Composite Restoration — ORE Part 1 MCQ

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ModerateDental MaterialsComposite RestorationORE Part 1

A patient requires a large MOD restoration using a conventional light-cured posterior composite; the material is not a bulk-fill composite. Which placement technique is most appropriate to reduce polymerisation-shrinkage stress?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — Place oblique increments no thicker than 2 mm

Explanation lettering: D = shown as A · E = shown as B · A = shown as D · B = shown as E

A is correct. With a conventional light-cured posterior composite, placing small oblique increments (approximately 2 mm or less) limits the bonded surface configuration and volume polymerising at each cure, reducing polymerisation-shrinkage stress and associated cuspal deflection. In an MOD cavity model, incremental placement produced less cuspal deflection than bulk placement. Bulk filling is a reasonable technique only when using a bulk-fill material within its specified curing depth; it is not appropriate for the conventional composite stated here. Four-millimetre horizontal layers exceed the usual increment depth for conventional composite and increase the polymerising volume. Flowable composite alone is generally unsuitable as the full bulk restorative material in a large posterior cavity. Self-cure placement in one large increment does not remove polymerisation shrinkage stress.

Reference: Park J, Chang J, Ferracane J, Lee IB. How should composite be layered to reduce shrinkage stress: incremental or bulk filling? Dental Materials. 2008. https://pubmed.ncbi.nlm.nih.gov/18433857/