Restorative & Materials · single question
What is the 'Ferrule effect' in restorative dentistry?
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Correct answer: C. A design feature in which a crown encircles and engages coronal tooth structure above the finish line, providing resistance and retention to a tooth with a post and core
The Ferrule effect refers to a crown preparation design in which a band of crown structure (2 mm of parallel dentin walls) above the finish line (or above the composite core) encircles the tooth. This creates a 'ferrule' — similar to the metal band around the base of a walking cane — that provides superior fracture resistance and retention to endodontically treated teeth restored with posts and cores. A minimum ferrule height of 2 mm of sound dentin is recommended. The ferrule effect significantly reduces the incidence of root fractures and crown failures. Teeth without an adequate ferrule show a dramatically increased failure rate.
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