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Enamel

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1. Describe the makeup of enamel: Hardest calcified tissue in the body. No nerves or blood supply. 96% inorganic material: hydroxyapatite. 3% H2O, 1% organic material: calcium phosphate/ phosphorus.
2. Define amelogenesis: Enamel matrix is aid down during the apposition stage of tooth development.
3. What is an ameloblast? Cells that will form enamel during amelogenesis.
4. Describe the stages of enamel maturation: Enamel is not a renewable tissue b/c ameloblasts disintegrate as the tooth erupts. AS the tooth matures, it matures in the incisal or occlusal surface of crown near DEJ, keeps overlapping & moves civically toward the CEJ.
5. Describe enamel rods: Enamel is made up of enamel rods, which are formed by ameloblasts, Considered to be the structural unit of enamel. Chewing impact of 20-30 lbs per tooth. Enamel is thickest over areas of greatest impact.
6. 4 ameloblasts produce: 1 enamel rod
7. 1 ameloblast produces: head of the rod.
8. 3 ameloblasts produce: tail of rod.
9. Describe lines of Retzius: Dark lines that indicate growth lines of enamel.
10. Imbrication Lines: associated with lines of Retzius. Ridges usually found in cervical 1/3 of tooth.
11. Perikymata: Grooves that are found on newly erupted anterior teeth & reduce with age due to wear.
12. Describe Hunter-Schregar bands: Dark & light bands that run perpendicular to DEJ caused by curvature of enamel rods.
13. Neonatal line: Line that marks in change of environment & nutrition at birth. All primary teeth & larger cusp of perm. 1^st molars.
14. Enamel spindles: Come from DEJ where dentinal tubules will penetrate the membrane into enamel.
15. Enamel tufts: Come from DEJ, extend outward to enamel, have space between enamel rods filled with organic enamel & they are tufts.
16. Enamel lamellae: Visible cracks on surface of enamel created during tooth function (chewing ice, etc.) or enamel formation. These cracks can be an avenue for dental caries.
17. Describe the mechanism of caries: Pit & fissures: occlusal: little incubators for plaque. Dentin & cementum is softer, acid seeps through & harms subsurface enamel first the on to occlusal.

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.