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51 Cards in this Set

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What are Short Term Incremental Lines?
Cross striations in enamel due to the dinural cycle of amealoblasts. They are 4um in length.
What are the Striae of Retzius?
These represent disturbences in enamel production. Prominent Striae is the neo-natal line.
What are Perikymata?
Surface manifestaions of the Striae of Retzius.
What are Hunter-Schreger bands?
Bands caused by the change in direction of groups of enamel rods.
What is gnarled enamel?
When groups of enamel rods spiral around each other (eg under cusps)
What is Primless enamel?
Enamel when it is first or last laid down. Primless because there are no tomes processes. These areas are lighter because they have less organic matter.
What feature strengthens the DEJ so there is stronger cohesion?
Scalloping
What are Enamel Tufts and where are they best seen?
Tufts are hypocalcified enamel rods that go from the DEJ to the enamel. Best seen in transverse sections.
What are Enamel Lamellae and where are they best seen?
Lamellae are similar to geographical faults and are hypomineralised. Best seen in transverse sections.
What are Enamel Spindles and where are they best seen?
Spindles are remnants of odontoblast tubules. Mostly seen beneath cusps in longitudinal sections.
What constitutes enamel?
By weight:
Hydroxyapatite - 96%
Water - 2%
Organic - 2%
What constitues dentine?
By weight:
Inorganic - 70% (smaller hydroxyapatite than enamel)
Water - 10%
Organic - 20% (mostly type I collagen, also glycosaminoglycans)
What is Predentine?
Unmineralised dentine (newly laid)
In what shape is predentine mineralised and how long does it take?
It can either have a linear mineralisation front (when it occurs slowly) or occur in a globular form. It takes around 1 day.
Which is more mineralised? Peritubular or Intertubular Dentine?
Peritubular
What kind of dentine suround odontoblast tubules? What is it's composition?
Peritubular dentine - highly mineralised.
What kind of dentine is between dentine tubules? What is it's composition?
Intertubular dentine - high levels of collagen fibres enveloped in amorphous protein.
What is newly formed dentine called?
Mantle dentine
What is the name of dentine laid down before root formation is complete?
Primary dentine
What is the name of dentine laid down after root formation is complete?
Secondary dentine - decreases of pulp chamber with age
What happens to dentine tubules as they run from Primary to Secondary dentine? Why?
They bend sharply due to odontoblast crowding.
Tertiary dentine?
Reparative
What is Sclerotic dentine?
Mineralised dentine tubules which are transparent.
What is interglobular dentine?
Hypomineralised dentine caused by globular dentine not fusing completley.
What are the lines of Von Ebner?
Short term incremental lines in dentine
What are Contour line of Owen?
Lines showing disturbance in dentine production.
Where and what is the Granular Layer of Tomes?
The Granular Layer of Tomes is located in dentine under cementum and may possibly be due to dentine tubules crossing back/looping.
What cells are contained in dental pulp?
Odontoblasts, reserve cells, fibroblasts, macrophages & odontoclasts
What vessels are contained in the dental pulp?
Aerterioles, capillaries, venules, Arterio-venous anastomes.
What are vessels of the dental pulp inervated by?
Vasomotor fibres of the autonomic ganglia
Which nerve fibres of the dental pulp are myelinated? Vasomotor or pain fibres?
Pain fibres
When is the myelinated sheath lost?
Subodontoblastic zone - Cell Free Zone of Weil
Where is the Cell Free Zone of Weil?
Under the odontoblasts
What is the name of the nerve plexus in the subodontoblastic zone?
Plexus of Raschkow or Parietal Plexus
What are the 3 types of nerves that innervate dentine?
Recurrent - go from POR to predentine and back
Predentine - go from POR to predentine
Intratubular - go from POR to dentinal tubules
What cells of the developing tooth bud become cementoblasts?
Cells of the Dental Follicle.
Which cells of the developing tooth bud become amealoblasts?
Inner Enamel Epithelial cells of the Enamel Organ
Which cells of the developing tooth bud become Odontoblasts?
Cells of the Dental Papilla.
Where is acellular cementum located? What does it supply attachments for?
In the cervical region. It supplies attachments for the PDL
Where is cellular cementum found? What does it contain?
Cellular cementum is found apically. It contains cementocytes in lacunae.
Cementocyte lacunae canniculi are directed towards what?
The PDL which has a blood supply
What are Sharpey's/Extrinsic/Principle fibres made by? What are they made from and are they mineralised?
Fibroblasts. Made from collagen, and they are mineralised.
Name the 5 groups of Sharpey's/Extrinsic/Principle fibres, from cervix to apex.
Alveolar Crest
Horizontal
Oblique
Appical
Interradicular
Name the 5 main groups of the Gingival Ligament.
Dentogingival
Alveologingival
Circular
Dentoperiosteal
Interdental
What is bundle bone/lamina dura/cribriform plate? What are some features?
Alveolar bone + Sharpey's fibres. Lots of forima and no trabeculae.
What is the name of the areas between Sharpey's Fibres?
Interstitial space
What are the elastic fibres in the PDL called and what is their development state?
Oxytalan fibres - immature
By what mechanism does the cartilage of the condyles develope?
Intramembranous Ossification
Does the condyle cartilage of the TMJ have a perichondrium?
Yes
How many minisci are in the TMJ?
One - complete
What are the 3 theories of Dentine sensitivity?
1. Dentine is innervated directly
2. Odontoblasts act as receptors and have gap junctions between each other and nerve fibres for communication
3. Hydrodynmaic theory: Receptors in pulp are stimulated via fluid movement through the tubules- this explains why local anaesthetics don't work