Biological Factors (Melfi) Flashcards
T or F: dental-pulp all junction is always changing
True
What are the two most bio- compatible tissues of a tooth?
Dentin and pulp
What embryological germ layer do oral tissues arise?
Ectoderm
What histological tissue type is dentin and pulp?
Connective tissue
What type of tissue is enamel?
Hard derived epithelial tissue
What are the four classic pulp tissue functions?
- Formative: produces dentin
- Nutritive: nourishes a vascular dentin
- Protective: carries nerves that give dentin sensitivity
- Reparative: produces new dentin due to external stimuli
What tissue helps maintain dentin as a vital tissue?
Pulp
What is the chemical composition of dentin?
70% inorganic hydroxyapatite
20% organic mostly collagen type 1
10% water
What percent of enamel is inorganic?
96%
What is contained in the dentinal tubules?
Odonoblast processes and tissue fluid
Where is the nucleus of the odonoblast located?
In pulp
What cell secretes dentin?
Odonoblast
What is the hardest part of dentin?
Peritubular dentin: wall of tubule
What is the softest dentin?
Predentin
What makes up the composition of pulp?
- different cell types
- extracellular substance (organic): type 1 collagen (90%)
- tissue fluid
- blood vessels, lymph vessels, nerve fibers
What is the origin and function of tissue fluid?
Origin: blood supply
Function: conveys nutrients and metabolites to pulp and dentin
What are the two classes of extracellular substance in pulp?
- Fibers: type 1 collagen (90%)
2. Non-fibrous (ground substance): glycosaminoglycans, glycoprotein
What cell type belongs to both pulp and dentin?
Odontoblasts
What are the four cell types in pulp?
- Odonoblasts ( most prominent cell of dental pulp)
- Fibroblasts (most numerous cell in pulp tissue)
- Defense cells: macrophages and dendritic cells
- Undifferentiated mesenchymalmcells (stem cells)
What cell secretes and loses the extracellular substances?
Fibroblasts
What is the first tissue to show up in a developing tooth?
Dentin
What is the predentin layer?
Unmineralized dentin secreted by Odonoblasts
The dentinopulpal junction forms what?
Tight junction
What is the current theory of tooth pain?
Hydrodynamic theory- when cut, the tissue fluid is disturbed and current travels to nerve for pain
T or f: there are nerves in dentin?
False
What are dead tracts of dentin?
Empty dentinal tubules filled with air that does not transmit pain
What is reparative dentin?
Reactive. It’s produced by Odonoblasts directly after stimulus. It is formed under the stimulus at the pupal surface of dentin
What is sclerotic dentin?
Transparent dentin. Deposition of mineral salts within dentinal tubules-> tubules obliterated.
What is one major reason reparative dentin is made?
To protect the pulp
From external to internal, order the following: Dead tract dentin, sclerotic dentin and reparative dentin.
External: sclerotic ( closest to stimulus)
Middle: dead tract
Internal: reparative
What are pulp stones?
Ectopic mineralizations with in pulp tissue
T or f: a young tooth has a bigger pulp chamber than a old tooth?
True
