OE L6 Dentine Pulp Complex Flashcards
What does pulp contain?
- Loose connective tissue
- Cells
- Nerves
- Vascular supply
Give 5 functions of the pulpal organ.
- Blood supply and nutrition to odontoblasts
- Sensory function, extremes in temparute, pressure or chemical insult
- Defensive function, immune-inflammatory response
- Cells for reparative dentine formation
- Regulation of dentine formation through signalling factors e.g. cytokines
Describe dental pulp organisation.
- Blood vessels and nerves enter and exit through apical formaen
- Each root has at least one canal
- Vessels and nerves become more narrow and branched as they reach the coronal portion of tooth
- In bifurcation zone there are accessory canals called foramina which directly interact with adjacent tissues e.g. periodontal ligament
Describe the dentine-pulp interface.
- Organised layer of odontoblasts adjacent to pulp
- Odontoblasts have strong interactions with cells of pulp and ECM
- Directly beneath odontoblast layer is cell free zone/zone of Weil, a thin layer almost completely devoid of cells
- Beneath cell free zone is cell rich zone
Are there variations in odontoblast structure in the tooth?
Yes.
- Cell size and shape varies depending on tooth region, columnar in crown, cuboidal in mid-root, flattened in apex
- Odontoblasts are smaller near root region
Useful to remember when looking at histological sections to know which part of the tooth you are viewing.
- Cell size and organelle content also reduce with age
What are the 3 types of junctions odontoblasts possess?
- Tight junctions and intermediate junctions between odontoblasts themselves, and between odontoblasts and cells of pulp
- Gap junctions to support orientation of odontoblasts
What organelles are found in the odontoblast cell body?
- Nucleus and mitochondria in periphery
- Organelles involved in translation, packaging and secretion of proteins found in forefront of (golgi, RER, mitochondria)
What is the most abundant cell type in pulp?
Pulpal fibroblasts.
- Younger fibroblasts are more rounded and pulp
- Older are flattened with dense nuclei
What other cells are important in pulp?
Undifferentiated mesenchymal stem cells
What is the role of undifferentiated mesenchymal stem cells?
- Respond to cytokines and growth factors to form new fibroblasts, odontoblast like cells and endothelial cells
- Role in dentine and pulpal repair
Where are undifferentiated mesenchymal stem cells found?
- Cell rich zone (odontoblast like cells)
- Central pulp (fibroblasts)
- Surroudning blood vessels of pulp (enfothelial cells)
All undifferentiated mesenchymal stem cells are of neural crest origin
What is the role of fibroblasts?
- Produce cytokines, growth factors and inflammatory mediators in response to trauma and injury
- Stimulation of reactionary and reparative dentine formation
- Remove damaged ECM components from pulp and replace with newly synthesised and secreted matrix components
Describe the fibrous components of the pulpal matrix.
- Predominantly type 1 collagen, provides strength and protection
- Collagen type III, V and VI
- Oxytalan fibrils
- Elastin in blood vessel walls providing elasticity
Describe the non-fibrous components of the pulpal matrix and their role.
- Proteoglycans: decorin, biglycan, versican and syndecan
Regulate cell signalling, matrix assembly, cell migration, cell proliferation and inhibit mineralisation.
- Glycoproteins: fibronectin, laminin and tenasin
Roles in matrix formation, cell attachment and cell migration.
Which cells act as the first line of defence for the pulp?
Dendiritic cells.
- Initial detection and response to trauma/disease
- Initiate primary immune response
- Capture and present foreign antigens to T-cells
- Increased number of dendritic cells in carious teeth
