Composite Resins
Composition
Resin matrix (Bis-GMA, UDMA, TEGDMA), filler particles (silica/glass), and a silane coupling agent linking them.
Filler-based Classification
- Microfilled — best polish/esthetics, lower strength.
- Hybrid / microhybrid — best overall balance of strength and polish.
- Nanofill / nanohybrid — latest; good esthetics and strength.
Key Concepts
- Depth of cure — place in increments of ≤ 2 mm to ensure complete polymerization.
- Polymerization shrinkage — causes stress at margins; minimised by incremental placement.
- C-factor — ratio of bonded to unbonded surfaces; a higher C-factor means more shrinkage stress.
Exam Tips ⭐
Hybrid = best overall; microfill = best polish; cure in ≤2 mm increments; high C-factor = more stress.