Composite Depth of Cure — NDEB AFK MCQ

Correct answer: D — 2.0-2.5 mm

The standard depth of cure for most light-cured composite resins is approximately 2.0-2.5 mm per increment when cured with adequate light intensity (>400 mW/cm²) for the recommended time (typically 20 seconds for most LED lights). This is why incremental layering technique (placing composite in 2 mm layers) is recommended for deep restorations — each layer must be within the effective curing depth. Bulk-fill composites are specifically formulated to cure at 4-5 mm depth in a single increment due to increased translucency and modified photo-initiators.

Reference: Anusavice – Phillips' Science of Dental Materials, 13th ed., 2022