510-10 Flashcards
Review of embryology: which part of the ectoderm does enamel come from? What about dentin?
Enamel:the surface ectoderm Dentin:neural crest cells from the ectoderm
What is the thickened band at the outside of the maxillary and mandibular processes? What is the underlying tissue?
The PRIMARY epithelial band. Ectomesenchyme ((ectoderm + messderm)) (also found in pulp!) is below the basal lamina of the primary epithelial band.
Which cartilage structure sits below the ectomesenchyme of the MANDIBULAR arch?
Meckel’s Cartilage :)
What is the clone model of tooth formation? What is the field model?
FIELD:Distinct, graded, overlapping fields of ectomesenchymal cells for each tooth family CLONE:Each tooth family is derived from a clone of ectomesenchymal cells.. Its probably a MIX of the two theories. ALL IN ALL they form in a wave.
What are the two formations of the primary epithelial band growing down into the ectomesenchymal cells? When does it happen in the embryo?
The vestibular lamina (space between cheek and gingiva) and the Dental Lamina (teeth) Its about 6-7 weeks of embryo.
What is ANOTHER name for the primary epithelium as it invaginated into the ectomesenchyme making the dental and vestibule lamina?
The ORAL epithelium
If the dental lamina forms the enamel, what forms the dentine and the pulp?
The dental papilla-cresent shaped condensation of ectomesenchymal cells below the dental lamina
What cells develop out of the thick “bud” in between the dental lamina and the ectomesenchyme? When is this BUD stage?
The ameloblasts! At 8 weeks, right at the cut off of embryo and fetus!
What three structures arise out of the CAP stage?
The enamel organ (or CAP) has 1)Outer enamel epithelium 2)Inner enamel epithelium-closing around the dental papilla and 3)Stellate Reticulum-STAR shaped cells that draw water into the enamel organ
What do cusps start out as in the cap stage? What are four genes that drive this process?
Enamel knots (group of cells on the Inner enamel epi and Stellate Reticulum)….Shh, Fgf, Bmp, Wnt
How is the developing tooth freed from the epithelium?
The degeneration of the dental lamina
How is Crown pattern established?
Folding of the INNER enamel epithelium. IEE also has Ameloblasts!
What cells differentiate from the ectomesenchyme during the Bell stage?
Odontoblasts!
What two layers of the enamel organ make the cervial loop of the bell stage?
Inner Enamel Epi and Outer Enamel Epi
What does the enamel knot of the cap stage develop into at the bell stage?
The knot (future cusp) develops into a cord.
What gives the beautiful contours of the crown?
Differential rates of mitotic division of the inner enamel epi. COOL!
What irregularity during the bell stage leads to enamel pearls, odontomas, and supernumerary teeth?
A failure of cells to degenerate after the fragmentation of the dental lamina.
What identifies the apposition stage?
The production of enamel and dentin.
What is the collar of odontogenic epithelium formed when the IEE and OEE epithelia fuse? What part of the tooth does it develop? Hint another name: Painful hair..
Hert-wig’s epithelial root sheath. Will develop the apex of the root…
Which lamina is responsible for the development of the permanent tooth?
Succedaneous lamina (forms once enamel of primary tooth forms)
Do ameloblasts or odontoblasts differentiate first?
Ameloblasts, but dentin is made first. Confused?!?
What is the sequence for dentin and enamel being made?
Ameloblasts differentiate–>Odontoblasts Differentiate–>Dentin is made–>Dentin touches the ameloblasts and enamel is then made–>the Stellate Reticulum is forced away by the enamel
When are Audra’s baby’s permanent teeth going to develop?
Between week 20 of fetal development and ten months after birth. BUT some teeth take longer. Wizzies up to 5 years to Develop (not talking about eruption)
What cellular components are important in ameloblasts?
Lots of mitochondria, E.R.’s and Golgi’s. Making lots of protein scaffolding!!
What are the three stages of ameloblast production? Where do we start to see TOMEs process?
1)Presecretion-protein production 66% Protein 2)Secretion-Beginning of TOMEs process 93% Mineral 3)Maturation-More mineral ions to harden previously laid enamel 95% mineral
What are the main proteins involved in enamel formation? (Different codes on X and Y!)
90 % Amelogenins
What are the less popular enamel producing proteins? (10%)
Nonamelogenins: AMELOBLASTIN-ameloblast ADHERENCE to enamel surface like scratching the beaker to get crystals; ENAMELIN-for crystal elongation; TUFTELIN-esoteric, no known function.
What process on the ameloblast secretes enamel?
TOMEs process
Does the ameloblast spend most of its time in the ruffled or smooth stage? Which stage has more Mitochondria?
80% Ruffled-More Mitochondria DEPOSIT; 20% smooth ABSORB
What are shallow periodic furrows on the outer surface enamel called? Who named their striations?
Perikymata “PERRY-KAI-MATA”; Striae of RET-ZI-US
Which type of collagen fiber is most present in predentin? Who got to name these ones? hint: dutch Korff Are these fibers found in fully developed teeth?
Type I collagen, von Korff’s fibers. No, Only found in developing teeth!
Which anti biotic creates a pattern of incremental lines in DENTIN, like the striae of Retzius in enamel?
Tetracyclene
Is enamel translucent or transparent?
Translucent! Shows dentin underneath..
Which is less ordered: globular calcification or linear calcification?
Globular calcification occurs in irregular patches
Which is more mineralized? Peritubular or inter tubular dentin?
Peritubular!
What are the three cells that produce alveolar bone, PDLs, and cementum respectively?
Odontoblasts(build bone); Fibroblasts(build fibers);Cementoblasts(build cementum) VERY STRAIGHT FORWARD!!
What are the Epithelial Rests of Malassez “MAL-ES-ES”(ERM)? What cells are they derived from? What will they form?
They originate from HERS (HertwigsEpithelialRootSheath). They go on to help form PDLs
