Exam 2 Flashcards
Percentages of dentin:
Mineral: ?
Organic: ?
Water: ?
Mineral: 70%
Organic: 20%
Water: 10%
How does Type 1 Collagen of dentin differ than that in bone?
- higher ratio of proline and hydroxyproline
- Higher prevalence of molec crosslinking
- more bound to water
What structure located in what part of the enamel organ stimulates osteoblast differentiation?
fibronectin in the basal lamina of inner enamel epithelium
What are the four growth factors secreted by the IEE?
- Transforming Growth Factor (TGF)
- Bone Morphogenetic Protein (BMP)
- Insulin-like Growth Factor (IGF)
- Fibroblast Growth Factor (FGF)
How thick is mantle dentin?
50-100 micrometers
What are lines of von Ebner?
hesitation in matrix formation every 4-20 days that show has hypomineralization of dentin
Dentin tubule diameter at pulpal surface vs the DEJ?
Pulpal surface: 2.5 micrometers
DEJ: 0.9 micrometers
What is bad about interglobular dentin? Where is it often found?
- nothing wrong, formed by hypomineralized area in between normal areas
- in dentin in crowns
What is Tome’s Granular Layer?
-granular appearing layer of dentin adjacent to cementum
Define primary and secondary dentin
Primary: dentin (except mantle dentin) formed up to the time of functional occlusion
Secondary: dentin (except tertiary dentin) formed after tooth achieves functional occlusion
Where does tertiary/reparative dentin come from?
-subodontoblastic layer
Where do the growth factors that affect the subodontoblastic layer come from?
the pulp
What condition lead to bluish opalescent teeth with normal enamel?
Dentinogenesis imperfecta
What condition can lead to teeth having no pulp chambers?
Dentinogenesis imperfecta
What does fluoride replace in hydroxyapatite crystals?
hydroxyl ions
What are the 5 bacteria thought to be responsible for caries?
- Streptococcus mutans
- Streptococcus sorbrinus
- Streptococcus gordonii
- Lactobacillus acidophilus
- Actinomyces viscosus (root caries)
What teeth are most commonly affected by dentinal sensitivity?
Canines and premolars
The Brannstrom’s Hydrodynamic Theory of dentin sensitivity is based on what law of physics?
Charles’ Law (volume of gas or liquid is directly proportional to heat applied at constant pressure
At what stage of tooth development does pulp start forming?
Cap Stage
When do capillaries start developing in the pulp?
Bell Stage
What is the origin of pulpal cells?
Ectomesenchymal neural crest cells
What are the two compartments of the pulp?
What is in each compartment?
- Odontogenic Zone: odontoblast cell layer, cell-free zone of Weil, Cell-rich zone, parietal plexus of nerves (Raschkow’s plexus)
- Pulpal Core: Fibroblasts, Type I and II collagen, extracellular matrix, blood vessels, nerve tissue
What are the functions of dental pulp?
Embryonic induction, formative, protective, reparative
What are the non-collagenous matrix components of pulp?
- proteoglycans
- glycosaminoglycans
- phosphoproteins
- glycoproteins
- gamma-carboxyglutamate-containing proteins
What CN branch innervates the pulp? (sensory and motor)
CN V (Trigeminal)
What are the classifications of the sensory nerve fibers ni the pulp?
- fast: A-delta for sharp pain, large diameter
- slow: C for dull pain, narrow diameter