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Restorative & Materials · single question

Why may a thin layer of flowable composite be placed at the gingival floor of a Class II preparation?

  1. It eliminates the need for a separate liner or base
  2. It allows fewer total increments of composite
  3. Its low viscosity improves adaptation and reduces marginal voids
  4. It is significantly stronger than packable composite
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Correct answer: C. Its low viscosity improves adaptation and reduces marginal voids

  • A. A flowable is not a substitute for pulpal protection where a liner is genuinely indicated.
  • B. Reducing increments is not the rationale; incremental placement is still required to control shrinkage stress.
  • C. Correct. Flowable composite has LOW VISCOSITY and therefore flows into the internal line angles and adapts intimately to the gingival floor — the region most prone to VOIDS and marginal gaps because of restricted access and the polymerisation stress of packable material. The result is a better marginal seal and fewer voids at the most caries-susceptible margin. Its lower elastic modulus may also absorb some polymerisation stress.
  • D. Flowable composite is WEAKER than packable composite because of lower filler loading — it is used as a thin adaptive layer, never as the bulk restorative in a stress-bearing area.

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