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Bases, Liners, and Matrices Flashcards

7 cards from real EFDA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Bases, Liners, and Matrices flashcards as text

  1. Why is zinc oxide eugenol (ZOE) cement considered a 'sedative' base?

    Answer: Eugenol has a palliative effect that reduces pulpal inflammation and sensitivity

    Eugenol's analgesic and obtundent properties soothe irritated pulp tissue, making ZOE ideal for symptomatic or recently excavated teeth.

  2. When using a sectional matrix system, the ring retainer is placed:

    Answer: Into the embrasures to separate teeth and stabilize the band

    The separation ring is inserted into the buccal and lingual embrasures to press the matrix band tight against the proximal box.

  3. A liner differs from a base primarily in that a liner:

    Answer: Is a thin layer applied mainly for biological protection rather than mechanical support

    Liners are applied in thin layers (under 0.5 mm) to provide biological and chemical protection without the bulk or compressive strength of a base.

  4. What happens if the matrix band is not burnished (adapted) to the gingival margin before placing amalgam?

    Answer: A ledge or flash of amalgam will form at the gingival margin

    An unadapted band leaves a gap at the gingival margin where amalgam can flow, creating a ledge that predisposes to plaque accumulation.

  5. Which liner is appropriate for use directly under composite resin without inhibiting polymerization?

    Answer: Light-cured calcium hydroxide or resin-modified glass ionomer

    Light-cured calcium hydroxide and resin-modified glass ionomer liners are compatible with composite resin and will not inhibit its polymerization.

  6. The primary function of a base in a deep cavity preparation is to:

    Answer: Provide thermal and mechanical protection for the pulp while building up the preparation floor

    Bases replace missing dentin bulk to protect the pulp from thermal shock and resist compressive forces from condensation.

  7. When adapting a matrix band to a tooth with an unusual or pronounced cervical contour, which action helps ensure a proper gingival seal?

    Answer: Burnishing the band apically against the tooth surface with a ball burnisher

    Burnishing the band apically with a ball burnisher adapts it closely to the cervical contour to eliminate gaps at the gingival margin.