Composite Depth of Cure — MFDS Part 1 MCQ

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ModerateDental MaterialsComposite Depth of CureMFDS Part 1

For a conventional light-activated resin composite, which combination of factors would be expected to produce the greatest reduction in depth of cure?

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Correct answer: D — Greater material opacity, lower light irradiance and shorter exposure time

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

Option A is correct. Greater opacity increases attenuation and scattering of curing light within the composite, while lower irradiance and a shorter exposure reduce the radiant energy delivered. Together, these factors produce the greatest reduction in polymerisation at depth. Options B–D contain at least one factor that improves curing: increased irradiance, longer exposure or greater translucency. Option E combines three factors favouring greater depth of cure. Darker shades may cure less deeply, but opacity and material formulation are more directly relevant than shade designation alone. Conventional composites should therefore be placed and light-cured according to the manufacturer's specified increment thickness and exposure protocol; a universal 2 mm rule should not be applied uncritically to materials specifically designed and validated for bulk placement.

Reference: Maquère A, DeWolf D, Labrie D, Price RB. Depth of Cure of a Simplified Bulk-Fill Universal Composite and a Conventional Resin-Based Composite. Materials. 2026;19(12):2657. https://pubmed.ncbi.nlm.nih.gov/42355237/