Restorative & Materials · single question
The incisal margin design for a porcelain veneer preparation is BEST described as:
Show answer and explanation
Correct answer: A. Chamfer
The chamfer is the preferred incisal finish line for veneer preparations. It provides a slight concavity that gives adequate bulk of porcelain at the margin for strength without being overly aggressive on tooth structure. Shoulder margins are used for full-coverage crowns. A feather edge provides insufficient support. A butt joint (window preparation) is used when an incisal edge reduction approach is chosen in some cases.
- A. ✅ CORRECT – A chamfer provides adequate porcelain bulk and smooth transition at the incisal edge of veneer preparations.
- B. ❌ A shoulder finish line provides a 90° margin — used for all-ceramic crowns, not typically for veneers.
- C. ❌ A feather edge (knife edge) provides too little support and leads to porcelain fracture.
- D. ❌ A butt joint is used in the 'window' veneer preparation variant where the incisal edge is preserved — but the question asks about standard incisal margin design.
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