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Dentin Quiz

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1. Dentin is 70% calcium hydroxyapatite (inorganic), 20% organic, and 10% water.
2. Dentin is softer than enamel.
3. Dentin makes up the bulk of the tooth.
4. Define Dentinogenesis: The dentin matrix is laid down during the apposition stage of tooth development.
5. List the stages of dentin formation: primary & secondary.
6. Describe the stages of dentin formation:
   1. primary: balls of calcium hydroxyapatite formed & expanded & fused together. Run into each other.
   2. Secondary: partially mineralized area of hydroxyapatite that’s layered on top or within the initial primary stage. Incomplete fusion.
7. List the types of dentin: Mantle, intertubular, circumpulpal, peritubular.
8. Found between dentinal tubules: intertubular.
9. Located in outer pulpal wall, bulk of dentin in a tooth is this type: circumpulpal
10. First type that forms & matures within the tooth: Mantle
11. Creates wall of dentinal tubule: peritubular
12. The following are types of dentin, describe their formation:
    1. Primary dentin: 1^st formed. Formed in tooth before apical foramen. More mineralized than secondary dentin.
    2. Secondary dentin: forms after apical foramen and continue to form thru out life. Formed more slowly & less mineralized.
    3. Tertiary or repair dentin: forms immediately with injury or trauma, & seals off area. Schlerotic- chronic injury, highly mineralized. Tubules become empty of fluid & fill up from top to bottom. Can make root canal harder to perform.
13. What type of spread is found with the decay of dentin? Mostly horizontal
14. These lines show how dentin is laid down & deposited over days: Von Ebbners
15. These lines appear as a series of dark bands & show disturbance of metaboism (e.g Tetracycline): Lines of Owen
16. Zone that is underlying the cementum, covering the root: Tomes Granular layer
17. Describe dentin in older people: pulp chambers become smaller, root canals & dentinal tubules will become narrower. Blood & nerve supply decrease.

Disclaimer: These notes were copied and pasted from files sent to me by Andrea.  They have not been reviewed for errors. You are responsible for checking out the information to verify the accuracy. This site, Amy Nieves and Andrea are not responsible for typographical errors.