Oral Anatomy: Gingiva and Periodontium
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Questions and Answers

What separates the gingival epithelium from the underlying connective tissue?

  • Basement membrane (correct)
  • Lamina lucida
  • Lamina densa
  • Rete pegs

    • What is the main component of lamina lucida?

  • Type IV collagen
  • Mucopolysaccharides
  • Keratin
  • Glycoprotein laminin (correct)

    • What is the thickness of the oral epithelium?

  • 0.2-0.3 mm (correct)
  • 0.1-0.2 mm
  • 0.3-0.4 mm
  • 0.4-0.5 mm

    • What is the characteristic of sulcular epithelium?

    <p>Thin without rete pegs and non-keratinized</p> Signup and view all the answers

    What is the function of the junctional epithelium?

    <p>To connect the gingiva to the tooth</p> Signup and view all the answers

    What is the characteristic of junctional epithelium?

    <p>Thick, non-keratinized, and few layers</p> Signup and view all the answers

    What is the function of the basement membrane?

    <p>To separate the epithelium from the connective tissue</p> Signup and view all the answers

    What is the characteristic of oral epithelium?

    <p>Thick, keratinized, and has rete pegs</p> Signup and view all the answers

    What is the main function of keratinocytes in the oral epithelium?

    <p>To provide a physical barrier to infection</p> Signup and view all the answers

    What is the process by which keratinocytes undergo transformation?

    <p>Keratinization</p> Signup and view all the answers

    What type of cells are Langerhans cells?

    <p>Dendritic cells</p> Signup and view all the answers

    Where are melanocytes located in the oral epithelium?

    <p>Basal and spinous layers</p> Signup and view all the answers

    What is the function of Merkel cells?

    <p>To act as tactile receptors</p> Signup and view all the answers

    What is the main difference between orthokeratinization and parakeratinization?

    <p>Orthokeratinization involves the synthesis of keratohyaline granules, while parakeratinization does not</p> Signup and view all the answers

    What is the role of the epithelial cells in innate host defense?

    <p>To respond to bacteria in an interactive signaling</p> Signup and view all the answers

    What is the approximate turnover time for the gingival epithelium?

    <p>10 to 12 days</p> Signup and view all the answers

    What is the gingiva?

    <p>A part of the oral mucosa that covers the alveolar processes of the jaws and surrounds the teeth</p> Signup and view all the answers

    What is the width of the gingiva?

    <p>Varies from 1-9 mm in total</p> Signup and view all the answers

    What is the gingival sulcus?

    <p>The space between the marginal gingiva and the external tooth surface</p> Signup and view all the answers

    What is the ideal depth of the gingival sulcus?

    <p>0 mm</p> Signup and view all the answers

    What is the attached gingiva?

    <p>The part of the gingiva that extends from the free gingival groove to the mucogingival junction</p> Signup and view all the answers

    What determines the shape of the interdental gingiva?

    <p>Both I and II</p> Signup and view all the answers

    What is the histological composition of the gingiva?

    <p>Overlying Stratified Squamous Epithelium and a core of connective tissue</p> Signup and view all the answers

    What is the depth of a clinically normal gingival sulcus?

    <p>2-3 mm</p> Signup and view all the answers

    What is the normal color of the gingiva in adults?

    <p>Coral pink</p> Signup and view all the answers

    What is the shape of the gingiva in relation to the tooth?

    <p>Knife edge</p> Signup and view all the answers

    What is the consistency of normal gingiva?

    <p>Firm and resilient</p> Signup and view all the answers

    What is the surface texture of normal gingiva?

    <p>Stippled</p> Signup and view all the answers

    At what age is stippling of gingiva usually seen?

    <p>By age 6 years</p> Signup and view all the answers

    What is the shape of the gingiva in the interdental area?

    <p>Saddle shaped</p> Signup and view all the answers

    What is one way epithelial cells may respond to bacteria?

    <p>Alteration of cell-signaling events</p> Signup and view all the answers

    What percentage of connective tissue is composed of collagen fibers?

    <p>60%</p> Signup and view all the answers

    What is the main function of the dentogingival group of gingival fibers?

    <p>To extend from the cementum to the periosteum of the facial and lingual bone</p> Signup and view all the answers

    What is the main component of the ground substance in connective tissue?

    <p>Proteoglycans</p> Signup and view all the answers

    What type of fibers provide tensile strength to the lamina propria?

    <p>Collagen fibers type I</p> Signup and view all the answers

    What is the function of the circular group of gingival fibers?

    <p>To course through the connective tissue in a ring-like fashion</p> Signup and view all the answers

    What is one source of blood supply to the gingiva?

    <p>Supraperiosteal arterioles</p> Signup and view all the answers

    What type of cells are the main cells of the connective tissue?

    <p>Fibroblasts</p> Signup and view all the answers

    Study Notes

    The Gingiva

    • The gingiva is part of the oral mucosa, covering the alveolar processes of the jaws and surrounding the teeth, but not adherent to them.
    • It extends to the mucogingival junction, with a varying width of 1-9 mm.
    • The gingiva is divided anatomically into:
      • Marginal gingiva
      • Attached gingiva
      • Interdental areas

    Marginal Gingiva

    • The free gingiva is a knife-edge part of the gingiva, located coronal or above the CEJ, surrounding the tooth in a turtleneck or collar-like manner.
    • It forms the soft tissue wall of the gingival sulcus.
    • The gingival sulcus is a shallow crevice or space around the tooth neck, bounded by the tooth surface and epithelium lining the free margin.
    • The depth of the gingival sulcus is an important clinical parameter, ideally being 0 mm, but clinically normal sulcus is 2-3 mm.

    Attached Gingiva

    • It is firm, resilient, and extends from the free gingival groove to the mucogingival junction.
    • The width of the attached gingiva is an important clinical parameter, differing in various areas of the mouth.
    • The width is greatest in the incisor area (3.5-4.5 mm) and narrower in the posterior area (1.8-1.9 mm).
    • The width increases with age and in supraerupted teeth.

    Interdental Gingiva

    • It is the part of the gingiva filling in the embrasure beneath the contact point.
    • It is either pyramidal or can have a col shape, determined by tooth contact and the width of neighboring teeth.
    • It is completely missing in case of diastema.

    Microscopic Features

    • The gingiva is composed of:
      • Overlying stratified squamous epithelium (SSE)
      • Core of connective tissue (lamina propria)
      • A dividing line between the two, called the basement membrane
    • The epithelium is joined to the underlying connective tissue by the basal lamina, which consists of lamina lucida and lamina densa.
    • The basal lamina acts as a barrier to particulate matter, with a width of 300-400 A°.

    Gingival Epithelium

    • It consists of a continuous lining of SSE, with three different areas:
      1. The oral epithelium, extending from the gingival margin to the mucogingival junction.
      2. The sulcular epithelium, facing the tooth.
      3. The junctional epithelium, apical to the sulcular epithelium, where the gingiva is joined to the tooth.
    • The principal cell type of the gingival epithelium is the keratinocyte, with other cells including Langerhans cells, Merkel cells, and melanocytes.

    Gingival Epithelium Subtypes

    • Oral epithelium: 0.2-0.3 mm in thickness, orthokeratinized or parakeratinized, with rete pegs.
    • Sulcular epithelium: thin, non-keratinized, lacking granulosum and corneum strata, and normally having no Merkel cells.
    • Junctional epithelium: 3-4 layers thick, composed of 2 strata, with a length ranging from 0.25-1.35 mm, and expressing K19.

    Connective Tissue

    • Mainly formed by collagen fibers (60%), fibroblasts, vessels, nerves, and matrix (35%).
    • Consists of two layers:
      1. Papillary layer
      2. Reticular layer
    • Has a cellular and extracellular compartment, with fibroblasts, mast cells, plasma cells, lymphocytes, and neutrophils, and a ground substance composed of proteoglycans, glycoprotein, and fibers.

    Gingival Fibers

    • Arranged in groups, including:
      1. Dentogingival group: originating from the cementum, extending in fan-like conformation toward the crest and outer marginal gingiva.
      2. Circular group: coursing through the connective tissue of marginal and interdental in a ring-like fashion.
      3. Transseptal group: located interproximally, forming horizontal bundles extending between the cementum of approximating teeth.
    • Functions include:
      1. Bracing the marginal gingiva firmly against the tooth.
      2. Providing the rigidity necessary to withstand the forces of mastication.
      3. Uniting the free marginal gingiva with the cementum of the root and the adjacent attached gingiva.

    Blood and Nerve Supply

    • Blood supply is provided through three sources:
      1. Supraperiosteal arterioles
      2. Vessels of the periodontal ligament
      3. Arterioles that emerge from the crest of the interdental septa
    • Nerve supply is provided by the fifth cranial nerve.

    Clinical Features of Normal Gingiva

    • Color: coral pink or salmon red, depending on the degree of vascularity, thickness of keratinization, and presence of pigmented cells.
    • Shape: having a knife-edge with the tooth.
    • Contour: normally following the contour of the tooth, but usually scalloped.
    • Consistency: firm and resilient.
    • Surface texture: orange-peel (stippled) appearance.
    • Position: the position of the gingiva refers to the level at which the gingival margin is attached to the tooth.

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    The Gingiva - PDF

    Description

    This quiz covers the structure and function of the gingiva and periodontium, including the marginal gingiva, attached gingiva, and interdental areas.

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