Dentine + Pulp Flashcards
Which tissue forms the bulk of the tooth?
Dentine
Which tissues of the tooth is dentine harder than/softer than?
Dentine is harder than bone and cementum, but soften than enamel
Dentine has greater compressive and tensile strength than enamel. What does this mean?
- Compressive strength: the ability to resist breaking under compression
- Tensile strength: the ability to endure tensile forces without breaking apart
Dentine is permeable. What does this mean?
Substances can move through it
What is the basic unit of dentine?
Dentinal tubules
Describe the content of dentine
- Hydroxyapatite (70% weight, 50% volume)
- Water (10% weight, 20% volume)
- Organic matrix (20% weight, 30% volume)
Which contains more organic matrix: enamel or dentine?
Dentine (20% compared to 1-2%)
Organic matrix gives dentine its compressive strength
Which direction does mineralisation occur in dentine?
Inwards
What is dentine between tubules called?
Intertubular dentine
What is intratubular dentine/peritubular dentine?
Dentine created after original tubule becomes smaller
What type of curvature is present in dentine?
Primary and secondary curvature
What are the boundaries of dentinal tubules?
Tubules run from the amelo-dentine junction to the inner portion of the pulp
Which cells form dentine?
Odontoblasts
Where are odontoblasts located?
Inside the pulp
What is predentine?
- Predentine is an organised matrix that hasn’t been mineralised yet
- Predentine is formed throughout your lifetime
Which is formed throughout your lifetime: enamel or dentine?
- Odontoblasts form dentine throughout your lifetime
- Enamel is only formed during embryo stage
Which process mineralises dentine?
Nucleation
Describe the contents of dentinal tubules
- Odontoblast processes
- Unmyelinated nerve terminals (sensory)
- Dendritic cells (immune cells)
- Dentinal fluid from the pulp
How does outer dentine differ from inner dentine?
Outer dentine contains more dentinal fluid. Mineralisation ocurs inwards.
Where are outer dentine and inner dentine located?
- Outer dentine: near amelo-dentine junction
- Inner dentine: near pulp
What is the dental pulp?
Connective tissue ‘core’ of the tooth
Describe the contents of the dental pulp
- Cells: odontoblasts, fibroblasts, defence cells
- Extracellular components: fibres (collagen, oxytalan), matrix (proteoglycans, chondroitin SO4, dermatan SO4)
- Nerves: sensory, autonomic (sympathetic)
- Blood vessels
- Lymphatics
What happens to the size of the pulp as we age?
- Less pulp presents, more dentine is formed
- Pulp chamber shrinks
What is the ‘cell free zone’?
Space between richly vascularised space and presence of odontoblasts
What do odontoblasts act as a barrier between?
The pulp and dentine formation
Blood vessels do not penetrate the odontoblast layer
What are the functions of the dental pulp?
- Nutritive, dentine growth, dentine repair, defence (immune cells, lymphatics), neural: sensory, control of dentinogenesis
Why doesn’t dentine bleed?
Blood vessels do not penetrate dentine
