Regulates blood flow
- Defense mechanism for inflammation shunting blood from artery directly to vein bypassing capillary within tooth
4) Exit thru apical foramen and lateral canals
5) Thin walled
6) Blood flow is greater in coronal pulp
Lymphatic vessels are also present in the pulp
What are the Functions of the pulp?
1) Induction- Produces predentin
Stimulates the initial formation of ameloblasts
2) Formation- Continuously forms secondary dentin
Most important function
Normal physiological process not in response to irritation or injury
3) Nutrition- Dentinal fluid nourishes dentin
4) Defense- Forms reparative dentin
5) Innervation- Innervates dentin
