The Periodontium

Cementum
Periodontal ligament
1. Develops from dental folicle
  1. Foms shortly after root formation
    1. Starts with conective tissue/collagen fringes, extending to cementum
      1. Fibroblasts secrete collagen which remodel fringes
2. Fibers change as tooth errupts, then thicken
  1. Narrows with age
    1. Thin in non functional teeth
      1. Functions: Attachment, proprioreceptor, shock absorber
3. Composed of
  1. Cells; Fibroblasts, epithelial cells (malassez,) Undifferenciated mesenchymal cells, Cementoblasts, Macrophages
    1. Ectracellular; Colagen, elastin (immature only), Ground substance (glycoprotein, glycolipids.)
4. Fibroblasts synthesis/degrade collagen for rapid turnover
  1. Mesenchymal cells are source of new PDL cells
    1. Oesteoblasts/Oesteoclasts line bone
      1. Cementoblasts line cementum.No Cementoclasts unless resorbtion of deciduos
5. Collagen, types 1,3+7. Remodelled withe stress forces
  1. 5 principle types; Aveola crest, Horizontal, oblique, apical, inerridicular
    1. They run from cementum-bone. Sharpeys fibres
      1. Ground substance 70% water
6. Rich blood supply; main from superiour and inferiour alveolar arteries,More posteria and mandible, less ants and maxilla
  1. 4 types of nerve endings, mostly free, Nocirecptors+ mechanicreceptor
Alveolar Bone
1. Consists of spongsiosa, sandwiched between buccal and ligual cortical plates
  1. Bone lining known as Bundle bone as attaches PDL bundles
    1. Perforated by forimina for nerves, vessels, known as cribiform plate or Lamina Dura on x-ray (white lining)
Gingivae
1. Gingivae fibres, insert into lamina propria
  1. Groups include; Dentogingival, Alveologingival, circular, dentoperioestial,transseptal
2. Dentogingival Junction
  1. Gingival tissue to tooth
    1. Epithelial and connective parts
      1. Epithelial part
        Statified, squamous epithelial cells
        Junctional epithelial, attached to tooth surface, forms collar, non keratinised
        Sulclar epithelial, lines sulcus, non-keratinised
        Oral gingival is keratinised.
        Junctional epithelial, Flattened cells, line tooth
        attached by hemidesmosomes and have high rate of turmover
        JE has pourous intercellular, can let through antigens, lined with immune cells.
        Connective part
        Different from other connective tissue orally, as contains immflamatory cells.
        Monocytes continually migrate from vessels, through intercellular tissue, out to the sulcus
        Col (interdental papilla,) identical to juntional epithelium
      2. Decreases with age, due to constant low grade imflamatory- Gingival recession
Hyaline Layer

Nächster

The Periodontium

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	Erstellt von Caroline Oxford vor fast 11 Jahre